1
|
Bevilacqua M, Feroldi S, Windel F, Menoud P, Salamanca-Giron RF, Zandvliet SB, Fleury L, Hummel FC, Raffin E. Single session cross-frequency bifocal tACS modulates visual motion network activity in young healthy population and stroke patients. Brain Stimul 2024; 17:660-667. [PMID: 38763414 DOI: 10.1016/j.brs.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/07/2024] [Accepted: 05/15/2024] [Indexed: 05/21/2024] Open
Abstract
BACKGROUND Phase synchronization over long distances underlies inter-areal communication and importantly, modulates the flow of information processing to adjust to cognitive demands. OBJECTIVE This study investigates the impact of single-session, cross-frequency (Alpha-Gamma) bifocal transcranial alternating current stimulation (cf-tACS) to the cortical visual motion network on inter-areal coupling between the primary visual cortex (V1) and the medio-temporal area (MT) and on motion direction discrimination. METHODS Based on the well-established phase-amplitude coupling (PAC) mechanism driving information processing in the visual system, we designed a novel directionally tuned cf-tACS protocol. Directionality of information flow was inferred from the area receiving low-frequency tACS (e.g., V1) projecting onto the area receiving high-frequency tACS (e.g., MT), in this case, promoting bottom-up information flow (Forward-tACS). The control condition promoted the opposite top-down connection (from MT to V1, called Backward-tACS), both compared to a Sham-tACS condition. Task performance and EEG activity were recorded from 45 young healthy subjects. An additional cohort of 16 stroke patients with occipital lesions and impairing visual processing was measured to assess the influence of a V1 lesion on the modulation of V1-MT coupling. RESULTS The results indicate that Forward cf-tACS successfully modulated bottom-up PAC (V1 α-phase-MT ɣ-amplitude) in both cohorts, while producing opposite effects on the reverse MT-to-V1 connection. Backward-tACS did not change V1-MT PAC in either direction in healthy participants but induced a slight decrease in bottom-up PAC in stroke patients. However, these changes in inter-areal coupling did not translate into cf-tACS-specific behavioural improvements. CONCLUSIONS Single session cf-tACS can alter inter-areal coupling in intact and lesioned brains but is probably not enough to induce longer-lasting behavioural effects in these cohorts. This might suggest that a longer daily visual training protocol paired with tACS is needed to unveil the relationship between externally applied oscillatory activity and behaviourally relevant brain processing.
Collapse
Affiliation(s)
- Michele Bevilacqua
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland.
| | - Sarah Feroldi
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Fabienne Windel
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland
| | - Pauline Menoud
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland
| | - Roberto F Salamanca-Giron
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland
| | - Sarah B Zandvliet
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland
| | - Lisa Fleury
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland
| | - Friedhelm C Hummel
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland; Department of Clinical Neuroscience, University of Geneva Medical School, Geneva, Switzerland
| | - Estelle Raffin
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Neuro-X Institute, Clinique Romande de Réadaptation, (EPFL Valais), Sion, Switzerland.
| |
Collapse
|
2
|
Zhu JP, Zhang JY. Feature variability determines specificity and transfer in multiorientation feature detection learning. J Vis 2024; 24:2. [PMID: 38691087 PMCID: PMC11079675 DOI: 10.1167/jov.24.5.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 02/26/2024] [Indexed: 05/03/2024] Open
Abstract
Historically, in many perceptual learning experiments, only a single stimulus is practiced, and learning is often specific to the trained feature. Our prior work has demonstrated that multi-stimulus learning (e.g., training-plus-exposure procedure) has the potential to achieve generalization. Here, we investigated two important characteristics of multi-stimulus learning, namely, roving and feature variability, and their impacts on multi-stimulus learning and generalization. We adopted a feature detection task in which an oddly oriented target bar differed by 16° from the background bars. The stimulus onset asynchrony threshold between the target and the mask was measured with a staircase procedure. Observers were trained with four target orientation search stimuli, either with a 5° deviation (30°-35°-40°-45°) or with a 45° deviation (30°-75°-120°-165°), and the four reference stimuli were presented in a roving manner. The transfer of learning to the swapped target-background orientations was evaluated after training. We found that multi-stimulus training with a 5° deviation resulted in significant learning improvement, but learning failed to transfer to the swapped target-background orientations. In contrast, training with a 45° deviation slowed learning but produced a significant generalization to swapped orientations. Furthermore, a modified training-plus-exposure procedure, in which observers were trained with four orientation search stimuli with a 5° deviation and simultaneously passively exposed to orientations with high feature variability (45° deviation), led to significant orientation learning generalization. Learning transfer also occurred when the four orientation search stimuli with a 5° deviation were presented in separate blocks. These results help us to specify the condition under which multistimuli learning produces generalization, which holds potential for real-world applications of perceptual learning, such as vision rehabilitation and expert training.
Collapse
Affiliation(s)
- Jun-Ping Zhu
- School of Psychological and Cognitive Sciences, and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Jun-Yun Zhang
- School of Psychological and Cognitive Sciences, and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| |
Collapse
|
3
|
Fahrenthold BK, Cavanaugh MR, Tamhankar M, Lam BL, Feldon SE, Johnson BA, Huxlin KR. Training in Cortically Blinded Fields Appears to Confer Patient-Specific Benefit Against Retinal Thinning. Invest Ophthalmol Vis Sci 2024; 65:29. [PMID: 38635245 PMCID: PMC11033601 DOI: 10.1167/iovs.65.4.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 03/06/2024] [Indexed: 04/19/2024] Open
Abstract
Purpose Damage to the adult primary visual cortex (V1) causes vision loss in the contralateral hemifield, initiating a process of transsynaptic retrograde degeneration (TRD). Here, we examined retinal correlates of TRD using a new metric to account for global changes in inner retinal thickness and asked if perceptual training in the intact or blind field impacts its progression. Methods We performed a meta-analysis of optical coherence tomography data in 48 participants with unilateral V1 stroke and homonymous visual defects who completed clinical trial NCT03350919. After measuring the thickness of the macular ganglion cell and inner plexiform layer (GCL-IPL) and the peripapillary retinal nerve fiber layer (RNFL), we computed individual laterality indices (LI) at baseline and after ∼6 months of daily motion discrimination training in the intact or blind field. Increasingly positive LI denoted greater layer thinning in retinal regions affected versus unaffected by the cortical damage. Results Pretraining, the affected GCL-IPL and RNFL were thinner than their unaffected counterparts, generating LI values positively correlated with time since stroke. Participants trained in their intact field exhibited increased LIGCL-IPL. Those trained in their blind field had no significant change in LIGCL-IPL. LIRNFL did not change in either group. Conclusions Relative shrinkage of the affected versus unaffected macular GCL-IPL can be reliably measured at an individual level and increases with time post-V1 stroke. Relative thinning progressed during intact-field training but appeared to be halted by training within the blind field, suggesting a potentially neuroprotective effect of this simple behavioral intervention.
Collapse
Affiliation(s)
- Berkeley K. Fahrenthold
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Matthew R. Cavanaugh
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Madhura Tamhankar
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States
| | - Steven E. Feldon
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Brent A. Johnson
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, New York, United States
| | - Krystel R. Huxlin
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| |
Collapse
|
4
|
Yang (杨菁艺) J, Saionz EL, Cavanaugh MR, Fahrenthold BK, Melnick MD, Tadin D, Briggs F, Carrasco M, Huxlin KR. Limited restoration of contrast sensitivity with training after V1 damage in humans. eNeuro 2024; 11:ENEURO.0020-24.2024. [PMID: 38395611 PMCID: PMC10941636 DOI: 10.1523/eneuro.0020-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
Stroke damage to the primary visual cortex (V1) causes severe visual deficits, which benefit from perceptual retraining. However, whereas training with high-contrast stimuli can locally restore orientation and motion direction discrimination abilities at trained locations, it only partially restores luminance contrast sensitivity (CS). Recent work revealed that high-contrast discrimination abilities may be preserved in the blind field of some patients early after stroke. Here, we asked if CS for orientation and direction discrimination is similarly preserved inside the blind field, to what extent, and whether it could benefit from a visual training intervention. Thirteen subacute patients (<3 months post-V1-stroke) and 12 chronic patients (>6 months post-V1-stroke) were pre-tested, then trained to discriminate either orientation or motion direction of Gabor patches of progressively lower contrasts as their performance improved. At baseline, more subacute than chronic participants could correctly discriminate the orientation of high-contrast Gabors in their blind field, but all failed to perform this task at lower contrasts, even when 10Hz flicker or motion direction were added. Training improved CS in a greater portion of subacute than chronic participants, but no-one attained normal CS, even when stimuli contained flicker or motion. We conclude that, unlike the near-complete training-induced restoration of high-contrast orientation and motion direction discrimination abilities, V1 damage in adulthood may severely limit the residual visual system's ability to regain normal CS. Our results support the notion that CS involves different neural substrates and computations than those required for orientation and direction discrimination in V1-damaged visual systems.Significance statement Stroke-induced V1 damage in adult humans induces a rapid and severe impairment of contrast sensitivity for orientation and motion direction discrimination in the affected hemifield, although discrimination of high-contrast stimuli can persist for several months. Adaptive training with Gabor patches of progressively lower contrasts improves contrast sensitivity for both orientation and motion discriminations in the blind-field of subacute (<3 months post-stroke) and chronic (>6 months post-stroke) participants; however, it fails to restore normal contrast sensitivity. Nonetheless, more subacute than chronic stroke participants benefit from such training, particularly when discriminating the orientation of static, non-flickering targets. Thus, contrast sensitivity appears critically dependent on processing within V1, with perceptual training displaying limited potential to fully restore it after V1 damage.
Collapse
Affiliation(s)
- Jingyi Yang (杨菁艺)
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Elizabeth L. Saionz
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Matthew R. Cavanaugh
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Berkeley K. Fahrenthold
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Michael D. Melnick
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
| | - Duje Tadin
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
| | - Farran Briggs
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
| | - Marisa Carrasco
- Department of Psychology and Center for Neural Science, New York University, New York, New York 10003
| | - Krystel R. Huxlin
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
| |
Collapse
|
5
|
Namgung E, Kim YH, Lee EJ, Sasaki Y, Watanabe T, Kang DW. Functional connectivity interacts with visual perceptual learning for visual field recovery in chronic stroke. Sci Rep 2024; 14:3247. [PMID: 38332042 PMCID: PMC10853510 DOI: 10.1038/s41598-024-52778-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/23/2024] [Indexed: 02/10/2024] Open
Abstract
A reciprocal relationship between perceptual learning and functional brain changes towards perceptual learning effectiveness has been demonstrated previously; however, the underlying neural correlates remain unclear. Further, visual perceptual learning (VPL) is implicated in visual field defect (VFD) recovery following chronic stroke. We investigated resting-state functional connectivity (RSFC) in the visual cortices associated with mean total deviation (MTD) scores for VPL-induced VFD recovery in chronic stroke. Patients with VFD due to chronic ischemic stroke in the visual cortex received 24 VPL training sessions over 2 months, which is a dual discrimination task of orientation and letters. At baseline and two months later, the RSFC in the ipsilesional, interhemispheric, and contralesional visual cortices and MTD scores in the affected hemi-field were assessed. Interhemispheric visual RSFC at baseline showed the strongest correlation with MTD scores post-2-month VPL training. Notably, only the subgroup with high baseline interhemispheric visual RSFC showed significant VFD improvement following the VPL training. The interactions between the interhemispheric visual RSFC at baseline and VPL led to improvement in MTD scores and largely influenced the degree of VFD recovery. The interhemispheric visual RSFC at baseline could be a promising brain biomarker for the effectiveness of VPL-induced VFD recovery.
