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Moyal R, Bhamani C, Edelman S. Revisiting the effects of configuration, predictability, and relevance on visual detection during interocular suppression. Cognition 2023; 238:105506. [PMID: 37300930 DOI: 10.1016/j.cognition.2023.105506] [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: 04/23/2022] [Revised: 05/17/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023]
Abstract
Statistical regularities and predictions can influence the earliest stages of visual processing. Studies examining their effects on detection, however, have yielded inconsistent results. In continuous flash suppression (CFS), where a static image projected to one eye is suppressed by a dynamic image presented to the other, the predictability of the suppressed signal may facilitate or delay detection. To identify the factors that differentiate these outcomes and dissociate the effects of expectation from those of behavioral relevance, we conducted three CFS experiments that addressed confounds related to the use of reaction time measures and complex images. In experiment 1, orientation recognition performance and visibility rates increased when a suppressed line segment completed a partial shape surrounding the CFS patch, demonstrating that valid configuration cues facilitate detection. In Experiment 2, however, predictive cues marginally affected visibility and did not modulate localization performance, challenging existing findings. In experiment 3, a relevance manipulation was introduced; participants pressed a key upon detecting lines of a particular orientation, ignoring the other possible orientation. Visibility and localization were enhanced for relevant orientations. Predictive cues modulated visibility, orientation recognition sensitivity, and response latencies, but not localization-an objective measure sensitive to partial breakthrough. Thus, while a consistent surround can strongly enhance detection during passive observation, predictive cueing primarily affects post-detection factors such as response readiness and recognition confidence. Relevance and predictability did not interact, suggesting that the contributions of these two processes to detection are mostly orthogonal.
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Affiliation(s)
- Roy Moyal
- Department of Psychology & Cognitive Science Program, Cornell University, Ithaca, NY, United States of America.
| | - Conrad Bhamani
- Department of Psychology & Cognitive Science Program, Cornell University, Ithaca, NY, United States of America
| | - Shimon Edelman
- Department of Psychology & Cognitive Science Program, Cornell University, Ithaca, NY, United States of America
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2
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Andersen LM, Vinding MC, Sandberg K, Overgaard M. Task requirements affect the neural correlates of consciousness. Eur J Neurosci 2022; 56:5810-5822. [PMID: 36086829 PMCID: PMC9827982 DOI: 10.1111/ejn.15820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/16/2022] [Accepted: 08/30/2022] [Indexed: 01/12/2023]
Abstract
In the search for the neural correlates of consciousness, it is often assumed that there is a stable set within the relevant sensory modality. Within the visual modality, the debate has centred upon whether frontal or occipital activations are the best predictors of perceptual awareness. Although not accepted by all as definitive evidence, no-report and decoding studies have indicated that occipital activity is the most consistently correlated with perceptual awareness whereas frontal activity might be closely related to aspects of cognition typically related to reports. However, perception is rarely just passive perception of something, but more or less always perception for something. That is, the task at hand for the perceiver may influence what is being perceived. This suggests an alternative view: that consciousness is not one specific 'function' that can be localized consistently to one area or event-related component and that the specific attributes of the neural correlates of consciousness depend on the task at hand. To investigate whether and how tasks may influence the neural correlates of consciousness, we here contrasted two tasks, a perceptual task and a conceptual task, using identical stimuli in both tasks. Using magnetoencephalography, we found that the perceptual task recruited more occipital resources than the conceptual task. Furthermore, we found that between the two conditions, the amount of frontal resources recruited differed between different gradations of perceptual awareness partly in an unexpected manner. These findings support a view of task affecting the neural correlates of consciousness.
