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Song F, Lyu L, Bao M. Adaptation of Ocular Opponency Neurons Mediates Attention-Induced Ocular Dominance Plasticity. Neurosci Bull 2024; 40:339-349. [PMID: 37635196 PMCID: PMC10912405 DOI: 10.1007/s12264-023-01103-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/01/2023] [Indexed: 08/29/2023] Open
Abstract
Previous research has shown that ocular dominance can be biased by prolonged attention to one eye. The ocular-opponency-neuron model of binocular rivalry has been proposed as a candidate account for this phenomenon. Yet direct neural evidence is still lacking. By manipulating the contrast of dichoptic testing gratings, here we measured the steady-state visually evoked potentials (SSVEPs) at the intermodulation frequencies to selectively track the activities of ocular-opponency-neurons before and after the "dichoptic-backward-movie" adaptation. One hour of adaptation caused a shift of perceptual and neural ocular dominance towards the unattended eye. More importantly, we found a decrease in the intermodulation SSVEP response after adaptation, which was significantly greater when high-contrast gratings were presented to the attended eye than when they were presented to the unattended eye. These results strongly support the view that the adaptation of ocular-opponency-neurons contributes to the ocular dominance plasticity induced by prolonged eye-based attention.
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Affiliation(s)
- Fangxing Song
- CAS Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, 100101, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lili Lyu
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
| | - Min Bao
- CAS Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, 100101, China.
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, 100049, China.
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Song T, Duan X. Ocular dominance in cataract surgery: research status and progress. Graefes Arch Clin Exp Ophthalmol 2024; 262:33-41. [PMID: 37644327 DOI: 10.1007/s00417-023-06216-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 08/17/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023] Open
Abstract
Ocular dominance (OD), a commonly used concept in clinical practice, plays an important role in optometry and refractive surgery. With the development of refractive cataract surgery, the refractive function of the intraocular lens determines the achievement of the postoperative full range of vision based on the retinal defocus blur suppression and binocular monovision principle. Therefore, OD plays an important role in cataract surgery. OD is related to the visual formation of the cerebral cortex, and its plasticity suggests that visual experience can influence the visual system. Cataract surgery changes the visual experience and transforms the dominant eye, which confirms the plasticity of the visual system. Based on the concept and mechanism of OD, this review summarizes the application of OD in cataract surgery.
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Affiliation(s)
- Tingting Song
- Jinan University, Guangzhou, China
- Changsha Aier Eye Hospital, Aier Eye Hospital Group, Tianxin District, 188 Furong South Road, Changsha, 410009, China
| | - Xuanchu Duan
- Jinan University, Guangzhou, China.
- Changsha Aier Eye Hospital, Aier Eye Hospital Group, Tianxin District, 188 Furong South Road, Changsha, 410009, China.
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Prosper A, Pasqualetti M, Morrone MC, Lunghi C. The duration effect of short-term monocular deprivation measured by binocular rivalry and binocular combination. Vision Res 2023; 211:108278. [PMID: 37352718 DOI: 10.1016/j.visres.2023.108278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/30/2023] [Accepted: 06/10/2023] [Indexed: 06/25/2023]
Abstract
The ocular dominance shift observed after short-term monocular deprivation is a widely used measure of visual homeostatic plasticity in adult humans. Binocular rivalry and binocular combination techniques are used interchangeably to characterize homeostatic plasticity, sometimes leading to contradictory results. Here we directly compare the effect of short-term monocular deprivation on ocular dominance measured by either binocular rivalry or binocular combination and its dependence on the duration of deprivation (15 or 120 min) in the same group of participants. Our results show that both binocular rivalry and binocular combination provide reliable estimates of ocular dominance, which are strongly correlated across techniques both before and after deprivation. Moreover, while 15 min of monocular deprivation induce a larger shift of ocular dominance when measured using binocular combination compared to binocular rivalry, for both techniques, the shift in ocular dominance exhibits a strong dependence on the duration of monocular deprivation, with longer deprivation inducing a larger and longer-lasting shift in ocular dominance. Taken together, our results indicate that both binocular rivalry and binocular combination offer very consistent and reliable measurements of both ocular dominance and the effect short-term monocular deprivation.
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Affiliation(s)
- Antoine Prosper
- Laboratoire Des Systèmes Perceptifs, Département d'études Cognitives, École Normale Supérieure, PSL University, CNRS, 75005 Paris, France
| | - Martina Pasqualetti
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Maria Concetta Morrone
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy; IRCCS Stella Maris Foundation, Pisa, Italy
| | - Claudia Lunghi
- Laboratoire Des Systèmes Perceptifs, Département d'études Cognitives, École Normale Supérieure, PSL University, CNRS, 75005 Paris, France.