Collapse
Affiliation(s)
- Eun Namgung
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
| | | | - Eun-Jae Lee
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Yuka Sasaki
- Department of Cognitive, Linguistic and Psychological Sciences, Brown University, Providence, USA
| | - Takeo Watanabe
- Department of Cognitive, Linguistic and Psychological Sciences, Brown University, Providence, USA
| | - Dong-Wha Kang
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
| |
Collapse
|
6
|
Fahrenthold BK, Cavanaugh MR, Tamhankar M, Lam BL, Feldon SE, Johnson BA, Huxlin KR. Training in cortically-blind fields confers patient-specific benefit against retinal thinning after occipital stroke. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.12.19.23298260. [PMID: 38196617 PMCID: PMC10775322 DOI: 10.1101/2023.12.19.23298260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Purpose Damage to the adult primary visual cortex (V1) causes vision loss in the contralateral hemifield, initiating a process of trans-synaptic retrograde degeneration (TRD). Here, we examined retinal correlates of TRD using a new metric to account for global changes in inner retinal thickness, and asked if perceptual training in the intact or blind field impacts its progression. Methods We performed a meta-analysis of optical coherence tomography (OCT) data in 48 participants with unilateral V1 stroke and homonymous visual defects, who completed clinical trial NCT03350919. After measuring the thickness of the macular ganglion cell and inner plexiform layers (GCL-IPL), and the peripapillary retinal nerve fiber layer (RNFL), we computed individual laterality indices (LI) at baseline and after ~6 months of daily motion discrimination training in the intact- or blind-field. Increasingly positive LI denoted greater layer thinning in retinal regions affected versus unaffected by the cortical damage. Results Pre-training, the affected GCL-IPL and RNFL were thinner than their unaffected counterparts, generating LI values positively correlated with time since stroke. Participants trained in their intact-field exhibited increased LIGCL-IPL. Those trained in their blind-field had no significant change in LIGCL-IPL. LIRNFL did not change in either group. Conclusions Relative shrinkage of the affected versus unaffected macular GCL-IPL can be reliably measured at an individual level and increases with time post-V1 stroke. Relative thinning progressed during intact-field training, but appeared to be halted by training within the blind field, suggesting a potentially neuroprotective effect of this simple behavioral intervention.
Collapse
Affiliation(s)
- Berkeley K. Fahrenthold
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Matthew R. Cavanaugh
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Madhura Tamhankar
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Steven E. Feldon
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Brent A. Johnson
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY, USA
| | - Krystel R. Huxlin
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| |
Collapse
|
7
|
Grzeczkowski L, Shi Z, Rolfs M, Deubel H. Perceptual learning across saccades: Feature but not location specific. Proc Natl Acad Sci U S A 2023; 120:e2303763120. [PMID: 37844238 PMCID: PMC10614914 DOI: 10.1073/pnas.2303763120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 09/13/2023] [Indexed: 10/18/2023] Open
Abstract
Perceptual learning is the ability to enhance perception through practice. The hallmark of perceptual learning is its specificity for the trained location and stimulus features, such as orientation. For example, training in discriminating a grating's orientation improves performance only at the trained location but not in other untrained locations. Perceptual learning has mostly been studied using stimuli presented briefly while observers maintained gaze at one location. However, in everyday life, stimuli are actively explored through eye movements, which results in successive projections of the same stimulus at different retinal locations. Here, we studied perceptual learning of orientation discrimination across saccades. Observers were trained to saccade to a peripheral grating and to discriminate its orientation change that occurred during the saccade. The results showed that training led to transsaccadic perceptual learning (TPL) and performance improvements which did not generalize to an untrained orientation. Remarkably, however, for the trained orientation, we found a complete transfer of TPL to the untrained location in the opposite hemifield suggesting high flexibility of reference frame encoding in TPL. Three control experiments in which participants were trained without saccades did not show such transfer, confirming that the location transfer was contingent upon eye movements. Moreover, performance at the trained location, but not at the untrained location, was also improved in an untrained fixation task. Our results suggest that TPL has both, a location-specific component that occurs before the eye movement and a saccade-related component that involves location generalization.
Collapse
Affiliation(s)
- Lukasz Grzeczkowski
- Allgemeine und Experimentelle Psychologie, Department Psychologie, Ludwig-Maximilians-Universität, Munich80802, Germany
- Department Psychologie, Humboldt-Universität zu Berlin, Berlin12489, Germany
| | - Zhuanghua Shi
- Allgemeine und Experimentelle Psychologie, Department Psychologie, Ludwig-Maximilians-Universität, Munich80802, Germany
| | - Martin Rolfs
- Department Psychologie, Humboldt-Universität zu Berlin, Berlin12489, Germany
| | - Heiner Deubel
- Allgemeine und Experimentelle Psychologie, Department Psychologie, Ludwig-Maximilians-Universität, Munich80802, Germany
| |
Collapse
|
8
|
Yang J, Saionz EL, Cavanaugh MR, Fahrenthold BK, Melnick MD, Tadin D, Briggs F, Carrasco M, Huxlin KR. Contrast sensitivity: a fundamental limit to vision restoration after V1 damage. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.08.31.23294827. [PMID: 37693553 PMCID: PMC10491352 DOI: 10.1101/2023.08.31.23294827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Stroke damage to the primary visual cortex (V1) causes severe visual deficits, which benefit from perceptual retraining. However, whereas training with high-contrast stimuli can locally restore orientation and direction discrimination abilities at trained locations, it only partially restores luminance contrast sensitivity (CS). Recent work revealed that high-contrast discrimination abilities may be preserved in the blind field of some patients early after stroke. Here, we asked if CS for orientation and direction discrimination is similarly preserved inside the blind field, to what extent, and whether it could benefit from a visual training intervention. Thirteen subacute (<3 months post-V1-stroke) and 12 chronic (>6 months post-V1-stroke) participants were pre-tested, then trained to discriminate either orientation or motion direction of Gabor patches of progressively lower contrasts. At baseline, more subacute than chronic participants could correctly discriminate the orientation of high-contrast Gabors in their blind field, but all failed to perform this task at lower contrasts, even when 10Hz flicker or motion direction were added. Training improved CS in a greater portion of subacute than chronic participants, but no-one attained normal CS, even when stimuli contained flicker or motion. We conclude that, unlike the near-complete training-induced restoration of high-contrast orientation and direction discrimination, there is limited capacity for restoring CS after V1 damage in adulthood. Our results suggest that CS involves different neural substrates and computations than those required for orientation and direction discrimination in V1-damaged visual systems.
Collapse
Affiliation(s)
- Jingyi Yang
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Elizabeth L. Saionz
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Matthew R. Cavanaugh
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Berkeley K. Fahrenthold
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Michael D. Melnick
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Duje Tadin
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Farran Briggs
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York 14642
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| | - Marisa Carrasco
- Department of Psychology and Center for Neural Science, New York University, NY, NY 10003
| | - Krystel R. Huxlin
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, New York 14642
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York 14642
- Department of Brain & Cognitive Sciences, University of Rochester, Rochester, New York 14627
- Center for Visual Science, University of Rochester, Rochester, New York 14627
| |
Collapse
|
9
|
Bevilacqua M, Huxlin KR, Hummel FC, Raffin E. Pathway and directional specificity of Hebbian plasticity in the cortical visual motion processing network. iScience 2023; 26:107064. [PMID: 37408682 PMCID: PMC10319215 DOI: 10.1016/j.isci.2023.107064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 02/14/2023] [Accepted: 06/02/2023] [Indexed: 07/07/2023] Open
Abstract
Cortico-cortical paired associative stimulation (ccPAS), which repeatedly pairs single-pulse transcranial magnetic stimulation (TMS) over two distant brain regions, is thought to modulate synaptic plasticity. We explored its spatial selectivity (pathway and direction specificity) and its nature (oscillatory signature and perceptual consequences) when applied along the ascending (Forward) and descending (Backward) motion discrimination pathway. We found unspecific connectivity increases in bottom-up inputs in the low gamma band, probably reflecting visual task exposure. A clear distinction in information transfer occurred in the re-entrant alpha signals, which were only modulated by Backward-ccPAS, and predictive of visual improvements in healthy participants. These results suggest a causal involvement of the re-entrant MT-to-V1 low-frequency inputs in motion discrimination and integration in healthy participants. Modulating re-entrant input activity could provide single-subject prediction scenarios for visual recovery. Visual recovery might indeed partly rely on these residual inputs projecting to spared V1 neurons.
Collapse
Affiliation(s)
- Michele Bevilacqua
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, EPFL, Geneva, Switzerland
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Krystel R. Huxlin
- The Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Friedhelm C. Hummel
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, EPFL, Geneva, Switzerland
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
- Clinical Neuroscience, University of Geneva Medical School, Geneva, Switzerland
| | - Estelle Raffin
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, EPFL, Geneva, Switzerland
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| |
Collapse
|
10
|
Leitner MC, Ladek AM, Hutzler F, Reitsamer H, Hawelka S. Placebo effect after visual restitution training: no eye-tracking controlled perimetric improvement after visual border stimulation in late subacute and chronic visual field defects after stroke. Front Neurol 2023; 14:1114718. [PMID: 37456634 PMCID: PMC10339290 DOI: 10.3389/fneur.2023.1114718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 06/13/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction A significant number of Restitution Training (RT) paradigms claim to ameliorate visual field loss after stroke by re-activating neuronal connections in the residual visual cortex due to repeated bright light-stimulation at the border of the blind and intact fields. However, the effectiveness of RT has been considered controversial both in science and clinical practice for years. The main points of the controversy are (1) the reliability of perimetric results which may be affected by compensatory eye movements and (2) heterogeneous samples consisting of patients with visual field defects and/or visuospatial neglect. Methods By means of our newly developed and validated Virtual Reality goggles Salzburg Visual Field Trainer (SVFT) 16 stroke patients performed RT on a regular basis for 5 months. By means of our newly developed and validated Eye Tracking Based Visual Field Analysis (EFA), we conducted a first-time full eye-movement-controlled perimetric pre-post intervention study. Additionally, patients subjectively rated the size of their intact visual field. Results Analysis showed that patients' mean self-assessment of their subjective visual field size indicated statistically significant improvement while, in contrast, objective eye tracking controlled perimetric results revealed no statistically significant effect. Discussion Bright-light detection RT at the blind-field border solely induced a placebo effect and did not lead to training-induced neuroplasticity in the visual cortex of the type needed to ameliorate the visual field size of stroke patients.
Collapse
Affiliation(s)
- Michael Christian Leitner
- Salzburg University of Applied Sciences, Salzburg, Austria
- Centre for Cognitive Neuroscience (CCNS), University of Salzburg, Salzburg, Austria
- Department of Psychology, University of Salzburg, Salzburg, Austria
| | - Anja-Maria Ladek
- Research Program for Experimental Ophthalmology and Glaucoma Research, Department of Ophthalmology and Optometry, University Hospital of the Paracelsus Medical University Salzburg, Salzburg, Austria
- Department of Ophthalmology and Optometry, SALK, University Hospital of the Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Florian Hutzler
- Centre for Cognitive Neuroscience (CCNS), University of Salzburg, Salzburg, Austria
- Department of Psychology, University of Salzburg, Salzburg, Austria
| | - Herbert Reitsamer
- Research Program for Experimental Ophthalmology and Glaucoma Research, Department of Ophthalmology and Optometry, University Hospital of the Paracelsus Medical University Salzburg, Salzburg, Austria
- Department of Ophthalmology and Optometry, SALK, University Hospital of the Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Stefan Hawelka
- Centre for Cognitive Neuroscience (CCNS), University of Salzburg, Salzburg, Austria
- Department of Psychology, University of Salzburg, Salzburg, Austria
| |
Collapse
|
11
|
Wu D, Wang Y, Liu N, Wang P, Sun K, Xiao W. High-definition transcranial direct current stimulation of the left middle temporal complex does not affect visual motion perception learning. Front Neurosci 2022; 16:988590. [PMID: 36117616 PMCID: PMC9474993 DOI: 10.3389/fnins.2022.988590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Visual perceptual learning (VPL) refers to the improvement in visual perceptual abilities through training and has potential implications for clinical populations. However, improvements in perceptual learning often require hundreds or thousands of trials over weeks to months to attain, limiting its practical application. Transcranial direct current stimulation (tDCS) could potentially facilitate perceptual learning, but the results are inconsistent thus far. Thus, this research investigated the effect of tDCS over the left human middle temporal complex (hMT+) on learning to discriminate visual motion direction. Twenty-seven participants were randomly assigned to the anodal, cathodal and sham tDCS groups. Before and after training, the thresholds of motion direction discrimination were assessed in one trained condition and three untrained conditions. Participants were trained over 5 consecutive days while receiving 4 × 1 ring high-definition tDCS (HD-tDCS) over the left hMT+. The results showed that the threshold of motion direction discrimination significantly decreased after training. However, no obvious differences in the indicators of perceptual learning, such as the magnitude of improvement, transfer indexes, and learning curves, were noted among the three groups. The current study did not provide evidence of a beneficial effect of tDCS on VPL. Further research should explore the impact of the learning task characteristics, number of training sessions and the sequence of stimulation.