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Affiliation(s)
- Lau M. Andersen
- Center of Functionally Integrative NeuroscienceAarhus UniversityAarhusDenmark,Aarhus Institute of Advanced Studies (AIAS)Aarhus UniversityAarhusDenmark,Department of Linguistics, Cognitive Science and SemioticsAarhus UniversityAarhusDenmark
| | - Mikkel C. Vinding
- NatMEG, Department of Clinical NeuroscienceKarolinska InstitutetStockholmSweden,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and ResearchCopenhagen University Hospital—Amager and HvidovreCopenhagenDenmark
| | - Kristian Sandberg
- Center of Functionally Integrative NeuroscienceAarhus UniversityAarhusDenmark
| | - Morten Overgaard
- Center of Functionally Integrative NeuroscienceAarhus UniversityAarhusDenmark
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3
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Jeffrey BG, Flynn OJ, Huryn LA, Pfau M, Cukras CA. Scotopic Contour Deformation Detection Reveals Early Rod Dysfunction in Age-Related Macular Degeneration With and Without Reticular Pseudodrusen. Invest Ophthalmol Vis Sci 2022; 63:23. [PMID: 35749129 PMCID: PMC9234356 DOI: 10.1167/iovs.63.6.23] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to investigate scotopic contour deformation detection (sCDD), and its structural determinants, in participants with intermediate age-related macular degeneration (iAMD) with or without reticular pseudodrusen (RPD). Methods Forty-one participants (aged 58–89 years), including 9 with iAMD and RPD, 16 with iAMD only, and 16 controls, underwent functional testing. The sCDD was evaluated with radial frequency arcs presented at 4 loci: ±4 degrees and 8 degrees vertical eccentricity. Scotopic thresholds and dark adaptation (DA) were measured at the same loci. Retinal layers of spectral domain optical coherence tomography (SD-OCT) volume scans were segmented. To establish the concurrent validity of the functional test, we evaluated the fraction of variability in sCDD thresholds explained by SD-OCT data. Results The iAMD group had significantly worse sCDD thresholds compared with controls (8 degrees inferior retina: P = 0.004 and the 4 degrees loci: P < 0.02 for both). Elevated sCDD thresholds were observed in iAMD and RPD eyes at loci with normal scotopic thresholds; the opposite was rarely encountered. Elevated sCDD thresholds were also observed in iAMD eyes with normal DA. Elevated sCDD thresholds were associated with increased age and presence of late AMD in the fellow eye. The optimal machine learning model predicted 16% of variability (cross-validated R2) in sCDD thresholds at 8 degrees. Discussion A novel scotopic contour deformation task can provide unique information about rod dysfunction in participants with iAMD and RPD not observed with structural and other functional assessments. Rod dysfunction observed with scotopic contour deformation testing was associated with factors linked to risk of AMD progression.
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Affiliation(s)
- Brett G Jeffrey
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Oliver J Flynn
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Laryssa A Huryn
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Maximilian Pfau
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States.,University of Bonn, Bonn, Germany
| | - Catherine A Cukras
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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4
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Ho HT, Burr DC, Alais D, Morrone MC. Propagation and update of auditory perceptual priors through alpha and theta rhythms. Eur J Neurosci 2021; 55:3083-3099. [PMID: 33559266 PMCID: PMC9543013 DOI: 10.1111/ejn.15141] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 01/05/2021] [Accepted: 01/28/2021] [Indexed: 12/15/2022]
Abstract
To maintain a continuous and coherent percept over time, the brain makes use of past sensory information to anticipate forthcoming stimuli. We recently showed that auditory experience of the immediate past is propagated through ear-specific reverberations, manifested as rhythmic fluctuations of decision bias at alpha frequencies. Here, we apply the same time-resolved behavioural method to investigate how perceptual performance changes over time under conditions of stimulus expectation and to examine the effect of unexpected events on behaviour. As in our previous study, participants were required to discriminate the ear-of-origin of a brief monaural pure tone embedded in uncorrelated dichotic white noise. We manipulated stimulus expectation by increasing the target probability in one ear to 80%. Consistent with our earlier findings, performance did not remain constant across trials, but varied rhythmically with delay from noise onset. Specifically, decision bias showed a similar oscillation at ~9 Hz, which depended on ear congruency between successive targets. This suggests rhythmic communication of auditory perceptual history occurs early and is not readily influenced by top-down expectations. In addition, we report a novel observation specific to infrequent, unexpected stimuli that gave rise to oscillations in accuracy at ~7.6 Hz one trial after the target occurred in the non-anticipated ear. This new behavioural oscillation may reflect a mechanism for updating the sensory representation once a prediction error has been detected.