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Meng Q, Wang L, Zhao M, Wu X, Guo L. Comparing myopic error in patients with basic and convergence insufficiency intermittent exotropia in China. BMC Ophthalmol 2023; 23:290. [PMID: 37365512 DOI: 10.1186/s12886-023-03043-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/14/2023] [Indexed: 06/28/2023] Open
Abstract
PURPOSE To compare the degree of myopia between the dominant and non-dominant eyes in teenagers with intermittent exotropia (IXT) in China. METHODS A total of 199 IXT patients with myopia were included in this retrospective study and were divided into two groups according to the difference between near and distance exodeviation: basic IXT and convergence insufficiency (CI) IXT. Refractive errors were analyzed by spherical equivalent (SE) values. Patients were further stratified into anisometropia group and non-anisometropia group based on binocular SE values difference greater than 1.0D or not. RESULTS There were 127 patients in the CI IXT group, with a near deviation of 46.94 ± 20.53 prism diopters (PD) and a distance deviation of 28.36 ± 14.34 PD, and there were 72 (36.2%) patients in the basic IXT group, with a near deviation of 37.68 ± 22.21 PD and a distance deviation angle of 33.21 ± 23.96 PD. The near exodeviation was significantly larger in the CI group than in the basic IXT group(P < 0.001). In the CI IXT group, the mean SE was - 2.09 ± 1.45 diopters (D) in the dominant eye and - 2.53 ± 1.44D in the non-dominant eye, while in the basic IXT group, the mean SE was - 2.46 ± 1.56D in the dominant eye and - 2.89 ± 1.37D in the non-dominant eye. The anisometropia group included 43 patients, while non-anisometropia group included 156 patients. The near and distance exodeviation in the anisometropia group were 45.26 ± 24.41 PD and 33.53 ± 23.31 PD, respectively, and those in the non-anisometropia group were 43.42 ± 20.69 PD and 29.07 ± 16.84 PD, respectively. There were no significant differences in near and distance deviation (P = 0.78 and P = 0.73 respectively) between the two groups. The SE of the dominant eye was less myopic than of the non-dominant eyes in both the CI and anisometropia groups (P = 0.002 and P < 0.001, respectively). CONCLUSIONS Our study revealed that convergence insufficiency IXT is more common than the basic type in pediatric myopic population and is characterized by higher inter-eye differences of myopia. The dominant eye was found to be less myopic in IXT patients, particularly in those with convergence insufficiency and anisometropia.
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Affiliation(s)
- Qingyu Meng
- Department of Ophthalmology & Clinical Centre of Optometry, Peking University People's Hospital, Beijing, China
- Eye Disease and Optometry Institute, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Lejin Wang
- Department of Ophthalmology & Clinical Centre of Optometry, Peking University People's Hospital, Beijing, China
- Eye Disease and Optometry Institute, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Mingwei Zhao
- Department of Ophthalmology & Clinical Centre of Optometry, Peking University People's Hospital, Beijing, China
- Eye Disease and Optometry Institute, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Xi Wu
- Department of Ophthalmology & Clinical Centre of Optometry, Peking University People's Hospital, Beijing, China
- Eye Disease and Optometry Institute, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Lili Guo
- Department of Ophthalmology & Clinical Centre of Optometry, Peking University People's Hospital, Beijing, China.
- Eye Disease and Optometry Institute, Peking University People's Hospital, Beijing, China.
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
- College of Optometry, Peking University Health Science Center, Beijing, China.
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Li VJ, Chorghay Z, Ruthazer ES. A Guide for the Multiplexed: The Development of Visual Feature Maps in the Brain. Neuroscience 2023; 508:62-75. [PMID: 35952996 DOI: 10.1016/j.neuroscience.2022.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 01/17/2023]
Abstract
Neural maps are found ubiquitously in the brain, where they encode a wide range of behaviourally relevant features into neural space. Developmental studies have shown that animals devote a great deal of resources to establish consistently patterned organization in neural circuits throughout the nervous system, but what purposes maps serve beneath their often intricate appearance and composition is a topic of active debate and exploration. In this article, we review the general mechanisms of map formation, with a focus on the visual system, and then survey notable organizational properties of neural maps: the multiplexing of feature representations through a nested architecture, the interspersing of fine-scale heterogeneity within a globally smooth organization, and the complex integration at the microcircuit level that enables a high dimensionality of information encoding. Finally, we discuss the roles of maps in cortical functions, including input segregation, feature extraction and routing of circuit outputs for higher order processing, as well as the evolutionary basis for the properties we observe in neural maps.