Collapse
Affiliation(s)
- Di Wu
- Department of Medical Psychology, Air Force Medical University, Xi’an, China
| | - Yifan Wang
- Department of Medical Psychology, Air Force Medical University, Xi’an, China
| | - Na Liu
- Department of Nursing, Air Force Medical University, Xi’an, China
| | - Panhui Wang
- Department of Medical Psychology, Air Force Medical University, Xi’an, China
| | - Kewei Sun
- Department of Medical Psychology, Air Force Medical University, Xi’an, China
| | - Wei Xiao
- Department of Medical Psychology, Air Force Medical University, Xi’an, China
- *Correspondence: Wei Xiao,
| |
Collapse
|
12
|
Battaglini L, Di Ponzio M, Ghiani A, Mena F, Santacesaria P, Casco C. Vision recovery with perceptual learning and non-invasive brain stimulation: Experimental set-ups and recent results, a review of the literature. Restor Neurol Neurosci 2022; 40:137-168. [PMID: 35964213 DOI: 10.3233/rnn-221261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Vision is the sense which we rely on the most to interact with the environment and its integrity is fundamental for the quality of our life. However, around the globe, more than 1 billion people are affected by debilitating vision deficits. Therefore, finding a way to treat (or mitigate) them successfully is necessary. OBJECTIVE This narrative review aims to examine options for innovative treatment of visual disorders (retinitis pigmentosa, macular degeneration, optic neuropathy, refractory disorders, hemianopia, amblyopia), especially with Perceptual Learning (PL) and Electrical Stimulation (ES). METHODS ES and PL can enhance visual abilities in clinical populations, inducing plastic changes. We describe the experimental set-ups and discuss the results of studies using ES or PL or their combination in order to suggest, based on literature, which treatment is the best option for each clinical condition. RESULTS Positive results were obtained using ES and PL to enhance visual functions. For example, repetitive transorbital Alternating Current Stimulation (rtACS) appeared as the most effective treatment for pre-chiasmatic disorders such as optic neuropathy. A combination of transcranial Direct Current Stimulation (tDCS) and visual training seems helpful for people with hemianopia, while transcranial Random Noise Stimulation (tRNS) makes visual training more efficient in people with amblyopia and mild myopia. CONCLUSIONS This narrative review highlights the effect of different ES montages and PL in the treatment of visual disorders. Furthermore, new options for treatment are suggested. It is noteworthy to mention that, in some cases, unclear results emerged and others need to be more deeply investigated.
Collapse
Affiliation(s)
- Luca Battaglini
- Department of General Psychology, University of Padova, Italy.,Centro di Ateneo dei Servizi Clinici Universitari Psicologici (SCUP), University of Padova, Padova, Italy.,Neuro.Vis.U.S, University of Padova, Padova, Italy
| | - Michele Di Ponzio
- Department of General Psychology, University of Padova, Italy.,Istituto di Neuroscienze, Florence, Italy
| | - Andrea Ghiani
- Department of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, the Netherlands
| | - Federica Mena
- Department of General Psychology, University of Padova, Italy
| | | | - Clara Casco
- Department of General Psychology, University of Padova, Italy.,Centro di Ateneo dei Servizi Clinici Universitari Psicologici (SCUP), University of Padova, Padova, Italy.,Neuro.Vis.U.S, University of Padova, Padova, Italy
| |
Collapse
|
13
|
Rassia KEK, Moutoussis K, Pezaris JS. Reading text works better than watching videos to improve acuity in a simulation of artificial vision. Sci Rep 2022; 12:12953. [PMID: 35902596 PMCID: PMC9334451 DOI: 10.1038/s41598-022-10719-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/12/2022] [Indexed: 12/03/2022] Open
Abstract
Simulated artificial vision is used in visual prosthesis design to answer questions about device usability. We previously reported a striking increase in equivalent visual acuity with daily use of a simulation of artificial vision in an active task, reading sentences, that required high levels of subject engagement, but passive activities are more likely to dominate post-implant experience. Here, we investigated the longitudinal effects of a passive task, watching videos. Eight subjects used a simulation of a thalamic visual prosthesis with 1000 phosphenes to watch 23 episodes of classic American television in daily, 25-min sessions, for a period of 1 month with interspersed reading tests that quantified reading accuracy and reading speed. For reading accuracy, we found similar dynamics to the early part of the learning process in our previous report, here leading to an improvement in visual acuity of 0.15 ± 0.05 logMAR. For reading speed, however, no change was apparent by the end of training. We found that single reading sessions drove about twice the improvement in acuity of single video sessions despite being only half as long. We conclude that while passive viewing tasks may prove useful for post-implant rehabilitation, active tasks are likely to be preferable.
Collapse
Affiliation(s)
- Katerina Eleonora K Rassia
- Cognitive Science Laboratory, Department of History and Philosophy of Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantinos Moutoussis
- Cognitive Science Laboratory, Department of History and Philosophy of Science, National and Kapodistrian University of Athens, Athens, Greece
| | - John S Pezaris
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA. .,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
14
|
Kwon S, Fahrenthold BK, Cavanaugh MR, Huxlin KR, Mitchell JF. Perceptual restoration fails to recover unconscious processing for smooth eye movements after occipital stroke. eLife 2022; 11:67573. [PMID: 35730931 PMCID: PMC9255960 DOI: 10.7554/elife.67573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/21/2022] [Indexed: 11/28/2022] Open
Abstract
The visual pathways that guide actions do not necessarily mediate conscious perception. Patients with primary visual cortex (V1) damage lose conscious perception but often retain unconscious abilities (e.g. blindsight). Here, we asked if saccade accuracy and post-saccadic following responses (PFRs) that automatically track target motion upon saccade landing are retained when conscious perception is lost. We contrasted these behaviors in the blind and intact fields of 11 chronic V1-stroke patients, and in 8 visually intact controls. Saccade accuracy was relatively normal in all cases. Stroke patients also had normal PFR in their intact fields, but no PFR in their blind fields. Thus, V1 damage did not spare the unconscious visual processing necessary for automatic, post-saccadic smooth eye movements. Importantly, visual training that recovered motion perception in the blind field did not restore the PFR, suggesting a clear dissociation between pathways mediating perceptual restoration and automatic actions in the V1-damaged visual system.
Collapse
Affiliation(s)
- Sunwoo Kwon
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, Berkeley, United States
| | | | - Matthew R Cavanaugh
- Center for Visual Science, University of Rochester, Rochester, United States
| | - Krystel R Huxlin
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, United States
| | - Jude F Mitchell
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, United States
| |
Collapse
|
15
|
Schmid D, Schneider S, Schenk T. How to test blindsight without light-scatter artefacts? Neuropsychologia 2022; 173:108308. [PMID: 35716799 DOI: 10.1016/j.neuropsychologia.2022.108308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 06/01/2022] [Accepted: 06/13/2022] [Indexed: 11/27/2022]
Abstract
Light-scatter artefacts are a methodological problem in testing residual visual capacities (RVCs), for instance blindsight, in patients with homonymous visual field defects (HVFDs). The term light-scatter artefact describes the phenomenon that light from targets directed towards the HVFD can stray into the sighted visual field. This might enable an observer to respond correctly to information directed at her blind field despite the fact that she is unable to process that information in the blind field itself. In this manuscript, we present a review of the relevance of light-scatter in visual neuroscience, discuss factors that influence the impact of light-scatter and evaluate means to test for light-scatter artefacts. Furthermore, we present findings from an empirical study that was aimed at developing tests for RVCs that are free of light-scatter artefacts. Previous studies on light scatter only used small sample sizes and equipment that is no longer in use. Hence, their results cannot be generalized to future experiments making it necessary to run laborious light-scatter tests for every new study on RVCs. To avoid this, we hereby start a pool of stimuli and paradigms which demonstrably do not elicit light-scatter artefacts. To this end, we investigated 21 healthy young participants in three frequently used RVC-paradigms: (1) temporal 2AFC task, (2) movement direction discrimination, and (3) redundant target paradigm. For each paradigm, we applied the blind-spot method. But first, we had to establish that our testing paradigm was sufficiently sensitive to detect light-scatter artefacts. For this, we used conditions that are known to produce strong light scatter and a paradigm that is very sensitive to such effects. Specifically, we presented white targets on a black background in a dark room. The stimuli were presented to observers' blind spot. To check for light-scatter artefacts, we used a target-detection task in a temporal 2AFC format. We obtained clear light-scatter artefacts. Participants produced reliably above-chance detection performance under these conditions. The other two luminance conditions, measured in an illuminated room, did not produce light-scatter artefacts. Accuracy in the temporal 2AFC task was at chance level for white targets on a grey background at the blind-spot position. Additionally, black targets on a grey background avoided light-scatter artefacts in all three RVC-paradigms. In future, researchers can apply these stimulus and illumination conditions when using one of the three above paradigms in their studies. Using these conditions, they will be able to avoid light-scatter artefacts without having to perform their own blind-spot tests.
Collapse
Affiliation(s)
- Doris Schmid
- Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802, Munich, Germany.
| | - Sebastian Schneider
- Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802, Munich, Germany.
| | - Thomas Schenk
- Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802, Munich, Germany.
| |
Collapse
|
16
|
Cavanaugh MR, Tadin D, Carrasco M, Huxlin KR. Benefits of Endogenous Spatial Attention During Visual Double-Training in Cortically-Blinded Fields. Front Neurosci 2022; 16:771623. [PMID: 35495043 PMCID: PMC9046589 DOI: 10.3389/fnins.2022.771623] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 03/08/2022] [Indexed: 12/12/2022] Open
Abstract
Recovery of visual discrimination thresholds inside cortically-blinded (CB) fields is most commonly attained at a single, trained location at a time, with iterative progress deeper into the blind field as performance improves over several months. As such, training is slow, inefficient, burdensome, and often frustrating for patients. Here, we investigated whether double-location training, coupled with a covert spatial-attention (SA) pre-cue, could improve the efficiency of training. Nine CB participants completed a randomized, training assignment with either a spatial attention or neutral pre-cue. All trained for a similar length of time on a fine direction discrimination task at two blind field locations simultaneously. Training stimuli and tasks for both cohorts were identical, save for the presence of a central pre-cue, to manipulate endogenous (voluntary) SA, or a Neutral pre-cue. Participants in the SA training cohort demonstrated marked improvements in direction discrimination thresholds, albeit not to normal/intact-field levels; participants in the Neutral training cohort remained impaired. Thus, double-training within cortically blind fields, when coupled with SA pre-cues can significantly improve direction discrimination thresholds at two locations simultaneously, offering a new method to improve performance and reduce the training burden for CB patients. Double-training without SA pre-cues revealed a hitherto unrecognized limitation of cortically-blind visual systems’ ability to improve while processing two stimuli simultaneously. These data could potentially explain why exposure to the typically complex visual environments encountered in everyday life is insufficient to induce visual recovery in CB patients. It is hoped that these new insights will direct both research and therapeutic developments toward methods that can attain better, faster recovery of vision in CB fields.
Collapse
Affiliation(s)
- Matthew R. Cavanaugh
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, United States
| | - Duje Tadin
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, United States
- Department of Brain and Cognitive Sciences and Center for Visual Science, University of Rochester, Rochester, NY, United States
| | - Marisa Carrasco
- Department of Psychology and Center for Neural Science, New York University, New York, NY, United States
| | - Krystel R. Huxlin
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, United States
- Department of Brain and Cognitive Sciences and Center for Visual Science, University of Rochester, Rochester, NY, United States
- *Correspondence: Krystel R. Huxlin,
| |
Collapse
|
17
|
Awada A, Bakhtiari S, Legault C, Odier C, Pack CC. Training with optic flow stimuli promotes recovery in cortical blindness. Restor Neurol Neurosci 2022; 40:1-16. [PMID: 35213337 DOI: 10.3233/rnn-211223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Cortical blindness is a form of severe vision loss that is caused by damage to the primary visual cortex (V1) or its afferents. This condition has devastating effects on quality of life and independence. While there are few treatments currently available, accumulating evidence shows that certain visual functions can be restored with appropriate perceptual training: Stimulus sensitivity can be increased within portions of the blind visual field. However, this increased sensitivity often remains highly specific to the trained stimulus, limiting the overall improvement in visual function. OBJECTIVE Recent advances in the field of perceptual learning show that such specificity can be overcome with training paradigms that leverage the properties of higher-level visual cortical structures, which have greater capacity to generalize across stimulus positions and features. This targeting can be accomplished by using more complex training stimuli that elicit robust responses in these visual structures. METHODS We trained cortically blind subjects with a complex optic flow motion stimulus that was presented in a location of their blind field. Participants were instructed to train with the stimulus at home for approximately 30 minutes per day. Once performance plateaued, the stimulus was moved deeper into the blind field. A battery of pre- and post-training measures, with careful eye tracking, was performed to quantify the improvements. RESULTS We show that 1) optic flow motion discrimination can be relearned in cortically blind fields; 2) training with an optic flow stimulus can lead to improvements that transfer to different tasks and untrained locations; and 3) such training leads to a significant expansion of the visual field. The observed expansion of the visual field was present even when eye movements were carefully controlled. Finally, we show that regular training is critical for improved visual function, as sporadic training reduced the benefits of training, even when the total numbers of training sessions were equated. CONCLUSIONS These findings are consistent with the hypothesis that complex training stimuli can improve outcomes in cortical blindness, provided that patients adhere to a regular training regimen. Nevertheless, such interventions remain limited in their ability to restore functional vision.