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Affiliation(s)
- Hao Tam Ho
- School of Psychology, University of Sydney, Camperdown, NSW, Australia.,Department of Neuroscience, Psychology, Pharmacology, and Child Health, University of Florence, Florence, Italy
| | - David C Burr
- School of Psychology, University of Sydney, Camperdown, NSW, Australia.,Department of Neuroscience, Psychology, Pharmacology, and Child Health, University of Florence, Florence, Italy.,Institute of Neuroscience, Pisa, Italy
| | - David Alais
- School of Psychology, University of Sydney, Camperdown, NSW, Australia
| | - Maria Concetta Morrone
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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5
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The Do's and Don'ts of Psychophysical Methods for Interpretability of Psychometric Functions and Their Descriptors. SPANISH JOURNAL OF PSYCHOLOGY 2019; 22:E56. [PMID: 31868158 DOI: 10.1017/sjp.2019.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Many areas of research require measuring psychometric functions or their descriptors (thresholds, slopes, etc.). Data for this purpose are collected with psychophysical methods of various types and justification for the interpretation of results arises from a model of performance grounded in signal detection theory. Decades of research have shown that psychophysical data display features that are incompatible with such framework, questioning the validity of interpretations obtained under it and revealing that psychophysical performance is more complex than this framework entertains. This paper describes the assumptions and formulation of the conventional framework for the two major classes of psychophysical methods (single- and dual-presentation methods) and presents various lines of empirical evidence that the framework is inconsistent with. An alternative framework is then described and shown to account for all the characteristics that the conventional framework regards as anomalies. This alternative process model explicitly separates the sensory, decisional, and response components of performance and represents them via parameters whose estimation characterizes the corresponding processes. Retrospective and prospective evidence of the validity of the alternative framework is also presented. A formal analysis also reveals that some psychophysical methods and response formats are unsuitable for separation of the three components of observed performance. Recommendations are thus given regarding practices that should be avoided and those that should be followed to ensure interpretability of the psychometric function, or descriptors (detection threshold, difference limen, point of subjective equality, etc.) obtained with shortcut methods that do not require estimation of psychometric functions.
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6
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Ho HT, Burr DC, Alais D, Morrone MC. Auditory Perceptual History Is Propagated through Alpha Oscillations. Curr Biol 2019; 29:4208-4217.e3. [PMID: 31761705 PMCID: PMC6926473 DOI: 10.1016/j.cub.2019.10.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/30/2019] [Accepted: 10/21/2019] [Indexed: 01/24/2023]
Abstract
Perception is a proactive, “predictive” process, in which the brain relies, at least in part, on accumulated experience to make best guesses about the world to test against sensory data, updating the guesses as new experience is acquired. Using novel behavioral methods, the present study demonstrates the role of alpha rhythms in communicating past perceptual experience. Participants were required to discriminate the ear of origin of brief sinusoidal tones that were presented monaurally at random times within a burst of uncorrelated dichotic white noise masks. Performance was not constant but varied with delay after noise onset in an oscillatory manner at about 9 Hz (alpha rhythm). Importantly, oscillations occurred only for trials preceded by a target tone to the same ear, either on the previous trial or two trials back. These results suggest that communication of perceptual history generates neural oscillations within specific perceptual circuits, strongly implicating behavioral oscillations in predictive perception and with formation of working memory. We demonstrate the role of alpha rhythms in the propagation of perceptual history Auditory decisions were rhythmically biased by stimuli presented 1 or 2 trials back Bias oscillated at ∼9 Hz only when successive stimuli occurred in the same ear Alpha is strongly implicated in predictive perception and working memory formation
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Affiliation(s)
- Hao Tam Ho
- School of Psychology, University of Sydney, Brennan MacCallum Building A18, Manning Road, Camperdown, NSW 2006, Australia; Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Via San Zeno 31, 56123 Pisa, Italy.
| | - David C Burr
- School of Psychology, University of Sydney, Brennan MacCallum Building A18, Manning Road, Camperdown, NSW 2006, Australia; Department of Neuroscience, Psychology, Pharmacology, and Child Health, University of Florence, Via di San Salvi 12, 50139 Florence, Italy; Institute of Neuroscience, Via Giuseppe Moruzzi 1, 56124 Pisa, Italy.
| | - David Alais
- School of Psychology, University of Sydney, Brennan MacCallum Building A18, Manning Road, Camperdown, NSW 2006, Australia
| | - Maria Concetta Morrone
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Via San Zeno 31, 56123 Pisa, Italy
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7
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Marasco PD, Hebert JS, Sensinger JW, Shell CE, Schofield JS, Thumser ZC, Nataraj R, Beckler DT, Dawson MR, Blustein DH, Gill S, Mensh BD, Granja-Vazquez R, Newcomb MD, Carey JP, Orzell BM. Illusory movement perception improves motor control for prosthetic hands. Sci Transl Med 2019. [PMID: 29540617 DOI: 10.1126/scitranslmed.aao6990] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
To effortlessly complete an intentional movement, the brain needs feedback from the body regarding the movement's progress. This largely nonconscious kinesthetic sense helps the brain to learn relationships between motor commands and outcomes to correct movement errors. Prosthetic systems for restoring function have predominantly focused on controlling motorized joint movement. Without the kinesthetic sense, however, these devices do not become intuitively controllable. We report a method for endowing human amputees with a kinesthetic perception of dexterous robotic hands. Vibrating the muscles used for prosthetic control via a neural-machine interface produced the illusory perception of complex grip movements. Within minutes, three amputees integrated this kinesthetic feedback and improved movement control. Combining intent, kinesthesia, and vision instilled participants with a sense of agency over the robotic movements. This feedback approach for closed-loop control opens a pathway to seamless integration of minds and machines.