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Affiliation(s)
- Vanessa J Li
- Montreal Neurological Institute-Hospital, McGill University, 3801 University St. Montreal, Quebec H3A 2B4, Canada
| | - Zahraa Chorghay
- Montreal Neurological Institute-Hospital, McGill University, 3801 University St. Montreal, Quebec H3A 2B4, Canada
| | - Edward S Ruthazer
- Montreal Neurological Institute-Hospital, McGill University, 3801 University St. Montreal, Quebec H3A 2B4, Canada
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Baldwin AS, Finn AE, Green HM, Gant N, Hess RF. Exercise does not enhance short-term deprivation-induced ocular dominance plasticity: evidence from dichoptic surround suppression. Vision Res 2022; 201:108123. [PMID: 36193605 DOI: 10.1016/j.visres.2022.108123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/09/2022] [Accepted: 09/05/2022] [Indexed: 11/06/2022]
Abstract
The input from the two eyes is combined in the brain. In this combination, the relative strength of the input from each eye is determined by the ocular dominance. Recent work has shown that this dominance can be temporarily shifted. Covering one eye with an eye patch for a few hours makes its contribution stronger. It has been proposed that this shift can be enhanced by exercise. Here, we test this hypothesis using a dichoptic surround suppression task, and with exercise performed according to American College of Sport Medicine guidelines. We measured detection thresholds for patches of sinusoidal grating shown to one eye. When an annular mask grating was shown simultaneously to the other eye, thresholds were elevated. The difference in the elevation found in each eye is our measure of relative eye dominance. We made these measurements before and after 120 min of monocular deprivation (with an eye patch). In the control condition, subjects rested during this time. For the exercise condition, 30 min of exercise were performed at the beginning of the patching period. This was followed by 90 min of rest. We find that patching results in a shift in ocular dominance that can be measured using dichoptic surround suppression. However, we find no effect of exercise on the magnitude of this shift. We further performed a meta-analysis on the four studies that have examined the effects of exercise on the dominance shift. Looking across these studies, we find no evidence for such an effect.
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Tuna AR, Pinto N, Fernandes A, Brardo FM, Pato MV. Theta burst stimulation in adults with symmetric and asymmetric visual acuity. Int Ophthalmol 2022; 42:2785-2799. [PMID: 35353292 DOI: 10.1007/s10792-022-02269-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 03/12/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE Theta Burst Stimulation can influence adult neuro-visual response in imbalanced visual pathways, possibly by influencing cortical excitability. Our objective was to compare suppressive imbalance (SI) and visual acuity (VA) after applying repetitive Transcranial Magnetic Stimulation between groups of subjects with normal binocular vision, visual asymmetry, and amblyopia. METHODS Thirty-five volunteers between 19 and 51 years of age were split into three groups: 6 volunteers with asymmetric VA (group A); 19 amblyopes (group B); and 10 subjects with normal binocular vision (group C). VA and SI of all groups were evaluated before and after a single session of continuous Theta Burst Stimulation (cTBS) or placebo stimulation over the right occipital cortex. RESULTS In both groups A and B, we found a significant VA improvement in the non-dominant eye after cTBS (p = 0.04 and p = 0.01, respectively). In SI evaluation, group A and group B also revealed a significant improvement after the cTBS session (p = 0.03 and p = 0.01, respectively). Finally, in the group of volunteers with normal binocular vision and for placebo groups A and B, there were no significant differences in VA and SI after cTBS. CONCLUSIONS Amblyopic and visually asymmetric individuals improved VA and SI of the non-dominant eye after cTBS when compared to baseline and to placebo stimulation. These enhancements were not found in the group of volunteers with normal binocular vision. We can therefore reasonably assume that cTBS may interfere with the visual system of subjects that present some kind of asymmetry, possibly by improving neuronal imbalances.
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Affiliation(s)
- Ana Rita Tuna
- Faculty of Health Sciences, CICS-Health Sciences Research Centre, University of Beira Interior, Rua Marquês D'Ávila e Bolama, 6201-001, Covilhã, Portugal.
| | - Nuno Pinto
- Faculty of Health Sciences, CICS-Health Sciences Research Centre, University of Beira Interior, Rua Marquês D'Ávila e Bolama, 6201-001, Covilhã, Portugal
| | - Andresa Fernandes
- Faculty of Health Sciences, CICS-Health Sciences Research Centre, University of Beira Interior, Rua Marquês D'Ávila e Bolama, 6201-001, Covilhã, Portugal
| | - Francisco Miguel Brardo
- Faculty of Health Sciences, CICS-Health Sciences Research Centre, University of Beira Interior, Rua Marquês D'Ávila e Bolama, 6201-001, Covilhã, Portugal.,Department of Physics, University of Beira Interior, Covilhã, Portugal
| | - Maria Vaz Pato
- Faculty of Health Sciences, CICS-Health Sciences Research Centre, University of Beira Interior, Rua Marquês D'Ávila e Bolama, 6201-001, Covilhã, Portugal
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8
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Choi MY, Choi JA. Ocular Dominance in Open Angle Glaucoma: the shifting trend depending on stage of the disease. Korean J Ophthalmol 2022; 36:236-243. [PMID: 35176838 PMCID: PMC9194727 DOI: 10.3341/kjo.2021.0165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/10/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose To investigate the characteristics and distribution of ocular dominance in primary open-angle glaucoma eyes. In addition, we tried to catch any trend of ocular dominance according to the stage of disease. Methods Two hundred participants with bilateral open-angle glaucoma underwent ocular dominant testing by “the hole-in-a-card” test. Using optical coherence tomography, macular ganglion cell-inner plexiform layer, as well as circumpapillary retinal nerve fiber layer thickness were measured and compared according to ocular dominance. Of the two eyes of one subject, the eye with less glaucomatous damage based on mean deviation was considered to be the “better eye” in our study. Results Ocular dominance was in the right eye in 66% of the population and ocular dominance was positioned in the better eye in 70% of the population (p = 0.001 and p = 0.002, respectively). In conditional logistic regression analyses, right eye and better mean deviation were significantly associated with ocular dominance (p = 0.001 and p = 0.002, respectively). Ocular dominance tends to be present in the better eye and this trend was more apparent as the severity of glaucoma increased. Intereye comparison of visual field indices and retinal nerve fiber layer thickness between dominant versus nondominant eye become apparent in moderate and advanced glaucoma whereas it was not as apparent in early glaucoma. Conclusions In glaucomatous eyes, laterality and severity of glaucoma determined ocular dominance. Intereye difference between nondominant and dominant eyes increased with the severity of glaucoma. Our findings suggest the existence of potential reciprocal interactions between ocular dominance and glaucoma.