Collapse
Affiliation(s)
- Asmara Awada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Shahab Bakhtiari
- Department of Computer Science, McGill University, Montreal, Canada
| | - Catherine Legault
- McGill University Health Center (MUHC), Montreal, Canada.,Montreal Neurological Institute and Hospital, Montreal, Canada
| | - Celine Odier
- Neurovascular Health Program, Department of Medicine (Neurology), Centre Hospitalier de l'Universite de Montreal, Montreal, Canada
| | - Christopher C Pack
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| |
Collapse
|
18
|
Rehabilitation of visual perception in cortical blindness. HANDBOOK OF CLINICAL NEUROLOGY 2022; 184:357-373. [PMID: 35034749 DOI: 10.1016/b978-0-12-819410-2.00030-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Blindness is a common sequela after stroke affecting the primary visual cortex, presenting as a contralesional, homonymous, visual field cut. This can occur unilaterally or, less commonly, bilaterally. While it has been widely assumed that after a brief period of spontaneous improvement, vision loss becomes stable and permanent, accumulating data show that visual training can recover some of the vision loss, even long after the stroke. Here, we review the different approaches to rehabilitation employed in adult-onset cortical blindness (CB), focusing on visual restoration methods. Most of this work was conducted in chronic stroke patients, partially restoring visual discrimination and luminance detection. However, to achieve this, patients had to train for extended periods (usually many months), and the vision restored was not entirely normal. Several adjuvants to training such as noninvasive, transcranial brain stimulation, and pharmacology are starting to be investigated for their potential to increase the efficacy of training in CB patients. However, these approaches are still exploratory and require considerably more research before being adopted. Nonetheless, having established that the adult visual system retains the capacity for restorative plasticity, attention recently turned toward the subacute poststroke period. Drawing inspiration from sensorimotor stroke rehabilitation, visual training was recently attempted for the first time in subacute poststroke patients. It improved vision faster, over larger portions of the blind field, and for a larger number of visual discrimination abilities than identical training initiated more than 6 months poststroke (i.e., in the chronic period). In conclusion, evidence now suggests that visual neuroplasticity after occipital stroke can be reliably recruited by a range of visual training approaches. In addition, it appears that poststroke visual plasticity is dynamic, with a critical window of opportunity in the early postdamage period to attain more rapid, more extensive recovery of a larger set of visual perceptual abilities.
Collapse
|
19
|
Pandey A, Neupane S, Adhikary S, Vaidya K, Pack CC. Cortical visual impairment at birth can be improved rapidly by vision training in adulthood: A case study. Restor Neurol Neurosci 2022; 40:261-270. [PMID: 37038774 DOI: 10.3233/rnn-221294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
BACKGROUND Cortical visual impairment (CVI) is a severe loss of visual function caused by damage to the visual cortex or its afferents, often as a consequence of hypoxic insults during birth. It is one of the leading causes of vision loss in children, and it is most often permanent. OBJECTIVE Several studies have demonstrated limited vision restoration in adults who trained on well-controlled psychophysical tasks, after acquiring CVI late in life. Other studies have shown improvements in children who underwent vision training. However, little is known about the prospects for the large number of patients who acquired CVI at birth but received no formal therapy as children. METHODS We, therefore, conducted a proof-of-principle study in one CVI patient long after the onset of cortical damage (age 18), to test the training speed, efficacy and generalizability of vision rehabilitation using protocols that had previously proven successful in adults. The patient trained at home and in the laboratory, on a psychophysical task that required discrimination of complex motion stimuli presented in the blind field. Visual function was assessed before and after training, using perimetric measures, as well as a battery of psychophysical tests. RESULTS The patient showed remarkably rapid improvements on the training task, with performance going from chance to 80% correct over the span of 11 sessions. With further training, improved vision was found for untrained stimuli and for perimetric measures of visual sensitivity. Some, but not all, of these performance gains were retained upon retesting after one year. CONCLUSIONS These results suggest that existing vision rehabilitation programs can be highly effective in adult patients who acquired CVI at a young age. Validation with a large sample size is critical, and future work should also focus on improving the usability and accessibility of these programs for younger patients.
Collapse
Affiliation(s)
- Ashim Pandey
- Department of Neuro-ophthalmology, Tilganga Institute of Ophthalmology, Kathmandu, Nepal
| | - Sujaya Neupane
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Boston, USA
| | - Srijana Adhikary
- Department of Pediatric Ophthalmology and Strabismus, Tilganga Institute of Ophthalmology, Kathmandu, Nepal
| | - Keepa Vaidya
- Department of Neuro-ophthalmology, Tilganga Institute of Ophthalmology, Kathmandu, Nepal
| | - Christopher C Pack
- Department of Neurology & Neurosurgery, McGill University, Montreal, Canada
| |
Collapse
|
20
|
Contò F, Edwards G, Tyler S, Parrott D, Grossman E, Battelli L. Attention network modulation via tRNS correlates with attention gain. eLife 2021; 10:e63782. [PMID: 34826292 PMCID: PMC8626087 DOI: 10.7554/elife.63782] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/05/2021] [Indexed: 12/21/2022] Open
Abstract
Transcranial random noise stimulation (tRNS) can enhance vision in the healthy and diseased brain. Yet, the impact of multi-day tRNS on large-scale cortical networks is still unknown. We investigated the impact of tRNS coupled with behavioral training on resting-state functional connectivity and attention. We trained human subjects for 4 consecutive days on two attention tasks, while receiving tRNS over the intraparietal sulci, the middle temporal areas, or Sham stimulation. We measured resting-state functional connectivity of nodes of the dorsal and ventral attention network (DVAN) before and after training. We found a strong behavioral improvement and increased connectivity within the DVAN after parietal stimulation only. Crucially, behavioral improvement positively correlated with connectivity measures. We conclude changes in connectivity are a marker for the enduring effect of tRNS upon behavior. Our results suggest that tRNS has strong potential to augment cognitive capacity in healthy individuals and promote recovery in the neurological population.
Collapse
Affiliation(s)
- Federica Contò
- Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di TecnologiaRoveretoItaly
- Center for Mind/Brain Sciences, University of TrentoRoveretoItaly
| | - Grace Edwards
- Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di TecnologiaRoveretoItaly
- Department of Psychology, Harvard UniversityCambridgeUnited States
| | - Sarah Tyler
- Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di TecnologiaRoveretoItaly
- Butte CollegeOrovilleUnited States
| | - Danielle Parrott
- Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di TecnologiaRoveretoItaly
- Center for Mind/Brain Sciences, University of TrentoRoveretoItaly
| | - Emily Grossman
- Department of Cognitive Sciences, University of California, IrvineIrvineUnited States
| | - Lorella Battelli
- Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di TecnologiaRoveretoItaly
- Center for Mind/Brain Sciences, University of TrentoRoveretoItaly
- Department of Psychology, Harvard UniversityCambridgeUnited States
- Department of Neurology, Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel, Deaconess Medical Center, Harvard Medical SchoolBostonUnited States
| |
Collapse
|
21
|
Spared perilesional V1 activity underlies training-induced recovery of luminance detection sensitivity in cortically-blind patients. Nat Commun 2021; 12:6102. [PMID: 34671032 PMCID: PMC8528839 DOI: 10.1038/s41467-021-26345-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 09/29/2021] [Indexed: 11/19/2022] Open
Abstract
Damage to the primary visual cortex (V1) causes homonymous visual-field loss long considered intractable. Multiple studies now show that perceptual training can restore visual functions in chronic cortically-induced blindness (CB). A popular hypothesis is that training can harness residual visual functions by recruiting intact extrageniculostriate pathways. Training may also induce plastic changes within spared regions of the damaged V1. Here, we link changes in luminance detection sensitivity with retinotopic fMRI activity before and after visual discrimination training in eleven patients with chronic, stroke-induced CB. We show that spared V1 activity representing perimetrically-blind locations prior to training predicts the amount of training-induced recovery of luminance detection sensitivity. Additionally, training results in an enlargement of population receptive fields in perilesional V1, which increases blind-field coverage and may support further recovery with subsequent training. These findings uncover fundamental changes in perilesional V1 cortex underlying training-induced restoration of conscious luminance detection sensitivity in CB. In humans, stroke damage to V1 causes large visual field defects. Spared V1 activity prior to training predicts the amount of training-induced recovery in luminance detection sensitivity. Moreover, visual training changes population receptive field properties within residual V1 circuits.
Collapse
|
22
|
Fahrenthold BK, Cavanaugh MR, Jang S, Murphy AJ, Ajina S, Bridge H, Huxlin KR. Optic Tract Shrinkage Limits Visual Restoration After Occipital Stroke. Stroke 2021; 52:3642-3650. [PMID: 34266305 PMCID: PMC8545836 DOI: 10.1161/strokeaha.121.034738] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Supplemental Digital Content is available in the text. Background and Purpose: Damage to the adult primary visual cortex (V1) causes vision loss in the contralateral visual hemifield, initiating a process of trans-synaptic retrograde degeneration. The present study examined functional implications of this process, asking if degeneration impacted the amount of visual recovery attainable from visual restoration training in chronic patients, and if restoration training impacted optic tract (OT) shrinkage. Methods: Magnetic resonance imaging was used to measure OT volumes bilaterally in 36 patients with unilateral occipital stroke. From OT volumes, we computed laterality indices (LI), estimating the stroke-induced OT shrinkage in each case. A subset of these chronic patients (n=14, 13±6 months poststroke) underwent an average of nearly 1 year of daily visual restoration training, which repeatedly stimulated vision in their blind field. The amount of visual field recovery was quantified using Humphrey perimetry, and post training magnetic resonance imaging was used to assess the impact of training on OT shrinkage. Results: OT LI was correlated with time since stroke: it was close to 0 (no measurable OT shrinkage) in subacute participants (<6 months poststroke) while chronic participants (>6 months poststroke) exhibited LI >0, but with significant variability. Visual training did not systematically alter LI, but chronic patients with baseline LI≈0 (no OT shrinkage) exhibited greater visual field recovery than those with LI>0. Conclusions: Unilateral OT shrinkage becomes detectable with magnetic resonance imaging by ≈7 months poststroke, albeit with significant interindividual variability. Although visual restoration training did not alter the amount of degeneration already sustained, OT shrinkage appeared to serve as a biomarker of the potential for training-induced visual recovery in chronic cortically blind patients.
Collapse
Affiliation(s)
- Berkeley K. Fahrenthold
- Flaum Eye Institute (B.K.F., M.R.C., S.J., K.R.H.), University of Rochester, NY. Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom. Department of Neurorehabilitation and Therapy Services, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
| | - Matthew R. Cavanaugh
- Flaum Eye Institute (B.K.F., M.R.C., S.J., K.R.H.), University of Rochester, NY. Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom. Department of Neurorehabilitation and Therapy Services, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
| | - Subin Jang
- Flaum Eye Institute (B.K.F., M.R.C., S.J., K.R.H.), University of Rochester, NY. Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom. Department of Neurorehabilitation and Therapy Services, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
| | - Allison J. Murphy
- Neuroscience Graduate Program (A.J.M.), University of Rochester, NY. Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom. Department of Neurorehabilitation and Therapy Services, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
| | | | | | - Krystel R. Huxlin
- Flaum Eye Institute (B.K.F., M.R.C., S.J., K.R.H.), University of Rochester, NY. Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom. Department of Neurorehabilitation and Therapy Services, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
| |
Collapse
|
23
|
Ajina S, Jünemann K, Sahraie A, Bridge H. Increased Visual Sensitivity and Occipital Activity in Patients With Hemianopia Following Vision Rehabilitation. J Neurosci 2021; 41:5994-6005. [PMID: 34035137 PMCID: PMC8276743 DOI: 10.1523/jneurosci.2790-20.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/22/2021] [Accepted: 03/26/2021] [Indexed: 11/21/2022] Open
Abstract
Hemianopia, loss of vision in half of the visual field, results from damage to the visual pathway posterior to the optic chiasm. Despite negative effects on quality of life, few rehabilitation options are currently available. Recently, several long-term training programs have been developed that show visual improvement within the blind field, although little is known of the underlying neural changes. Here, we have investigated functional and structural changes in the brain associated with visual rehabilitation. Seven human participants with occipital lobe damage enrolled in a visual training program to distinguish which of two intervals contained a drifting Gabor patch presented within the blind field. Participants performed ∼25 min of training each day for 3-6 months and undertook psychophysical tests and a magnetic resonance imaging scan before and after training. A control group undertook psychophysical tests before and after an equivalent period without training. Participants who were not at ceiling on baseline tests showed on average 9.6% improvement in Gabor detection, 8.3% in detection of moving dots, and 9.9% improvement in direction discrimination after training. Importantly, psychophysical improvement only correlated with improvement in Humphrey perimetry in the trained region of the visual field. Whole-brain analysis showed an increased neural response to moving stimuli in the blind visual field in motion area V5/hMT. Using a region-of-interest approach, training had a significant effect on the blood oxygenation level-dependent signal compared with baseline. Moreover, baseline V5/hMT activity was correlated to the amount of improvement in visual sensitivity using psychophysical and perimetry tests. This study, identifying a critical role for V5/hMT in boosting visual function, may allow us to determine which patients may benefit most from training and design adjunct interventions to increase training effects.SIGNIFICANCE STATEMENT Homonymous visual field loss is a common consequence of brain injury and is estimated to affect more than 230,000 people in the United Kingdom. Despite its high prevalence and well-described impact on quality of life, treatments to improve visual sensitivity remain experimental, and deficits are considered permanent after 6 months. Our study shows that behavioral changes following vision rehabilitation are associated with enhanced visually-evoked occipital activity to stimuli in the blind visual field. Unlike previous behavioral studies, we observe clinical changes that are specific to the trained region of vision. This lends significant weight to such training paradigms and offers a mechanism by which visual function can be improved despite damage to the primary visual pathway.