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Affiliation(s)
- Paul D Marasco
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA. .,Advanced Platform Technology Center of Excellence, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Boulevard 151 W/APT, Cleveland, OH 44106, USA
| | - Jacqueline S Hebert
- Division of Physical Medicine and Rehabilitation, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.,Glenrose Rehabilitation Hospital, Alberta Health Services, 10230-111 Avenue, Edmonton, Alberta T5G 0B7, Canada
| | - Jon W Sensinger
- Institute of Biomedical Engineering, University of New Brunswick, 25 Dineen Drive, Fredericton, New Brunswick E3B 5A3, Canada
| | - Courtney E Shell
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA
| | - Jonathon S Schofield
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA
| | - Zachary C Thumser
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA.,Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Boulevard, Research 151, Cleveland, OH 44106, USA
| | - Raviraj Nataraj
- Department of Biomedical Engineering, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, NJ 07030, USA
| | - Dylan T Beckler
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA
| | - Michael R Dawson
- Glenrose Rehabilitation Hospital, Alberta Health Services, 10230-111 Avenue, Edmonton, Alberta T5G 0B7, Canada
| | - Dan H Blustein
- Institute of Biomedical Engineering, University of New Brunswick, 25 Dineen Drive, Fredericton, New Brunswick E3B 5A3, Canada
| | - Satinder Gill
- Institute of Biomedical Engineering, University of New Brunswick, 25 Dineen Drive, Fredericton, New Brunswick E3B 5A3, Canada
| | - Brett D Mensh
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Rafael Granja-Vazquez
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA
| | - Madeline D Newcomb
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA
| | - Jason P Carey
- Department of Mechanical Engineering, University of Alberta, Donadeo Innovation Center for Engineering, Edmonton, Alberta T6G 2G8, Canada
| | - Beth M Orzell
- Laboratory for Bionic Integration, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA.,Prosthetics and Sensory Aids Service, Department of Physical Medicine and Rehabilitation, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA
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8
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Shehata AW, Scheme EJ, Sensinger JW. Evaluating Internal Model Strength and Performance of Myoelectric Prosthesis Control Strategies. IEEE Trans Neural Syst Rehabil Eng 2019; 26:1046-1055. [PMID: 29752240 DOI: 10.1109/tnsre.2018.2826981] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
On-going developments in myoelectric prosthesis control have provided prosthesis users with an assortment of control strategies that vary in reliability and performance. Many studies have focused on improving performance by providing feedback to the user but have overlooked the effect of this feedback on internal model development, which is key to improve long-term performance. In this paper, the strength of internal models developed for two commonly used myoelectric control strategies: raw control with raw feedback (using a regression-based approach) and filtered control with filtered feedback (using a classifier-based approach), were evaluated using two psychometric measures: trial-by-trial adaptation and just-noticeable difference. The performance of both strategies was also evaluated using Schmidt's style target acquisition task. Results obtained from 24 able-bodied subjects showed that although filtered control with filtered feedback had better short-term performance in path efficiency ( ), raw control with raw feedback resulted in stronger internal model development ( ), which may lead to better long-term performance. Despite inherent noise in the control signals of the regression controller, these findings suggest that rich feedback associated with regression control may be used to improve human understanding of the myoelectric control system.
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9
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Behavioural oscillations in visual orientation discrimination reveal distinct modulation rates for both sensitivity and response bias. Sci Rep 2019; 9:1115. [PMID: 30718679 PMCID: PMC6362039 DOI: 10.1038/s41598-018-37918-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 12/12/2018] [Indexed: 11/08/2022] Open
Abstract
Perception is modulated by ongoing brain oscillations. Psychophysical studies show a voluntary action can synchronize oscillations, producing rhythmical fluctuations of visual contrast sensitivity. We used signal detection to examine whether voluntary action could also synchronize oscillations in decision criterion, and whether that was due to the oscillations of perceptual bias or of motor bias. Trials started with a voluntary button-press. After variable time lags, a grating at threshold contrast was presented briefly and participants discriminated its orientation (45° or −45°) with a mouse-click. Two groups of participants completed the experiment with opposite mappings between grating orientations and response buttons. We calculated sensitivity and criterion in the 800 ms period following the button press. To test for oscillations, we fitted first-order Fourier series to these time series. Alpha oscillations occurred in both sensitivity and criterion at different frequencies: ~8 Hz (sensitivity) and ~10 Hz (criterion). Sensitivity oscillations had the same phase for both stimulus-response mappings. Criterion oscillations, however, showed a strong anti-phase relationship when the two groups were compared, suggesting a motor bias rather than perceptual bias. Our findings suggest two roles for alpha oscillations: in sensitivity, reflecting rhythmic attentional inhibition, and in criterion, indicating dynamic motor-related anticipation or preparation.