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Affiliation(s)
- Moon Young Choi
- Department of Ophthalmology and Visual Science, St. Vincent's Hospital, College of Medicine, the Catholic University of Korea, Seoul, Korea
| | - Jin A Choi
- Department of Ophthalmology and Visual Science, St. Vincent's Hospital, College of Medicine, the Catholic University of Korea, Seoul, Korea
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Nguyen BN, Malavita M, Carter OL, McKendrick AM. Neuroplasticity in older adults revealed by temporary occlusion of one eye. Cortex 2021; 143:1-11. [PMID: 34365199 DOI: 10.1016/j.cortex.2021.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 06/23/2021] [Accepted: 07/01/2021] [Indexed: 12/01/2022]
Abstract
Occluding one eye for several hours alters visual experience. Specifically, occluding one eye shifts the balance of ocular dominance to favour the recently deprived eye, which can be measured using binocular rivalry. This ocular dominance shift demonstrates homeostatic neuroplasticity within the visual system and has been explored in detail in younger adults. Here we measure whether the strength and general features of neuroplasticity revealed by monocular patching are maintained in older adults. Thirty younger (18-35 years) and 30 older adults (60-81 years) participated. Binocular rivalry features were measured before and after 2 h of occlusion. Post-patching, perceptual dominance of the non-patched eye decreased (p < .001) in both age groups. The effect of occlusion on all features of binocular rivalry did not significantly differ between groups. The older visual system maintains the ability to rapidly adjust to changes in perceptual experience induced by eye occlusion. This preservation of neuroplasticity suggests that visual training methods designed to improve visual performance based on eye occlusion should maintain effectiveness into older age.
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Affiliation(s)
- Bao N Nguyen
- C/O Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Menaka Malavita
- C/O Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Olivia L Carter
- C/O School of Psychological Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Allison M McKendrick
- C/O Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia.
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Georgeson MA, Sengpiel F. Contrast adaptation and interocular transfer in cortical cells: A re-analysis & a two-stage gain-control model of binocular combination. Vision Res 2021; 185:29-49. [PMID: 33894463 DOI: 10.1016/j.visres.2021.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 01/17/2021] [Accepted: 03/09/2021] [Indexed: 11/28/2022]
Abstract
How do V1 cells respond to, adapt to, and combine signals from the two eyes? We tested a simple functional model that has monocular and binocular stages of divisive contrast gain control (CGC) that sit before, and after, binocular summation respectively. Interocular suppression (IOS) was another potential influence on contrast gain. Howarth, Vorobyov & Sengpiel (2009, Cerebral Cortex, 19, 1835-1843) studied contrast adaptation and interocular transfer in cat V1 cells. In our re-analysis we found that ocular dominance (OD) and contrast adaptation at a fixed test contrast were well described by a re-scaling of the unadapted orientation tuning curve - a simple change in response gain. We compared six variants of the basic model, and one model fitted the gain data notably better than the others did. When the dominant eye was tested, adaptation reduced cell response gain more when that eye was adapted than when the other eye was adapted. But when the non-dominant eye was tested, adapting either eye gave about the same reduction in overall gain, and there was an interaction between OD and adapting eye that was well described by the best-fitting model. Two key features of this model are that signals driving IOS arise 'early', before attenuation due to OD, while suppressive CGC signals are 'late' and so affected by OD. We show that late CGC confers a functional advantage: it yields partial compensation for OD, which should reduce ocular imbalance at the input to binocular summation, and improve the cell's sensitivity to variation in stereo disparity.
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Affiliation(s)
- Mark A Georgeson
- College of Health & Life Sciences, Aston University, B4 7ET, UK.