Collapse
Affiliation(s)
- Sara Ajina
- Department of Neurorehabilitation and Therapy Services, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom
- Wellcome Centre for Integrative Neuroimaging, Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Kristin Jünemann
- Wellcome Centre for Integrative Neuroimaging, Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, United Kingdom
- Division of Clinical Psychology and Sexual Medicine, Department of Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical School, 30635 Hannover, Germany
| | - Arash Sahraie
- School of Psychology, University of Aberdeen, Kings College, Old Aberdeen AB24 3FX, United Kingdom
| | - Holly Bridge
- Wellcome Centre for Integrative Neuroimaging, Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, United Kingdom
| |
Collapse
|
24
|
Salamanca-Giron RF, Raffin E, Zandvliet SB, Seeber M, Michel CM, Sauseng P, Huxlin KR, Hummel FC. Enhancing visual motion discrimination by desynchronizing bifocal oscillatory activity. Neuroimage 2021; 240:118299. [PMID: 34171500 DOI: 10.1016/j.neuroimage.2021.118299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/11/2021] [Accepted: 06/20/2021] [Indexed: 11/17/2022] Open
Abstract
Visual motion discrimination involves reciprocal interactions in the alpha band between the primary visual cortex (V1) and mediotemporal areas (V5/MT). We investigated whether modulating alpha phase synchronization using individualized multisite transcranial alternating current stimulation (tACS) over V5 and V1 regions would improve motion discrimination. We tested 3 groups of healthy subjects with the following conditions: (1) individualized In-Phase V1alpha-V5alpha tACS (0° lag), (2) individualized Anti-Phase V1alpha-V5alpha tACS (180° lag) and (3) sham tACS. Motion discrimination and EEG activity were recorded before, during and after tACS. Performance significantly improved in the Anti-Phase group compared to the In-Phase group 10 and 30 min after stimulation. This result was explained by decreases in bottom-up alpha-V1 gamma-V5 phase-amplitude coupling. One possible explanation of these results is that Anti-Phase V1alpha-V5alpha tACS might impose an optimal phase lag between stimulation sites due to the inherent speed of wave propagation, hereby supporting optimized neuronal communication.
Collapse
Affiliation(s)
- Roberto F Salamanca-Giron
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Estelle Raffin
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Sarah B Zandvliet
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Martin Seeber
- Functional Brain Mapping Lab, Department of Fundamental Neurosciences, University of Geneva, Campus Biotech, Chemin des Mines 9, 1202, Geneva, Switzerland
| | - Christoph M Michel
- Functional Brain Mapping Lab, Department of Fundamental Neurosciences, University of Geneva, Campus Biotech, Chemin des Mines 9, 1202, Geneva, Switzerland; Lemanic Biomedical Imaging Centre (CIBM), Lausanne, Geneva, Switzerland
| | - Paul Sauseng
- Department of Psychology, LMU Munich, Leopoldstr. 13, Munich 80802, Germany
| | - Krystel R Huxlin
- The Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Friedhelm C Hummel
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland; Clinical Neuroscience, University of Geneva Medical School, Geneva, Switzerland.
| |
Collapse
|
25
|
Abstract
Visual perceptual learning (VPL) is an improvement in visual function following training. Although the practical utility of VPL was once thought to be limited by its specificity to the precise stimuli used during training, more recent work has shown that such specificity can be overcome with appropriate training protocols. In contrast, relatively little is known about the extent to which VPL exhibits motor specificity. Previous studies have yielded mixed results. In this work, we have examined the effector specificity of VPL by training observers on a motion discrimination task that maintains the same visual stimulus (drifting grating) and task structure, but that requires different effectors to indicate the response (saccade vs. button press). We find that, in these conditions, VPL transfers fully between a manual and an oculomotor response. These results are consistent with the idea that VPL entails the learning of a decision rule that can generalize across effectors.
Collapse
Affiliation(s)
- Asmara Awada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.,
| | - Shahab Bakhtiari
- Department of Computer Science, McGill University, Montreal, Canada.,
| | - Christopher C Pack
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.,
| |
Collapse
|
26
|
Hagan MA, Chaplin TA, Huxlin KR, Rosa MGP, Lui LL. Altered Sensitivity to Motion of Area MT Neurons Following Long-Term V1 Lesions. Cereb Cortex 2021; 30:451-464. [PMID: 31211357 DOI: 10.1093/cercor/bhz096] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 02/04/2023] Open
Abstract
Primates with primary visual cortex (V1) damage often retain residual motion sensitivity, which is hypothesized to be mediated by middle temporal area (MT). MT neurons continue to respond to stimuli shortly after V1 lesions; however, experimental and clinical studies of lesion-induced plasticity have shown that lesion effects can take several months to stabilize. It is unknown what physiological changes occur in MT and whether neural responses persist long after V1 damage. We recorded neuronal responses in MT to moving dot patterns in adult marmoset monkeys 6-12 months after unilateral V1 lesions. In contrast to results obtained shortly after V1 lesions, we found that fewer MT neurons were direction selective, including neurons expected to still receive projections from remaining parts of V1. The firing rates of most cells increased with increases in motion strength, regardless of stimulus direction. Furthermore, firing rates were higher and more variable than in control MT cells. To test whether these observations could be mechanistically explained by underlying changes in neural circuitry, we created a network model of MT. We found that a local imbalance of inhibition and excitation explained the observed firing rate changes. These results provide the first insights into functional implications of long-term plasticity in MT following V1 lesions.
Collapse
Affiliation(s)
- Maureen A Hagan
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia
| | - Tristan A Chaplin
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia.,Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, 25 Howland Street, London W1T 4JG, United Kingdom
| | - Krystel R Huxlin
- Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
| | - Marcello G P Rosa
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia
| | - Leo L Lui
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia
| |
Collapse
|
27
|
Shibuki K, Yokota T, Hirasawa A, Tamura D, Hasegawa S, Nakajima T. Visual Field Test With Gaze Check Tasks: Application in a Homonymous Hemianopic Patient Unaware of the Visual Defects. Front Neurol 2021; 12:682761. [PMID: 34149606 PMCID: PMC8206790 DOI: 10.3389/fneur.2021.682761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/11/2021] [Indexed: 11/13/2022] Open
Abstract
Gaze control is required for applying visual stimuli to a particular area of the visual field. We developed a visual field test with gaze check tasks to investigate hemianopia. In this test, participants must report the presence or absence of visual stimuli when a small object at the fixation point vibrates. Trials in the absence of visual stimuli were used as gaze check tasks, since the vibration could be observed only when the gaze was directed at the fixation point. We evaluated the efficacy of our test in four control participants and one patient with homonymous hemianopia who was unaware of the defects in the left visual field. This patient presented hemianopia in the test with gaze check tasks, but not when the gaze check tasks were omitted. The patient showed spontaneous gaze movements from the fixation point to the upper left direction, as well as scanning of the left visual field during the test without gaze check tasks. Thus, we concluded that the visual defects in this patient were compensated in daily life by spontaneous eye movements coordinated with visual information processing. The present results show the usefulness of the visual field test with gaze check tasks.
Collapse
Affiliation(s)
- Katsuei Shibuki
- Department of Clinical Laboratory, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan.,Brain Research Institute, Niigata University, Asahi-Machi, Chuo-Ku, Niigata, Japan
| | - Tsuyoshi Yokota
- Department of Rehabilitation, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan
| | - Akane Hirasawa
- Department of Rehabilitation, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan
| | - Daisuke Tamura
- Department of Rehabilitation, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan
| | - Shin Hasegawa
- Department of Internal Medicine, Kashiwazaki General Hospital and Medical Center,Kashiwazaki, Japan
| | - Takashi Nakajima
- Department of Internal Medicine, Kashiwazaki General Hospital and Medical Center,Kashiwazaki, Japan.,Department of Neurology, National Hospital Organization Niigata National Hospital, Kashiwazaki, Japan
| |
Collapse
|
28
|
Elshout JA, Bergsma DP, van den Berg AV, Haak KV. Functional MRI of visual cortex predicts training-induced recovery in stroke patients with homonymous visual field defects. NEUROIMAGE-CLINICAL 2021; 31:102703. [PMID: 34062384 PMCID: PMC8173295 DOI: 10.1016/j.nicl.2021.102703] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 12/28/2022]
Abstract
Damage to the visual brain typically leads to vision loss. Vision loss may be partially recovered with visual restitution training (VRT) Cortical responses to visual stimulation do not always lead to visual awareness. A mismatch between Humphrey and neural perimetry predicts training outcome. This finding has important implications for better rehabilitation strategies.
Post-chiasmatic damage to the visual system leads to homonymous visual field defects (HVDs), which can severely interfere with daily life activities. Visual Restitution Training (VRT) can recover parts of the affected visual field in patients with chronic HVDs, but training outcome is variable. An untested hypothesis suggests that training potential may be largest in regions with ‘neural reserve’, where cortical responses to visual stimulation do not lead to visual awareness as assessed by Humphrey perimetry—a standard behavioural visual field test. Here, we tested this hypothesis in a sample of twenty-seven hemianopic stroke patients, who participated in an assiduous 80-hour VRT program. For each patient, we collected Humphrey perimetry and wide-field fMRI-based retinotopic mapping data prior to training. In addition, we used Goal Attainment Scaling to assess whether personal activities in daily living improved. After training, we assessed with a second Humphrey perimetry measurement whether the visual field was improved and evaluated which personal goals were attained. Confirming the hypothesis, we found significantly larger improvements of visual sensitivity at field locations with neural reserve. These visual field improvements implicated both regions in primary visual cortex and higher order visual areas. In addition, improvement in daily life activities correlated with the extent of visual field enlargement. Our findings are an important step toward understanding the mechanisms of visual restitution as well as predicting training efficacy in stroke patients with chronic hemianopia.
Collapse
Affiliation(s)
- J A Elshout
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - D P Bergsma
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - A V van den Berg
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - K V Haak
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands.
| |
Collapse
|
29
|
Is the primary visual cortex necessary for blindsight-like behavior? Review of transcranial magnetic stimulation studies in neurologically healthy individuals. Neurosci Biobehav Rev 2021; 127:353-364. [PMID: 33965459 DOI: 10.1016/j.neubiorev.2021.04.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 12/20/2022]
Abstract
The visual pathways that bypass the primary visual cortex (V1) are often assumed to support visually guided behavior in humans in the absence of conscious vision. This conclusion is largely based on findings on patients: V1 lesions cause blindness but sometimes leave some visually guided behaviors intact-this is known as blindsight. With the aim of examining how well the findings on blindsight patients generalize to neurologically healthy individuals, we review studies which have tried to uncover transcranial magnetic stimulation (TMS) induced blindsight. In general, these studies have failed to demonstrate a completely unconscious blindsight-like capacity in neurologically healthy individuals. A possible exception to this is TMS-induced blindsight of stimulus presence or location. Because blindsight in patients is often associated with some form of introspective access to the visual stimulus, and blindsight may be associated with neural reorganization, we suggest that rather than revealing a dissociation between visually guided behavior and conscious seeing, blindsight may reflect preservation or partial recovery of conscious visual perception after the lesion.