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10
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Abstract
Radial frequency (RF) patterns are valuable tools for investigations of contour integration and shape discrimination. Under photopic conditions, healthy observers can detect deformations from circularity in RF patterns as small as 3 seconds of arc. Such fine discrimination may be facilitated by cortical curvature detectors or global shape-detecting mechanisms that favor a closed contour. Rods make up 95% of photoreceptors in the retina, but we know very little about how spatial information is processed by rod-mediated pathways. We measured scotopic radial deformation discrimination using both full and partly occluded RF pattern stimuli. We found radial deformation thresholds of around 2–3 minutes of arc for stimuli with a wide range of radii and RFs. When parts of the stimulus were occluded, scotopic thresholds improved up to the point that three or four cycles of modulation were visible; no further improvement occurred with the addition of more visible cycles. When only one to three cycles were visible, an increase in curvature per cycle became important, allowing observers to detect smaller deformations from circularity. Our results indicate that the scotopic radial deformation thresholds for the stimuli tested are not dependent on global circularity cues but are instead mediated by local curvature cues.
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Affiliation(s)
- Oliver J Flynn
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brett G Jeffrey
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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11
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Enhancing simulations with intra-subject variability for improved psychophysical assessments. PLoS One 2018; 13:e0209839. [PMID: 30596761 PMCID: PMC6312217 DOI: 10.1371/journal.pone.0209839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 12/12/2018] [Indexed: 11/19/2022] Open
Abstract
Psychometric properties of perceptual assessments, like reliability, depend on stochastic properties of psychophysical sampling procedures resulting in method variability, as well as inter- and intra-subject variability. Method variability is commonly minimized by optimizing sampling procedures through computer simulations. Inter-subject variability is inherent to the population of interest and cannot be influenced. Intra-subject variability introduced by confounds (e.g., inattention or lack of motivation) cannot be simply quantified from experimental data, as these data also include method variability. Therefore, this aspect is generally neglected when developing assessments. Yet, comparing method variability and intra-subject variability could give insights on whether effort should be invested in optimizing the sampling procedure, or in addressing potential confounds instead. We propose a new approach to estimate intra-subject variability of psychometric functions by combining computer simulations and behavioral data, and to account for it when simulating experiments. The approach was illustrated in a real-world scenario of proprioceptive difference threshold assessments. The behavioral study revealed a test-retest reliability of r = 0.212. Computer simulations without considering intra-subject variability predicted a reliability of r = 0.768, whereas the new approach including an intra-subject variability model lead to a realistic estimate of reliability (r = 0.207). Such a model also allows computing the theoretically maximally attainable reliability (r = 0.552) assuming an ideal sampling procedure. Comparing the reliability estimates when exclusively accounting for method variability versus intra-subject variability reveals that intra-subject variability should be reduced by addressing confounds and that only optimizing the sampling procedure may be insufficient to achieve a high reliability. This new approach allows computing the intra-subject variability with only two measurements per subject, and predicting the reliability for a larger number of subjects and retests based on simulations, without requiring additional experiments. Such a tool of predictive value is especially valuable for target populations where time is scarce, e.g., for assessments in clinical settings.