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Matsuda YT, Miyamoto H, Joho RH, Hensch TK. K v3.1 channels regulate the rate of critical period plasticity. Neurosci Res 2021; 167:3-10. [PMID: 33872635 DOI: 10.1016/j.neures.2021.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/18/2022]
Abstract
Experience-dependent plasticity within visual cortex is controlled by postnatal maturation of inhibitory circuits, which are both morphologically diverse and precisely connected. Gene-targeted disruption of the voltage-dependent potassium channel Kv3.1 broadens action potentials and reduces net inhibitory function of parvalbumin (PV)-positive GABA subtypes within the neocortex. In mice lacking Kv3.1, the rate of input loss from an eye deprived of vision was slowed two-fold, despite otherwise normal critical period timecourse and receptive field properties. Rapid ocular dominance plasticity was restored by local or systemic enhancement of GABAergic transmission with acute benzodiazepine infusion. Diazepam instead exacerbated a global suppression of slow-wave oscillations during sleep described previously in these mutant mice, which therefore did not account for the rescued plasticity. Rapid ocular dominance shifts closely reflected Kv3.1 gene dosage that prevented prolonged spike discharge of their target pyramidal cells in vivo or the spike amplitude decrement of fast-spiking cells during bouts of high-frequency firing in vitro. Late postnatal expression of this unique channel in fast-spiking interneurons thus subtly regulates the speed of critical period plasticity with implications for mental illnesses.
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Affiliation(s)
- Yoshi-Taka Matsuda
- Laboratory for Neuronal Circuit Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan; Department of Child Studies, Shiraume Gakuen University, 1-830 Kodaira-shi, Tokyo, 187-8570 Japan
| | - Hiroyuki Miyamoto
- Laboratory for Neuronal Circuit Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan; International Research Center for Neurointelligence, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Rolf H Joho
- Center for Basic Neuroscience, Univ. Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Takao K Hensch
- Laboratory for Neuronal Circuit Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan; International Research Center for Neurointelligence, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan; Center for Brain Science, Department of Molecular Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA.
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12
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Moon Y, Kim JH, Lim HT. Difference in myopia progression between dominant and non-dominant eye in patients with intermittent exotropia. Graefes Arch Clin Exp Ophthalmol 2020; 258:1327-1333. [PMID: 32307585 DOI: 10.1007/s00417-020-04700-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/07/2020] [Accepted: 04/09/2020] [Indexed: 10/24/2022] Open
Abstract
OBJECTIVE To investigate the difference in the rate of myopia progression between the dominant and non-dominant eye in patients with intermittent exotropia (IXT). METHODS We retrospectively reviewed the medical records of 33 patients who underwent surgery and later reoperation for IXT. We included only patients whose spherical equivalent refractive errors (SER) were ≤ - 0.50 diopter (D) in at least one eye at the time of reoperation. The main outcome measurement was the rate of myopia progression, which was defined as the mean annual change in SER between the first and second surgery. We classified patients into two groups: group A, which comprised 25 patients whose non-dominant eyes showed a faster myopia progression than their dominant eyes, and group B, which comprised the remaining 8 patients showing the opposite. RESULTS Mean age of the patients at the time of the initial surgery was 5.64 years. Mean interval between the initial and second surgery was 4.45 years. Mean rate of myopia progression over the interval was - 0.37 D/year in the dominant eyes and - 0.50 D/year in the non-dominant eyes (P < 0.001). Group A had a significantly greater amount of distance deviation (31.0 vs. 25.6 PD, P = 0.020) and near deviation (30.8 vs 26.0 PD, P = 0.039) before the initial surgery and a significantly worse score of distance control (3.05 vs. 2.00, P = 0.023) before the second surgery than group B. CONCLUSIONS The non-dominant eyes experienced a faster myopia progression than the dominant eyes in patients with IXT. This faster myopia progression demonstrated in the non-dominant eyes was associated with clinically severe exotropia in terms of the amount of deviation and the degree of control.
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Affiliation(s)
- Yeji Moon
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-Ro 43 Gil, Songpa-gu, Seoul, 05505, South Korea
| | - Jin Hyun Kim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-Ro 43 Gil, Songpa-gu, Seoul, 05505, South Korea
| | - Hyun Taek Lim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-Ro 43 Gil, Songpa-gu, Seoul, 05505, South Korea.
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Zarei-Ghanavati S, Eslampour A, Shokouhirad S, Mazloum J, Yousefian A, Hassanzadeh S, Bakhtiari E, Eghbali P. The effect of eye dominancy on patients' cooperation and perceived pain during photorefractive keratectomy. J Curr Ophthalmol 2019; 31:373-376. [PMID: 31844785 PMCID: PMC6896458 DOI: 10.1016/j.joco.2019.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/19/2019] [Accepted: 07/03/2019] [Indexed: 11/26/2022] Open
Abstract
Purpose To find a possible association between patients' cooperation, perceived pain, and ocular dominance in patients who undergo photorefractive keratectomy (PRK). Methods One hundred-one eligible candidates for PRK refractive surgery were recruited. Preoperative exams were performed for all patients, and the dominant eye was specified. The surgeon was unaware about which eye was dominant. After surgery, the surgeon completed a cooperation score form for each patient. Ocular cyclotorsion, cooperation, and perceived pain scores were compared between the first-second eye surgeries and between dominant-non-dominant eyes surgeries. Results The dominant eye was the right eye in 68 patients and the left eye in 33 patients. First, eye surgery was performed on the dominant eye in 56 patients and on the non-dominant eye in 45 patients. Cooperation score and perceived pain were not significantly different between the first and second eye surgeries (P = 0.902 and P = 0.223, respectively), but cyclotorsion was more in the second eye (P = 0.031). Cooperation score, pain score, and cyclotorsion were not significantly different between dominant and non-dominant eye surgeries (P = 0.538, P = 0.581, and P = 0.193, respectively). Also, there was no correlation between cooperation score and duration of the surgery for the first or second eye (P = 0.12 and P = 0.78). Conclusion During PRK surgery, the patients' cooperation and perceived pain did not seem to be associated with eye laterality or dominancy.