Collapse
|
30
|
Rehabilitation of visual disorders. HANDBOOK OF CLINICAL NEUROLOGY 2021; 178:361-386. [PMID: 33832686 DOI: 10.1016/b978-0-12-821377-3.00015-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
While there is a long history of rehabilitation for motor deficits following cerebral lesions, less is known about our ability to improve visual deficits. Vision therapy, prisms, occluders, and filters have been advocated for patients with mild traumatic brain injury, on the premise that some of their symptoms may reflect abnormal visual or ocular motor function, but the evidence for their efficacy is modest. For hemianopia, attempts to restore vision have had unimpressive results, though it appears possible to generate blindsight through training. Strategic approaches that train more efficient use of visual search in hemianopia have shown consistent benefit in visual function, while prism aids may help some patients. There are many varieties of alexia. Strategic adaptation of saccades can improve hemianopic alexia, but there has been less work and mixed results for pure alexia, neglect dyslexia, attentional dyslexia, and the central dyslexias. A number of approaches have been tried in prosopagnosia, with recent studies of small groups suggesting that face perception of prosopagnosic subjects can be enhanced through perceptual learning.
Collapse
|
31
|
Saionz EL, Tadin D, Melnick MD, Huxlin KR. Functional preservation and enhanced capacity for visual restoration in subacute occipital stroke. Brain 2021; 143:1857-1872. [PMID: 32428211 DOI: 10.1093/brain/awaa128] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/30/2020] [Accepted: 03/01/2020] [Indexed: 01/18/2023] Open
Abstract
Stroke damage to the primary visual cortex (V1) causes a loss of vision known as hemianopia or cortically-induced blindness. While perimetric visual field improvements can occur spontaneously in the first few months post-stroke, by 6 months post-stroke, the deficit is considered chronic and permanent. Despite evidence from sensorimotor stroke showing that early injury responses heighten neuroplastic potential, to date, visual rehabilitation research has focused on patients with chronic cortically-induced blindness. Consequently, little is known about the functional properties of the post-stroke visual system in the subacute period, nor do we know if these properties can be harnessed to enhance visual recovery. Here, for the first time, we show that 'conscious' visual discrimination abilities are often preserved inside subacute, perimetrically-defined blind fields, but they disappear by ∼6 months post-stroke. Complementing this discovery, we now show that training initiated subacutely can recover global motion discrimination and integration, as well as luminance detection perimetry, just as it does in chronic cortically-induced blindness. However, subacute recovery was attained six times faster; it also generalized to deeper, untrained regions of the blind field, and to other (untrained) aspects of motion perception, preventing their degradation upon reaching the chronic period. In contrast, untrained subacutes exhibited spontaneous improvements in luminance detection perimetry, but spontaneous recovery of motion discriminations was never observed. Thus, in cortically-induced blindness, the early post-stroke period appears characterized by gradual-rather than sudden-loss of visual processing. Subacute training stops this degradation, and is far more efficient at eliciting recovery than identical training in the chronic period. Finally, spontaneous visual improvements in subacutes were restricted to luminance detection; discrimination abilities only recovered following deliberate training. Our findings suggest that after V1 damage, rather than waiting for vision to stabilize, early training interventions may be key to maximize the system's potential for recovery.
Collapse
Affiliation(s)
- Elizabeth L Saionz
- Flaum Eye Institute, University of Rochester, Rochester, NY, USA.,Medical Scientist Training Program, University of Rochester, Rochester, NY, USA
| | - Duje Tadin
- Flaum Eye Institute, University of Rochester, Rochester, NY, USA.,Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Michael D Melnick
- Flaum Eye Institute, University of Rochester, Rochester, NY, USA.,Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Krystel R Huxlin
- Flaum Eye Institute, University of Rochester, Rochester, NY, USA.,Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| |
Collapse
|
32
|
Maniglia M, Soler V, Trotter Y. Combining fixation and lateral masking training enhances perceptual learning effects in patients with macular degeneration. J Vis 2020; 20:19. [PMID: 33064123 PMCID: PMC7571291 DOI: 10.1167/jov.20.10.19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Macular degeneration (MD), a retinal disease affecting central vision, represents the leading cause of visual impairment in the Western world, and MD patients face severe limitations in daily activities like reading and face recognition. A common compensation strategy adopted by these patients involves the use of a region in the spared peripheral retina as a new fixation spot and oculomotor reference (preferred retinal locus, or PRL). Still, peripheral vision is characterized by poorer visual acuity, fixation stability, and larger crowding zones that further hinder processes like object recognition, visual search, and reading. Perceptual learning (PL) has been successfully used to improve visual acuity in mild visual conditions (e.g., presbyopia, amblyopia and myopia), but results in MD are less clear, often showing limited generalization of learning, unlike what is observed in a healthy population. A possible reason is the suboptimal fixation in the PRL that might prevent patients from processing the briefly presented training stimuli. Following this hypothesis, we trained five MD patients and four age- and eccentricity-matched controls with a protocol that combined contrast detection and a task previously used to train fixation stability. Results showed transfer of learning to crowding reduction, reading speed, and visual acuity in both MD patients and controls. These results suggest that in the case of central vision loss, PL training might benefit from the integration of oculomotor components to optimize the effect of training and promote transfer of learning to other visual functions.
Collapse
Affiliation(s)
- Marcello Maniglia
- UC Riverside, Riverside, CA, USA.,Université de Toulouse-UPS, Centre de Recherche Cerveau et Cognition, Toulouse, France.,Centre National de la Recherche Scientifique, Toulouse Cedex, France.,
| | - Vincent Soler
- Unité de rétine, consultation d'ophtalmologie, hôpital Pierre-Paul-Riquet, CHU de Toulouse, Toulouse Cedex, France.,
| | - Yves Trotter
- Université de Toulouse-UPS, Centre de Recherche Cerveau et Cognition, Toulouse, France.,Centre National de la Recherche Scientifique, Toulouse Cedex, France.,
| |
Collapse
|
33
|
|
34
|
Ge Q, Chen Z, Liu Z, Pan JS, Wen Y, Li J, Feng L, Yuan J, Deng D, Yu M. Quantifying Nasotemporal Asymmetry of Interocular Suppression in Alternating Strabismus After Correction. Invest Ophthalmol Vis Sci 2020; 61:6. [PMID: 32634203 PMCID: PMC7425725 DOI: 10.1167/iovs.61.8.6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 04/21/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose This study identifies and characterizes the nasotemporal hemifield difference of interocular suppression in subjects who have been successfully treated for strabismus. Methods Interocular suppression in the nasal and temporal hemifields were measured using two methods, namely, binocular phase combination and dichoptic motion coherence, both entailed suprathreshold stimuli. We tested 29 clinical subjects, who had strabismus (19 with exotropia and 10 with esotropia) but regained good ocular alignment (within 10 prism diopters) after surgical or refractive correction, and 10 control subjects. Results Both the hemifield binocular phase combination and the hemifield dichoptic motion coherence tests revealed similar nasotemporal asymmetry of interocular suppression. Subjects with previous exotropia showed deeper suppression in the nasal hemifield, and those with previous esotropia showed deeper suppression in the temporal hemifield. This finding was consistent with the hemifield suppression theory. Furthermore, there was deeper suppression but less imbalance of nasotemporal asymmetry in the hemifield dichoptic motion coherence test. Finally, clinical stereopsis and the nasotemporal asymmetry of suppression (P < 0.05 in both tests) were negatively correlated in subjects with previous exotropia and measurable stereopsis. Conclusions Hemifield asymmetry of interocular suppression in corrected strabismus can be measured by using static and dynamic suprathreshold stimuli. Thus, the evaluation of binocular vision in strabismus should focus on both the magnitude and the pattern of interocular suppression.
Collapse
Affiliation(s)
- Qingshu Ge
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Zidong Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Zitian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | | | - Yun Wen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jinrong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Lei Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Junpeng Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Daming Deng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
35
|
Huurneman B, Nienke Boonstra F, Goossens J. Specificity and retention of visual perceptual learning in young children with low vision. Sci Rep 2020; 10:8873. [PMID: 32483176 PMCID: PMC7264217 DOI: 10.1038/s41598-020-65789-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/06/2020] [Indexed: 11/09/2022] Open
Abstract
There is evidence that a pen-and-paper training based on perceptual learning principles improves near visual acuity in young children with visual impairment. The aim of the present study is to measure specificity and retention of its training effects during one year. Sixteen visually impaired children aged 4-8 years were divided in two age- and acuity-matched groups: an early (n = 9) and late treatment group (n = 7). Training consisted of 12 sessions (2× per week for 6 weeks). Studied variables were uncrowded and crowded binocular near visual acuity (40 cm), distance visual acuity (3.0 m) and fine motor skills (Beery VMI, subtest Motor Control). In the early treatment group, we measured at 0 months (pre-training), at 2 months (post-training), at 8 months (6 months post-training) and at 14 months (12 months post-training) since inclusion. In the late treatment group, three pre-training measurements were performed at 0, 2 and 8 months, and two measurements at 0 and 6 months post-training. In the short term, training improved uncrowded and crowded near visual acuity at 0.4 m by 0.13 ± 0.03 and 0.09 ± 0.03 logMAR, respectively (mean ± SEM). Training did not affect distance acuities or Beery scores. Learning effects on uncrowded and crowded near visual acuities remained intact 6-12 months after training. We conclude that the pen-and-paper training specifically improves near visual acuities but does not transfer to distance acuities or fine motor skills. Improvements in near visual acuity are retained over time, bolstering its clinical value.
Collapse
Affiliation(s)
- Bianca Huurneman
- Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Cognitive Neuroscience Department, Nijmegen, The Netherlands. .,Royal Dutch Visio, Nijmegen, The Netherlands.
| | - F Nienke Boonstra
- Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Cognitive Neuroscience Department, Nijmegen, The Netherlands.,Royal Dutch Visio, Nijmegen, The Netherlands
| | - Jeroen Goossens
- Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Cognitive Neuroscience Department, Nijmegen, The Netherlands
| |
Collapse
|
36
|
Donovan I, Shen A, Tortarolo C, Barbot A, Carrasco M. Exogenous attention facilitates perceptual learning in visual acuity to untrained stimulus locations and features. J Vis 2020; 20:18. [PMID: 32340029 PMCID: PMC7405812 DOI: 10.1167/jov.20.4.18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 01/08/2020] [Indexed: 12/11/2022] Open
Abstract
Visual perceptual learning (VPL) refers to the improvement in performance on a visual task due to practice. A hallmark of VPL is specificity, as improvements are often confined to the trained retinal locations or stimulus features. We have previously found that exogenous (involuntary, stimulus-driven) and endogenous (voluntary, goal-driven) spatial attention can facilitate the transfer of VPL across locations in orientation discrimination tasks mediated by contrast sensitivity. Here, we investigated whether exogenous spatial attention can facilitate such transfer in acuity tasks that have been associated with higher specificity. We trained observers for 3 days (days 2-4) in a Landolt acuity task (Experiment 1) or a Vernier hyperacuity task (Experiment 2), with either exogenous precues (attention group) or neutral precues (neutral group). Importantly, during pre-tests (day 1) and post-tests (day 5), all observers were tested with neutral precues; thus, groups differed only in their attentional allocation during training. For the Landolt acuity task, we found evidence of location transfer in both the neutral and attention groups, suggesting weak location specificity of VPL. For the Vernier hyperacuity task, we found evidence of location and feature specificity in the neutral group, and learning transfer in the attention group-similar improvement at trained and untrained locations and features. Our results reveal that, when there is specificity in a perceptual acuity task, exogenous spatial attention can overcome that specificity and facilitate learning transfer to both untrained locations and features simultaneously with the same training. Thus, in addition to improving performance, exogenous attention generalizes perceptual learning across locations and features.