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12
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Rinderknecht MD, Lambercy O, Gassert R. Performance metrics for an application-driven selection and optimization of psychophysical sampling procedures. PLoS One 2018; 13:e0207217. [PMID: 30485350 PMCID: PMC6261547 DOI: 10.1371/journal.pone.0207217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 10/26/2018] [Indexed: 01/08/2023] Open
Abstract
When estimating psychometric functions with sampling procedures, psychophysical assessments should be precise and accurate while being as efficient as possible to reduce assessment duration. The estimation performance of sampling procedures is commonly evaluated in computer simulations for single psychometric functions and reported using metrics as a function of number of trials. However, the estimation performance of a sampling procedure may vary for different psychometric functions. Therefore, the results of these type of evaluations may not be generalizable to a heterogeneous population of interest. In addition, the maximum number of trials is often imposed by time restrictions, especially in clinical applications, making trial-based metrics suboptimal. Hence, the benefit of these simulations to select and tune an ideal sampling procedure for a specific application is limited. We suggest to evaluate the estimation performance of sampling procedures in simulations covering the entire range of psychometric functions found in a population of interest, and propose a comprehensive set of performance metrics for a detailed analysis. To illustrate the information gained from these metrics in an application example, six sampling procedures were evaluated in a computer simulation based on prior knowledge on the population distribution and requirements from proprioceptive assessments. The metrics revealed limitations of the sampling procedures, such as inhomogeneous or systematically decreasing performance depending on the psychometric functions, which can inform the tuning process of a sampling procedure. More advanced metrics allowed directly comparing overall performances of different sampling procedures and select the best-suited sampling procedure for the example application. The proposed analysis metrics can be used for any sampling procedure and the estimation of any parameter of a psychometric function, independent of the shape of the psychometric function and of how such a parameter was estimated. This framework should help to accelerate the development process of psychophysical assessments.
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Affiliation(s)
- Mike D. Rinderknecht
- Rehabilitation Engineering Laboratory, Institute of Robotics and Intelligent Systems, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Olivier Lambercy
- Rehabilitation Engineering Laboratory, Institute of Robotics and Intelligent Systems, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Roger Gassert
- Rehabilitation Engineering Laboratory, Institute of Robotics and Intelligent Systems, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
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13
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Archer-Boyd AW, Southwell RV, Deeks JM, Turner RE, Carlyon RP. Development and validation of a spectro-temporal processing test for cochlear-implant listeners. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:2983. [PMID: 30522311 PMCID: PMC6805218 DOI: 10.1121/1.5079636] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 11/01/2018] [Indexed: 06/06/2023]
Abstract
Psychophysical tests of spectro-temporal resolution may aid the evaluation of methods for improving hearing by cochlear implant (CI) listeners. Here the STRIPES (Spectro-Temporal Ripple for Investigating Processor EffectivenesS) test is described and validated. Like speech, the test requires both spectral and temporal processing to perform well. Listeners discriminate between complexes of sine sweeps which increase or decrease in frequency; difficulty is controlled by changing the stimulus spectro-temporal density. Care was taken to minimize extraneous cues, forcing listeners to perform the task only on the direction of the sweeps. Vocoder simulations with normal hearing listeners showed that the STRIPES test was sensitive to the number of channels and temporal information fidelity. An evaluation with CI listeners compared a standard processing strategy with one having very wide filters, thereby spectrally blurring the stimulus. Psychometric functions were monotonic for both strategies and five of six participants performed better with the standard strategy. An adaptive procedure revealed significant differences, all in favour of the standard strategy, at the individual listener level for six of eight CI listeners. Subsequent measures validated a faster version of the test, and showed that STRIPES could be performed by recently implanted listeners having no experience of psychophysical testing.
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Affiliation(s)
- Alan W. Archer-Boyd
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - Rosy V. Southwell
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - John M. Deeks
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - Richard E. Turner
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - Robert P. Carlyon
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
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Ferrari F, Clemente F, Cipriani C. The preload force affects the perception threshold of muscle vibration-induced movement illusions. Exp Brain Res 2018; 237:111-120. [PMID: 30341466 PMCID: PMC6514251 DOI: 10.1007/s00221-018-5402-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 10/12/2018] [Indexed: 11/12/2022]
Abstract
The control and the execution of motor tasks are largely influenced by proprioceptive feedback, i.e. the information about the position and movement of the body. In 1972, it was discovered that a vibratory stimulation applied non-invasively to a muscle or a tendon induces a movement illusion consistent with the elongation of the vibrated muscle/tendon. Although this phenomenon was reported by several studies, it is still unclear how to reliably reproduce it because of the many different features of the stimulation altering the sensation (e.g. frequency, duration, location). By performing a psychophysical test, we analysed the effects of the stimulation point and the preload force on the minimum stimulation amplitude needed to elicit an illusion of movement. In particular, we stimulated two groups of healthy subjects on three target regions of the biceps brachii muscle (the distal tendon, the muscle belly and one of the proximal tendons) applying three preload force ranges (0.5–0.75N, 1–2N and 3–4N). Our results showed that the minimum stimulation amplitude eliciting a sensation is affected by the preload force. On the contrary, it did not change significantly among the three stimulated regions. Nevertheless, the reported vividness of the illusion of movement changed across the stimulated points decreasing while moving from the distal to the proximal tendons. Overall, these outcomes contribute to the scientific debate on the features that modulate the vibration-induced movement illusion proposing ways to increase the reliability of the procedure in basic and applied research studies.