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Affiliation(s)
| | - Alireza Eslampour
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saeed Shokouhirad
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Javad Mazloum
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Yousefian
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Samira Hassanzadeh
- Student Research Committee, Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Elham Bakhtiari
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Pardis Eghbali
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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Paschke K, Bähr M, Wüstenberg T, Wilke M. Trunk rotation and handedness modulate cortical activation in neglect-associated regions during temporal order judgments. Neuroimage Clin 2019; 23:101898. [PMID: 31491819 PMCID: PMC6627032 DOI: 10.1016/j.nicl.2019.101898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 05/13/2019] [Accepted: 06/13/2019] [Indexed: 12/02/2022]
Abstract
The rotation of the trunk around its vertical midline could be shown to bias visuospatial temporal judgments towards targets in the hemifield ipsilateral to the trunk orientation and to improve visuospatial performance in patients with visual neglect. However, the underlying brain mechanisms are not well understood. Therefore, the goal of the present study was to investigate the neural effects associated with egocentric midplane shifts under consideration of individual handedness. We employed a visuospatial temporal order judgment (TOJ) task in healthy right- and left-handed subjects while their trunk rotation was varied. Participants responded by a saccade towards the stimulus perceived first out of two stimuli presented with different stimulus onset asynchronies (SOA). Apart from gaze behavior, BOLD-fMRI responses were measured using functional magnetic resonance imaging (fMRI). Based on findings from spatial neglect research, analyses of fMRI-BOLD responses were focused on a bilateral fronto-temporo-parietal network comprising Brodmann areas 22, 39, 40, and 44, as well as the basal ganglia core nuclei (caudate, putamen, pallidum). We observed an acceleration of saccadic speed towards stimuli ipsilateral to the trunk orientation modulated by individual handedness. Left-handed participants showed the strongest behavioral and neural effects, suggesting greater susceptibility to manipulations of trunk orientation. With respect to the dominant hand, a rotation around the vertical trunk midline modulated the activation of an ipsilateral network comprising fronto-temporo-parietal regions and the putamen with the strongest effects for saccades towards the hemifield opposite to the dominant hand. Within the investigated network, the temporo-parietal junction (TPJ) appears to serve as a region integrating sensory, motor, and trunk position information. Our results are discussed in the context of gain modulatory and laterality effects. We examined the effect of trunk rotation on brain responses in neglect-associated areas.Trunk-related BOLD-fMRI activation patterns depend on handedness. They were modulated most during trunk rotation contralateral to the dominant hand. Trunk rotation and saccade direction show interaction effects at TPJ. TPJ serves as a region integrating sensory, motor, and trunk position information.
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Affiliation(s)
- Kerstin Paschke
- Department of Cognitive Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany; German Center for Addiction Research in Childhood and Adolescence, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg 20246, Germany; Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, Goettingen 37075, Germany.
| | - Mathias Bähr
- Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, Goettingen 37075, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Germany
| | - Torsten Wüstenberg
- Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Berlin Institute of Health, Humboldt-Universität zu Berlin, Charité Campus Mitte, Charitéplatz 1, Berlin 10117, Germany; Systems Neuroscience in Psychiatry (SNiP), Central Institute of Mental Health, Mannheim, J5, Mannheim 68159, Germany
| | - Melanie Wilke
- Department of Cognitive Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Germany; German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, Göttingen 37077, Germany; Leibniz-science campus primate cognition, Germany
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15
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Kemper VG, De Martino F, Emmerling TC, Yacoub E, Goebel R. High resolution data analysis strategies for mesoscale human functional MRI at 7 and 9.4T. Neuroimage 2018; 164:48-58. [PMID: 28416453 DOI: 10.1016/j.neuroimage.2017.03.058] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/22/2017] [Accepted: 03/28/2017] [Indexed: 01/22/2023] Open
Abstract
The advent of ultra-high field functional magnetic resonance imaging (fMRI) has greatly facilitated submillimeter resolution acquisitions (voxel volume below (1 mm³)), allowing the investigation of cortical columns and cortical depth dependent (i.e. laminar) structures in the human brain. Advanced data analysis techniques are essential to exploit the information in high resolution functional measures. In this article, we use recent, exemplary 9.4 T human functional and anatomical data to review the advantages and disadvantages of (1) pooling high resolution data across regions of interest for cortical depth profile analysis, (2) pooling across cortical depths for mapping patches of cortex while discarding depth-dependent (i.e. columnar) effects, and (3) isotropic sampling without pooling to assess individual voxel’s responses. A set of cortical depth meshes may be a solution to sampling information tangentially while keeping correspondence across depths. For quantitative analysis of the spatial organization in fine-grained structures, a cortical grid approach is advantageous. We further extend this general framework by combining it with a previously introduced cortical layer volume-preserving (equi-volume) approach. This framework can readily accommodate the research questions which allow for spatial smoothing within or across layers. We demonstrate and discuss that equi-volume sampling yields a slight advantage over equidistant sampling given the current limitations of fMRI voxel size, participant motion, coregistration and segmentation. Our 9.4 T human anatomical and functional data indicate the advantage over lower fields including 7 T and demonstrate the practical applicability of T2* and T2-weighted fMRI acquisitions. High resolution regular cortical grids are advantageous for local applications. Equi-volume sampling is slightly advantageous over equidistant sampling in-vivo. Isotropic submillimeter cortical sampling without spatial pooling requires high SNR. 9.4 T human T2 and T2* BOLD fMRI are practically feasible and provide high SNR. 9.4 T T2*-weighted 0.35 mm iso. res. anatomical images for laminar contrast in vivo.