Collapse
Affiliation(s)
- Ian Donovan
- Department of Psychology and Neural Science, New York University,New York,NY,USA
| | - Angela Shen
- Department of Psychology, New York University,New York,NY,USA
| | | | - Antoine Barbot
- Department of Psychology, New York University,New York,NY,USA
- Center for Neural Science, New York University,New York,NY,USA
| | - Marisa Carrasco
- Department of Psychology, New York University,New York,NY,USA
- Center for Neural Science, New York University,New York,NY,USA
| |
Collapse
|
37
|
Pedersini CA, Lingnau A, Cardobi N, Sanchez-Lopez J, Savazzi S, Marzi CA. Neural bases of visual processing of moving and stationary stimuli presented to the blind hemifield of hemianopic patients. Neuropsychologia 2020; 141:107430. [PMID: 32173624 DOI: 10.1016/j.neuropsychologia.2020.107430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 02/28/2020] [Accepted: 03/03/2020] [Indexed: 12/12/2022]
Abstract
Unilateral damage to post-chiasmatic visual pathways or cortical areas results in the loss of vision in the contralateral hemifield, known as hemianopia. Some patients, however, may retain the ability to perform an above chance unconscious detection or discrimination of visual stimuli presented to the blind hemifield, known as "blindsight". An important finding in blindsight research is that it can often be elicited by moving stimuli. Therefore, in the present study, we wanted to test whether moving stimuli might yield blindsight phenomena in patients with cortical lesions resulting in hemianopia, in a discrimination task where stimulus movement is orthogonal to the feature of interest. This could represent an important strategy for rehabilitation because it might improve discrimination ability of stimulus features different but related to movement, e.g. line orientation. We tested eight hemianopic patients and eight age-matched healthy controls in an orientation discrimination task with moving or static visual stimuli. During performance of the task we carried out fMRI scanning and tractography. Behaviourally, we did not find a reliable main effect of motion on orientation discrimination; however, an important result was that in different patients blindsight could occur only with moving or stationary stimuli or with both. As to brain imaging results, following presentation of moving stimuli to the blind hemifield, a widespread fronto-parietal bilateral network was recruited including areas of the dorsal stream and in particular bilateral motion area hMT + whose activation positively correlated with behavioural performance. This bilateral network was not activated in controls suggesting that it represents a compensatory functional change following brain damage. Moreover, there was a higher activation of ipsilesional area hMT+ in patients who performed above chance in the moving condition. By contrast, in patients who performed above chance in the static condition, we found a higher activation of contralesional area V1 and extrastriate visual areas. Finally, we found a linear relationship between structural integrity of the ipsilesional pathway connecting lateral geniculate nucleus (LGN) with motion area hMT+ and both behavioural performance and ipsilesional hMT + activation. These results support the role of LGN in modulating performance as well as BOLD amplitude in the absence of visual awareness in ipsilesional area hMT+ during an orientation discrimination task with moving stimuli.
Collapse
Affiliation(s)
- Caterina A Pedersini
- Physiology and Psychology Section, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Angelika Lingnau
- Faculty of Psychology, Education and Sport Science, Institute of Psychology, University of Regensburg, Germany; Centre for Mind/Brain Sciences (CIMeC), University of Trento, Trento, Italy
| | - Nicolò Cardobi
- Physiology and Psychology Section, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Javier Sanchez-Lopez
- Physiology and Psychology Section, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Silvia Savazzi
- Physiology and Psychology Section, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; Perception and Awareness (PandA) Laboratory, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; National Institute of Neuroscience, Verona, Italy
| | - Carlo A Marzi
- Physiology and Psychology Section, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; National Institute of Neuroscience, Verona, Italy
| |
Collapse
|
38
|
Shibuki K, Wakui I, Fujimura T, Tomikawa M, Hasegawa S. Rapid Recovery From Cortical Blindness Caused by an Old Cerebral Infarction. Front Neurol 2020; 11:69. [PMID: 32117028 PMCID: PMC7020609 DOI: 10.3389/fneur.2020.00069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/20/2020] [Indexed: 11/13/2022] Open
Abstract
When the primary visual cortex (V1) is damaged, cortical blindness results. However, visual information obtained from the superior colliculus (SC) or direct thalamic afferents to higher visual cortices produces unconscious visual functions called blindsight. Alarming visual stimuli suggesting the approach of a predator are known to trigger escape behaviors via visual information mediated by the SC and amygdala in small animals, and salient and dynamic visual stimuli also produce some conscious visual experience even in patients with blindsight. Fresh cortical blindness sometimes recovers spontaneously in patients with fresh cerebral damages, and recovery can be accelerated by early rehabilitation. However, the mechanisms underlying recovery are not well-known. We analyzed a patient with cortical blindness caused by an old cerebral infarction. After repeated presentation of alarming visual stimuli, the ability to detect visual stimuli in the impaired visual field showed behavioral short-term improvement (STI) within a few minutes. Repeated behavioral STI induction was followed by behavioral long-term improvement (LTI) lasting more than several days. After behavioral LTI, the patient partially recovered the ability to read letters presented in the impaired visual field. The behavioral STI experiment, which can be performed within 10 min, may serve as a clinical screening test for anticipating recovery from cortical blindness.
Collapse
Affiliation(s)
- Katsuei Shibuki
- Department of Clinical Laboratory, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan.,Brain Research Institute, Niigata University, Niigata, Japan
| | - Ichiro Wakui
- Department of Internal Medicine, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan
| | - Takeo Fujimura
- Department of Internal Medicine, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan
| | - Masaru Tomikawa
- Department of Neurosurgery, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan
| | - Shin Hasegawa
- Department of Internal Medicine, Kashiwazaki General Hospital and Medical Center, Kashiwazaki, Japan
| |
Collapse
|
39
|
Chokron S, Dubourg L, Garric C, Martinelli F, Perez C. Dissociations between perception and awareness in hemianopia. Restor Neurol Neurosci 2020; 38:189-201. [PMID: 31929128 DOI: 10.3233/rnn-190951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The most common visual defect to follow a lesion of the retrochiasmal pathways is homonymous hemianopia (HH), whereby patients are blind to the contralesional visual field of each eye. Homonymous hemianopia has been studied in terms of its deleterious consequences on perceptual, cognitive and motor tasks as well as because it represents an interesting model of vision loss after a unilateral lesion of the occipital lobe. From a behavioral perspective, in addition to exhibiting a severe deficit in their contralesional visual field, HH patients can also exhibit dissociations between perception and awareness. Firstly, HH patients suffering from anosognosia may be unaware of their visual field defect. Secondly, HH patients can present with unconscious visual abilities in the blind hemifield, a phenomenon referred to as blindsight. Thirdly, recent reports demonstrate that HH patients can suffer from a subtle deficit in their ipsilesional visual field that they are unaware of, a condition called sightblindness (i.e. the reverse case of 'blindsight'). Finally, HH patients may also exhibit visual hallucinations in their blind field; however, such patients are not systematically aware that their perceptions are unreal. In this review, we provide an overview of the visual-field losses in HH patients after a left or right unilateral occipital lesion. Furthermore, we explore the implications of these four phenomena for models of visual processing and rehabilitation of visual field defects in HH patients. Finally, in contrast to the traditional view that HH is solely a visual-field defect, we discuss why this deficit is an interesting model for studying the dissociation between perception and awareness.
Collapse
Affiliation(s)
- Sylvie Chokron
- Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Lucas Dubourg
- Institut de Neuropsychologie, Neurovision, NeuroCognition, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Clémentine Garric
- Laboratoire de Sciences Cognitives et Affectives, SCALab, CNRS UMR, Faculté de Médecine, Pôle Recherche et Université de Lille, Lille, France
| | - Fiora Martinelli
- Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Céline Perez
- Institut de Neuropsychologie, Neurovision, NeuroCognition, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| |
Collapse
|
40
|
Saionz EL, Melnick MD, Tadin D, Huxlin KR. Use it before you lose it: greater efficacy of visual training for recovering contrast sensitivity in subacute cortical blindness. J Vis 2019. [DOI: 10.1167/19.15.33] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Elizabeth L. Saionz
- Translational Biomedical Science Program, University of Rochester
- Medical Scientist Training Program, University of Rochester
- Flaum Eye Institute, University of Rochester
| | - Michael D. Melnick
- Dept. Brain and Cognitive Sciences, University of Rochester
- Flaum Eye Institute, University of Rochester
| | - Duje Tadin
- Dept. Brain and Cognitive Sciences, University of Rochester
- Flaum Eye Institute, University of Rochester
- Center for Visual Science; University of Rochester
| | - Krystel R. Huxlin
- Dept. Brain and Cognitive Sciences, University of Rochester
- Flaum Eye Institute, University of Rochester
- Center for Visual Science; University of Rochester
| |
Collapse
|
41
|
Choi MJ, Kim H, Nah HW, Kang DW. Digital Therapeutics: Emerging New Therapy for Neurologic Deficits after Stroke. J Stroke 2019; 21:242-258. [PMID: 31587534 PMCID: PMC6780014 DOI: 10.5853/jos.2019.01963] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 09/16/2019] [Indexed: 01/14/2023] Open
Abstract
Digital therapeutics is an evidence-based intervention using high-quality software, with the sole purpose of treatment. As many healthcare systems are encountering high demands of quality outcomes, the need for digital therapeutics is gradually increasing in the clinical field. We conducted review of the implications of digital therapeutics in the treatment of neurological deficits for stroke patients. The implications of digital therapeutics have been discussed in four domains: cognition, speech and aphasia, motor, and vision. It was evident that different forms of digital therapeutics such as online platforms, virtual reality trainings, and iPad applications have been investigated in many trials to test its feasibility in clinical use. Although digital therapeutics may deliver high-quality solutions to healthcare services, the medicalization of digital therapeutics is accompanied with many limitations. Clinically validated digital therapeutics should be developed to prove its efficacy in stroke rehabilitation.
Collapse
Affiliation(s)
- Mi Joo Choi
- School of Medical Sciences, University of Manchester, Manchester, UK
| | - Hana Kim
- Department of Neurology, University of Ulsan College of Medicine, Seoul, Korea
| | | | - Dong-Wha Kang
- Department of Neurology, University of Ulsan College of Medicine, Seoul, Korea.,Nunaps Inc., Seoul, Korea.,Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| |
Collapse
|
42
|
Boosting Learning Efficacy with Noninvasive Brain Stimulation in Intact and Brain-Damaged Humans. J Neurosci 2019; 39:5551-5561. [PMID: 31133558 DOI: 10.1523/jneurosci.3248-18.2019] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 04/10/2019] [Accepted: 05/08/2019] [Indexed: 12/11/2022] Open
Abstract
Numerous behavioral studies have shown that visual function can improve with training, although perceptual refinements generally require weeks to months of training to attain. This, along with questions about long-term retention of learning, limits practical and clinical applications of many such paradigms. Here, we show for the first time in female and male human participants that just 10 d of visual training coupled with transcranial random noise stimulation (tRNS) over visual areas causes dramatic improvements in visual motion perception. Relative to control conditions and anodal stimulation, tRNS-enhanced learning was at least twice as fast, and, crucially, it persisted for 6 months after the end of training and stimulation. Notably, tRNS also boosted learning in patients with chronic cortical blindness, leading to recovery of motion processing in the blind field after just 10 d of training, a period too short to elicit enhancements with training alone. In sum, our results reveal a remarkable enhancement of the capacity for long-lasting plastic and restorative changes when a neuromodulatory intervention is coupled with visual training.SIGNIFICANCE STATEMENT Our work demonstrates that visual training coupled with brain stimulation can dramatically reduce the training period from months to weeks, and lead to fast improvement in neurotypical subjects and chronic cortically blind patients, indicating the potential of our procedure to help restore damaged visual abilities for currently untreatable visual dysfunctions. Together, these results indicate the critical role of early visual areas in perceptual learning and reveal its capacity for long-lasting plastic changes promoted by neuromodulatory intervention.
Collapse
|
43
|
Larcombe SJ, Kulyomina Y, Antonova N, Ajina S, Stagg CJ, Clatworthy PL, Bridge H. Visual training in hemianopia alters neural activity in the absence of behavioural improvement: a pilot study. Ophthalmic Physiol Opt 2019; 38:538-549. [PMID: 30357899 PMCID: PMC6282990 DOI: 10.1111/opo.12584] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/08/2018] [Indexed: 01/01/2023]
Abstract
Background Damage to the primary visual cortex (V1) due to stroke often results in permanent loss of sight affecting one side of the visual field (homonymous hemianopia). Some rehabilitation approaches have shown improvement in visual performance in the blind region, but require a significant time investment. Methods Seven patients with cortical damage performed 400 trials of a motion direction discrimination task daily for 5 days. Three patients received anodal transcranial direct current stimulation (tDCS) during training, three received sham stimulation and one had no stimulation. Each patient had an assessment of visual performance and a functional magnetic resonance imaging (fMRI) scan before and after training to measure changes in visual performance and cortical activity. Results No patients showed improvement in visual function due to the training protocol, and application of tDCS had no effect on visual performance. However, following training, the neural response in motion area hMT+ to a moving stimulus was altered. When the stimulus was presented to the sighted hemifield, activity decreased in hMT+ of the damaged hemisphere. There was no change in hMT+ response when the stimulus was presented to the impaired hemifield. There was a decrease in activity in the inferior precuneus after training when the stimulus was presented to either the impaired or sighted hemifield. Preliminary analysis of tDCS data suggested that anodal tDCS interacted with the delivered training, modulating the neural response in hMT+ in the healthy side of the brain. Conclusion Training can affect the neural responses in hMT+ even in the absence of change in visual performance.