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Affiliation(s)
- Francesca Ferrari
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio, 34, 56025, Pontedera, PI, Italy.
| | - Francesco Clemente
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio, 34, 56025, Pontedera, PI, Italy
| | - Christian Cipriani
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio, 34, 56025, Pontedera, PI, Italy
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15
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Shehata AW, Engels LF, Controzzi M, Cipriani C, Scheme EJ, Sensinger JW. Improving internal model strength and performance of prosthetic hands using augmented feedback. J Neuroeng Rehabil 2018; 15:70. [PMID: 30064477 PMCID: PMC6069837 DOI: 10.1186/s12984-018-0417-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/17/2018] [Indexed: 11/24/2022] Open
Abstract
Background The loss of an arm presents a substantial challenge for upper limb amputees when performing activities of daily living. Myoelectric prosthetic devices partially replace lost hand functions; however, lack of sensory feedback and strong understanding of the myoelectric control system prevent prosthesis users from interacting with their environment effectively. Although most research in augmented sensory feedback has focused on real-time regulation, sensory feedback is also essential for enabling the development and correction of internal models, which in turn are used for planning movements and reacting to control variability faster than otherwise possible in the presence of sensory delays. Methods Our recent work has demonstrated that audio-augmented feedback can improve both performance and internal model strength for an abstract target acquisition task. Here we use this concept in controlling a robotic hand, which has inherent dynamics and variability, and apply it to a more functional grasp-and-lift task. We assessed internal model strength using psychophysical tests and used an instrumented Virtual Egg to assess performance. Results Results obtained from 14 able-bodied subjects show that a classifier-based controller augmented with audio feedback enabled stronger internal model (p = 0.018) and better performance (p = 0.028) than a controller without this feedback. Conclusions We extended our previous work and accomplished the first steps on a path towards bridging the gap between research and clinical usability of a hand prosthesis. The main goal was to assess whether the ability to decouple internal model strength and motion variability using the continuous audio-augmented feedback extended to real-world use, where the inherent mechanical variability and dynamics in the mechanisms may contribute to a more complicated interplay between internal model formation and motion variability. We concluded that benefits of using audio-augmented feedback for improving internal model strength of myoelectric controllers extend beyond a virtual target acquisition task to include control of a prosthetic hand.
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Affiliation(s)
- Ahmed W Shehata
- Institute of Biomedical Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada. .,Department of Electrical and Computer Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada. .,Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
| | - Leonard F Engels
- Scuola Superiore Sant'Anna, The BioRobotics Institute, V.le R. Piaggio 34, 56025, Pontedera, PI, Italy
| | - Marco Controzzi
- Scuola Superiore Sant'Anna, The BioRobotics Institute, V.le R. Piaggio 34, 56025, Pontedera, PI, Italy
| | - Christian Cipriani
- Scuola Superiore Sant'Anna, The BioRobotics Institute, V.le R. Piaggio 34, 56025, Pontedera, PI, Italy
| | - Erik J Scheme
- Institute of Biomedical Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada.,Department of Electrical and Computer Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada
| | - Jonathon W Sensinger
- Institute of Biomedical Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada.,Department of Electrical and Computer Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada
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16
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Shehata AW, Scheme EJ, Sensinger JW. Audible Feedback Improves Internal Model Strength and Performance of Myoelectric Prosthesis Control. Sci Rep 2018; 8:8541. [PMID: 29867147 PMCID: PMC5986794 DOI: 10.1038/s41598-018-26810-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 05/21/2018] [Indexed: 12/01/2022] Open
Abstract
Myoelectric prosthetic devices are commonly used to help upper limb amputees perform activities of daily living, however amputees still lack the sensory feedback required to facilitate reliable and precise control. Augmented feedback may play an important role in affecting both short-term performance, through real-time regulation, and long-term performance, through the development of stronger internal models. In this work, we investigate the potential tradeoff between controllers that enable better short-term performance and those that provide sufficient feedback to develop a strong internal model. We hypothesize that augmented feedback may be used to mitigate this tradeoff, ultimately improving both short and long-term control. We used psychometric measures to assess the internal model developed while using a filtered myoelectric controller with augmented audio feedback, imitating classification-based control but with augmented regression-based feedback. In addition, we evaluated the short-term performance using a multi degree-of-freedom constrained-time target acquisition task. Results obtained from 24 able-bodied subjects show that an augmented feedback control strategy using audio cues enables the development of a stronger internal model than the filtered control with filtered feedback, and significantly better path efficiency than both raw and filtered control strategies. These results suggest that the use of augmented feedback control strategies may improve both short-term and long-term performance.