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Paschke K, Kagan I, Wüstenberg T, Bähr M, Wilke M. Trunk rotation affects temporal order judgments with direct saccades: Influence of handedness. Neuropsychologia 2015; 79:123-37. [PMID: 26518506 DOI: 10.1016/j.neuropsychologia.2015.10.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/21/2015] [Accepted: 10/25/2015] [Indexed: 10/22/2022]
Abstract
Manipulation of the trunk midline has been shown to improve visuospatial performance in patients with unilateral visual neglect. The goal of the present study was to disentangle motor and perceptual components of egocentric midline manipulations and to investigate the contribution of individual hand preference. Two versions of visual temporal order judgment (TOJ) tasks were tested in healthy right- and left-handed subjects while trunk rotation was varied. In the congruent version, subjects were required to execute a saccade to the first of two horizontal stimuli presented with different stimulus onset asynchronies (SOA). In the incongruent version, subjects were required to perform a vertical saccade to a pre-learned color target, thereby dissociating motor response from the perceptual stimulus location. The main findings of this study are a trunk rotation and response direction specific impact on temporal judgments in form of a prior entry bias for right hemifield stimuli during rightward trunk rotation, but only in the congruent task. This trunk rotation-induced spatial bias was most pronounced in left-handed participants but had the same sign in the right-handed group. Results suggest that egocentric midline shifts in healthy subjects induce a spatially-specific motor, but not a perceptual, bias and underline the importance of taking individual differences in functional laterality such as handedness and mode of perceptual report into account when evaluating effects of trunk rotation in either healthy subjects or neurological patients.
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Affiliation(s)
- Kerstin Paschke
- Department of Cognitive Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; Department of Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany; Department of Child and Adolescent Psychiatry, University Medicine Goettingen, von-Siebold-Str. 5, 37075 Goettingen, Germany
| | - Igor Kagan
- Department of Cognitive Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Goettingen, Germany
| | - Torsten Wüstenberg
- Department of Psychiatry and Psychotherapy, Charité-University Medicine Berlin, Campus Mitte, Charitéplatz 1, 10117 Berlin, Germany
| | - Mathias Bähr
- Department of Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Germany
| | - Melanie Wilke
- Department of Cognitive Neurology, University Medicine Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany; German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Goettingen, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Germany.
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17
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Shooner C, Hallum LE, Kumbhani RD, Ziemba CM, Garcia-Marin V, Kelly JG, Majaj NJ, Movshon JA, Kiorpes L. Population representation of visual information in areas V1 and V2 of amblyopic macaques. Vision Res 2015; 114:56-67. [PMID: 25637856 DOI: 10.1016/j.visres.2015.01.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/15/2015] [Accepted: 01/18/2015] [Indexed: 10/24/2022]
Abstract
Amblyopia is a developmental disorder resulting in poor vision in one eye. The mechanism by which input to the affected eye is prevented from reaching the level of awareness remains poorly understood. We recorded simultaneously from large populations of neurons in the supragranular layers of areas V1 and V2 in 6 macaques that were made amblyopic by rearing with artificial strabismus or anisometropia, and 1 normally reared control. In agreement with previous reports, we found that cortical neuronal signals driven through the amblyopic eyes were reduced, and that cortical neurons were on average more strongly driven by the non-amblyopic than by the amblyopic eyes. We analyzed multiunit recordings using standard population decoding methods, and found that visual signals from the amblyopic eye, while weakened, were not degraded enough to explain the behavioral deficits. Thus additional losses must arise in downstream processing. We tested the idea that under monocular viewing conditions, only signals from neurons dominated by - rather than driven by - the open eye might be used. This reduces the proportion of neuronal signals available from the amblyopic eye, and amplifies the interocular difference observed at the level of single neurons. We conclude that amblyopia might arise in part from degradation in the neuronal signals from the amblyopic eye, and in part from a reduction in the number of signals processed by downstream areas.