Collapse
Affiliation(s)
- Stephanie J Larcombe
- Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.,Nuffield Department of Clinical Neurosciences (NDCN), University of Oxford, Oxford, UK
| | - Yuliya Kulyomina
- Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.,Nuffield Department of Clinical Neurosciences (NDCN), University of Oxford, Oxford, UK
| | - Nikoleta Antonova
- Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Sara Ajina
- Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.,Nuffield Department of Clinical Neurosciences (NDCN), University of Oxford, Oxford, UK
| | - Charlotte J Stagg
- Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.,Nuffield Department of Clinical Neurosciences (NDCN), University of Oxford, Oxford, UK.,Department of Psychiatry, Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - Philip L Clatworthy
- Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Holly Bridge
- Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.,Nuffield Department of Clinical Neurosciences (NDCN), University of Oxford, Oxford, UK
| |
Collapse
|
44
|
Neuronal mechanisms of motion detection underlying blindsight assessed by functional magnetic resonance imaging (fMRI). Neuropsychologia 2019; 128:187-197. [PMID: 30825453 DOI: 10.1016/j.neuropsychologia.2019.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 12/27/2022]
Abstract
Brain imaging offers a valuable tool to observe functional brain plasticity by showing how sensory inputs reshape cortical activations after a visual impairment. Following a unilateral post-chiasmatic lesion affecting the visual cortex, patients may suffer a contralateral visual loss referred to homonymous hemianopia. Nevertheless, these patients preserve the ability to unconsciously detect, localize and discriminate visual stimuli presented in their impaired visual field. To investigate this paradox, known as blindsight, we conducted a study using functional magnetic resonance imaging (fMRI) to evaluate the structural and functional impact of such lesion in a 33-year old patient (ML), who suffers a complete right hemianopia without macular sparing and showing strong evidences of blindsight. We thus performed whole brain and sliced thalamic fMRI scan sequences during an event-related motion detection task. We provided evidence of the neuronal fingerprint of blindsight by acquiring and associating neural correlates, specific structures and functional networks of the midbrain during blindsight performances which may help to better understand this condition. Accurate performance demonstrated the presence of residual vision and the ability to unconsciously perceive motion presented in the blind hemifield, although her reaction time was significantly higher in her blind-field. When the normal hemifield was stimulated, we observed significant contralateral activations in primary and secondary visual areas as well as motion specific areas, such as the supramarginal gyrus and middle temporal area. We also demonstrated sub-thalamic activations within the superior colliculi (SC) and the pulvinar. These results suggest a role of secondary subcortical structures in normal spontaneous motion detection. In a similar way, when the lesioned hemifield was stimulated, we observed contralateral activity in extrastriate areas with no activation of the primary lesioned visual cortex. Moreover, we observed activations within the SC when the blind hemifield was stimulated. However, we observed unexpected ipsilateral activations within the same motion specific areas, as well as bilateral frontal activations. These results highlight the importance of abnormal secondary pathways bypassing the primary visual area (V1) in residual vision. This reorganization in the structure and function of the visual pathways correlates with behavioral changes, thus offering a plausible explanation for the blindsight phenomenon. Our results may potentially impact the development of rehabilitation strategies to target subcortical pathways.
Collapse
|
45
|
Rolfs M, Murray-Smith N, Carrasco M. Perceptual learning while preparing saccades. Vision Res 2018; 152:126-138. [PMID: 29277450 PMCID: PMC6028304 DOI: 10.1016/j.visres.2017.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/25/2017] [Accepted: 11/28/2017] [Indexed: 10/18/2022]
Abstract
Traditional perceptual learning protocols rely almost exclusively on long periods of uninterrupted fixation. Taking a first step towards understanding perceptual learning in natural vision, we had observers report the orientation of a briefly flashed stimulus (clockwise or counterclockwise from a reference orientation) presented strictly during saccade preparation at a location offset from the saccade target. For each observer, the saccade direction, stimulus location, and orientation remained the same throughout training. Subsequently, we assessed performance during fixation in three transfer sessions, either at the trained or at an untrained location, and either using an untrained (Experiment 1) or the trained (Experiment 2) stimulus orientation. We modeled the evolution of contrast thresholds (i.e., the stimulus contrast necessary to discriminate its orientation correctly 75% of the time) as an exponential learning curve, and quantified departures from this curve in transfer sessions using two new, complementary measures of transfer costs (i.e., performance decrements after the transition into the Transfer phase). We observed robust perceptual learning and associated transfer costs for untrained locations and orientations. We also assessed if spatial transfer costs were reduced for the remapped location of the pre-saccadic stimulus-the location the stimulus would have had (but never had) after the saccade. Although the pattern of results at that location differed somewhat from that at the control location, we found no clear evidence for perceptual learning at remapped locations. Using novel, model-based ways to assess learning and transfer costs, our results show that location and feature specificity, hallmarks of perceptual learning, subsist if the target stimulus is presented strictly during saccade preparation throughout training.
Collapse
Affiliation(s)
- Martin Rolfs
- Department of Psychology, New York University, NY, USA; Center for Neural Science, New York University, NY, USA; Department of Psychology, Humboldt-Universität zu Berlin, Germany; Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Germany.
| | | | - Marisa Carrasco
- Department of Psychology, New York University, NY, USA; Center for Neural Science, New York University, NY, USA
| |
Collapse
|
46
|
Donovan I, Carrasco M. Endogenous spatial attention during perceptual learning facilitates location transfer. J Vis 2018; 18:7. [PMID: 30347094 PMCID: PMC6181190 DOI: 10.1167/18.11.7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/02/2018] [Indexed: 11/24/2022] Open
Abstract
Covert attention and perceptual learning enhance perceptual performance. The relation between these two mechanisms is largely unknown. Previously, we showed that manipulating involuntary, exogenous spatial attention during training improved performance at trained and untrained locations, thus overcoming the typical location specificity. Notably, attention-induced transfer only occurred for high stimulus contrasts, at the upper asymptote of the psychometric function (i.e., via response gain). Here, we investigated whether and how voluntary, endogenous attention, the top-down and goal-based type of covert visual attention, influences perceptual learning. Twenty-six participants trained in an orientation discrimination task at two locations: half of participants received valid endogenous spatial precues (attention group), while the other half received neutral precues (neutral group). Before and after training, all participants were tested with neutral precues at two trained and two untrained locations. Within each session, stimulus contrast varied on a trial basis from very low (2%) to very high (64%). Performance was fit by a Weibull psychometric function separately for each day and location. Performance improved for both groups at the trained location, and unlike training with exogenous attention, at the threshold level (i.e., via contrast gain). The neutral group exhibited location specificity: Thresholds decreased at the trained locations, but not at the untrained locations. In contrast, participants in the attention group showed significant location transfer: Thresholds decreased to the same extent at both trained and untrained locations. These results indicate that, similar to exogenous spatial attention, endogenous spatial attention induces location transfer, but influences contrast gain instead of response gain.
Collapse
Affiliation(s)
- Ian Donovan
- Department of Psychology, New York University, New York, NY, USA
| | - Marisa Carrasco
- Department of Psychology and Center for Neural Science, New York University, New York, NY, USA
| |
Collapse
|
47
|
Psychophysical and neuroimaging responses to moving stimuli in a patient with the Riddoch phenomenon due to bilateral visual cortex lesions. Neuropsychologia 2018; 128:150-165. [PMID: 29753019 DOI: 10.1016/j.neuropsychologia.2018.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 05/07/2018] [Accepted: 05/07/2018] [Indexed: 01/31/2023]
Abstract
Patients with injury to early visual cortex or its inputs can display the Riddoch phenomenon: preserved awareness for moving but not stationary stimuli. We provide a detailed case report of a patient with the Riddoch phenomenon, MC. MC has extensive bilateral lesions to occipitotemporal cortex that include most early visual cortex and complete blindness in visual field perimetry testing with static targets. Nevertheless, she shows a remarkably robust preserved ability to perceive motion, enabling her to navigate through cluttered environments and perform actions like catching moving balls. Comparisons of MC's structural magnetic resonance imaging (MRI) data to a probabilistic atlas based on controls reveals that MC's lesions encompass the posterior, lateral, and ventral early visual cortex bilaterally (V1, V2, V3A/B, LO1/2, TO1/2, hV4 and VO1 in both hemispheres) as well as more extensive damage to right parietal (inferior parietal lobule) and left ventral occipitotemporal cortex (VO1, PHC1/2). She shows some sparing of anterior occipital cortex, which may account for her ability to see moving targets beyond ~15 degrees eccentricity during perimetry. Most strikingly, functional and structural MRI revealed robust and reliable spared functionality of the middle temporal motion complex (MT+) bilaterally. Moreover, consistent with her preserved ability to discriminate motion direction in psychophysical testing, MC also shows direction-selective adaptation in MT+. A variety of tests did not enable us to discern whether input to MT+ was driven by her spared anterior occipital cortex or subcortical inputs. Nevertheless, MC shows rich motion perception despite profoundly impaired static and form vision, combined with clear preservation of activation in MT+, thus supporting the role of MT+ in the Riddoch phenomenon.
Collapse
|
48
|
Seitz AR. A new framework of design and continuous evaluation to improve brain training. JOURNAL OF COGNITIVE ENHANCEMENT 2018; 2:78-87. [PMID: 29868648 PMCID: PMC5984043 DOI: 10.1007/s41465-017-0058-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Effective teaching critically relies upon effective evaluation because evaluation is required to gain understanding of existing abilities and, in turn, determine learning outcomes. Methods of effective evaluation are surprisingly elusive in many fields and this limits our understanding of which training methods are truly effective. In the present article, issues of effective evaluation are discussed in the context of "brain training," an exciting but much criticized field. Problems in test validity in the field of brain training, parallel those in many other fields; such as deficiencies in test reliability, teaching to the test, expectation effects, as well as statistical rigor. Here we review these issues and discuss how commonalities between the goals of evaluation and adaptive training procedures suggest a new paradigm that synthesizes evaluation and training. We suggest that continuous evaluation, where testing is integrated into the training, may provide a path towards greater reliability of skill evaluation, through longitudinal sampling, and validity, through better alignment of evaluation activities in respect to learning objectives.
Collapse
|
49
|
Elshout JA, Bergsma DP, Sibbel J, Baars-Elsinga A, Lubbers P, Van Asten F, Visser-Meily J, Van Den Berg AV. Improvement in activities of daily living after visual training in patients with homonymous visual field defects using Goal Attainment Scaling. Restor Neurol Neurosci 2018; 36:1-12. [DOI: 10.3233/rnn-170719] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Joris A. Elshout
- Department of Cognitive Neuroscience, Section of Biophysics, Donders Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Douwe P. Bergsma
- Department of Cognitive Neuroscience, Section of Biophysics, Donders Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Jacqueline Sibbel
- Department of Rehabilitation, Physical Therapy Science & Sports, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Annette Baars-Elsinga
- Department of Rehabilitation, Physical Therapy Science & Sports, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Paula Lubbers
- St. Maartenskliniek Rehabilitation, Nijmegen, The Netherlands
| | - Freekje Van Asten
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Johanna Visser-Meily
- Department of Rehabilitation, Physical Therapy Science & Sports, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Center of Excellence for Rehabilitation Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University and De Hoogstraat Rehabilitation, Utrecht, The Netherlands
| | - Albert V. Van Den Berg
- Department of Cognitive Neuroscience, Section of Biophysics, Donders Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| |
Collapse
|
50
|
Abstract
Much remains to be understood about visual system malfunction following injury. The resulting deficits range from dense, visual field scotomas to mild dysfunction of visual perception. Despite the predictive value of anatomical localization studies, much patient-to-patient variability remains regarding (a) perceptual abilities following injury and (b) the capacity of individual patients for visual rehabilitation. Visual field perimetry is used to characterize the visual field deficits that result from visual system injury. However, standard perimetry mapping does not always precisely correspond to underlying anatomical or functional deficits. Functional magnetic resonance imaging can be used to probe the function of surviving visual circuits, allowing us to classify better how the pattern of injury relates to residual visual perception. Identifying pathways that are potentially modifiable by training may guide the development of improved strategies for visual rehabilitation. This review discusses primary visual cortex lesions, which cause dense contralateral scotomas.
Collapse
Affiliation(s)
- Stelios M Smirnakis
- Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts 02115.,Department of Neurology, Jamaica Plain Campus, Veterans Administration Boston Healthcare System, Boston, Massachusetts 02130.,Harvard Medical School, Boston, Massachusetts 02115;
| |
Collapse
|