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Affiliation(s)
- Christopher Shooner
- Center for Neural Science, New York University, New York, NY 10003, United States
| | - Luke E Hallum
- Center for Neural Science, New York University, New York, NY 10003, United States
| | - Romesh D Kumbhani
- Center for Neural Science, New York University, New York, NY 10003, United States
| | - Corey M Ziemba
- Center for Neural Science, New York University, New York, NY 10003, United States
| | | | - Jenna G Kelly
- Center for Neural Science, New York University, New York, NY 10003, United States
| | - Najib J Majaj
- Center for Neural Science, New York University, New York, NY 10003, United States
| | - J Anthony Movshon
- Center for Neural Science, New York University, New York, NY 10003, United States
| | - Lynne Kiorpes
- Center for Neural Science, New York University, New York, NY 10003, United States.
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Soroker N, Cohen T, Baratz C, Glicksohn J, Myslobodsky MS. Is there a place for ipsilesional eye patching in neglect rehabilitation? Behav Neurol 2014; 7:159-64. [PMID: 24487330 DOI: 10.3233/ben-1994-73-408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Neglect behavior of experimental animals with unilateral posterior cortical lesions improves with the placement of a second lesion in the contralesional superior colliculus or in the intercollicular commissure. Given that the retinotectal fibers are mainly crossed, it has been speculated that ipsilesional eye patching, by depriving the contralesional superior colliculus of its main facilitatory visual input, might achieve similar results, and thus be used as a remediation maneuver in patients with neglect. From six patients with severe persistent neglect, only one showed an unequivocal beneficial effect from ipsilesional eye patching. We discuss the factors which possibly underlie success and failure with this procedure, and the place for it in neglect rehabilitation.
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Affiliation(s)
- N Soroker
- Loewenstein Rehabilitation Hospital, Raanana, and the Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - T Cohen
- The Psychobiology Research Unit, Tel-Aviv University, Tel-Aviv, Israel
| | - C Baratz
- The Psychobiology Research Unit, Tel-Aviv University, Tel-Aviv, Israel
| | - J Glicksohn
- The Psychobiology Research Unit, Tel-Aviv University, Tel-Aviv, Israel
| | - M S Myslobodsky
- The Psychobiology Research Unit, Tel-Aviv University, Tel-Aviv, Israel
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19
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Pribiag H, Stellwagen D. Neuroimmune regulation of homeostatic synaptic plasticity. Neuropharmacology 2013; 78:13-22. [PMID: 23774138 DOI: 10.1016/j.neuropharm.2013.06.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/28/2013] [Accepted: 06/02/2013] [Indexed: 01/08/2023]
Abstract
Homeostatic synaptic plasticity refers to a set of negative-feedback mechanisms that are used by neurons to maintain activity within a functional range. While it is becoming increasingly clear that homeostatic regulation of synapse function is a key principle in the nervous system, the molecular details of this regulation are only beginning to be uncovered. Recent evidence implicates molecules classically associated with the peripheral immune system in the modulation of homeostatic synaptic plasticity. In particular, the pro-inflammatory cytokine TNFα, class I major histocompatibility complex, and neuronal pentraxin 2 are essential in the regulation of the compensatory synaptic response that occurs in response to prolonged neuronal inactivity. This review will present and discuss current evidence implicating neuroimmune molecules in the homeostatic regulation of synapse function. This article is part of the Special Issue entitled 'Homeostatic Synaptic Plasticity'.
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Affiliation(s)
- Horia Pribiag
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montreal General Hospital, L7-132, 1650 Cedar Av, Montreal, QC H3G 1A4, Canada
| | - David Stellwagen
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montreal General Hospital, L7-132, 1650 Cedar Av, Montreal, QC H3G 1A4, Canada.
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Markan CM, Gupta P, Bansal M. An adaptive neuromorphic model of ocular dominance map using floating gate 'synapse'. Neural Netw 2013; 45:117-33. [PMID: 23648171 DOI: 10.1016/j.neunet.2013.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 04/02/2013] [Accepted: 04/04/2013] [Indexed: 11/28/2022]
Abstract
A novel analogue CMOS design of a cortical cell, that computes weighted sum of inputs, is presented. The cell's feedback regime exploits the adaptation dynamics of floating gate pFET 'synapse' to perform competitive learning amongst input weights as time-staggered winner take all. A learning rate parameter regulates adaptation time and a bias enforces resource limitation by restricting the number of input branches and winners in a competition. When learning ends, the cell's response favours one input pattern over others to exhibit feature selectivity. Embedded in a 2-D RC grid, these feature selective cells are capable of performing a symmetry breaking pattern formation, observed in some reaction-diffusion models of cortical feature map formation, e.g. ocular dominance. Close similarity with biological networks in terms of adaptability and long term memory indicates that the cell's design is ideally suited for analogue VLSI implementation of Self-Organizing Feature Map (SOFM) models of cortical feature maps.
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Affiliation(s)
- C M Markan
- Department of Physics & Computer Science, Dayalbagh Educational Institute (Deemed University), Dayalbagh, Agra-282005, India.
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