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Affiliation(s)
- Ahmed W Shehata
- University of New Brunswick, Electrical and Computer Engineering, Fredericton, E3B5A3, Canada.
- Institute of Biomedical Engineering, Fredericton, E3B5A3, Canada.
| | - Erik J Scheme
- University of New Brunswick, Electrical and Computer Engineering, Fredericton, E3B5A3, Canada
- Institute of Biomedical Engineering, Fredericton, E3B5A3, Canada
| | - Jonathon W Sensinger
- University of New Brunswick, Electrical and Computer Engineering, Fredericton, E3B5A3, Canada
- Institute of Biomedical Engineering, Fredericton, E3B5A3, Canada
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17
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Blustein DH, Sensinger JW. Validation of a constrained-time movement task for use in rehabilitation outcome measures. IEEE Int Conf Rehabil Robot 2018; 2017:1183-1188. [PMID: 28813982 DOI: 10.1109/icorr.2017.8009410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Current motor assessment tools can provide numerical indicators of performance but do not provide actionable information to target further improvement in rehabilitation interventions. Psychophysics-based outcome measures show promise to provide more useful information in the laboratory environment but have been limited in clinical implementation. Here we present a constrained-time task to assess paced and non-rhythmic movements. The task's output metrics include trial-by-trial adaptation rate and the just noticeable difference of a perturbation. We show that the task's metrics are reliable (i.e. high test-retest reliability) and are responsive to changes in feedback type and experience. We also discuss the task's versatility to be used for other types of movements including grasping. The consistent, sensitive and flexible time-constrained movement task we present provides a foundation from which to develop advanced outcome measures for prosthesis users and for other rehabilitation contexts.
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18
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Ho HT, Leung J, Burr DC, Alais D, Morrone MC. Auditory Sensitivity and Decision Criteria Oscillate at Different Frequencies Separately for the Two Ears. Curr Biol 2017; 27:3643-3649.e3. [DOI: 10.1016/j.cub.2017.10.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/15/2017] [Accepted: 10/05/2017] [Indexed: 10/18/2022]
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19
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Ferrari U, Gardella C, Marre O, Mora T. Closed-Loop Estimation of Retinal Network Sensitivity by Local Empirical Linearization. eNeuro 2017; 4:ENEURO.0166-17.2017. [PMID: 29379871 PMCID: PMC5783239 DOI: 10.1523/eneuro.0166-17.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 10/12/2017] [Accepted: 10/16/2017] [Indexed: 11/28/2022] Open
Abstract
Understanding how sensory systems process information depends crucially on identifying which features of the stimulus drive the response of sensory neurons, and which ones leave their response invariant. This task is made difficult by the many nonlinearities that shape sensory processing. Here, we present a novel perturbative approach to understand information processing by sensory neurons, where we linearize their collective response locally in stimulus space. We added small perturbations to reference stimuli and tested if they triggered visible changes in the responses, adapting their amplitude according to the previous responses with closed-loop experiments. We developed a local linear model that accurately predicts the sensitivity of the neural responses to these perturbations. Applying this approach to the rat retina, we estimated the optimal performance of a neural decoder and showed that the nonlinear sensitivity of the retina is consistent with an efficient encoding of stimulus information. Our approach can be used to characterize experimentally the sensitivity of neural systems to external stimuli locally, quantify experimentally the capacity of neural networks to encode sensory information, and relate their activity to behavior.
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Affiliation(s)
- Ulisse Ferrari
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, 75012 Paris, France
| | - Christophe Gardella
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, 75012 Paris, France
- Laboratoire de physique statistique, CNRS, Sorbonne Université, Université Paris-Diderot and École normale supérieure (PSL), 24, rue Lhomond, 75005 Paris, France
| | - Olivier Marre
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, 75012 Paris, France
| | - Thierry Mora
- Laboratoire de physique statistique, CNRS, Sorbonne Université, Université Paris-Diderot and École normale supérieure (PSL), 24, rue Lhomond, 75005 Paris, France
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20
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Johnson RE, Kording KP, Hargrove LJ, Sensinger JW. EMG Versus Torque Control of Human–Machine Systems: Equalizing Control Signal Variability Does not Equalize Error or Uncertainty. IEEE Trans Neural Syst Rehabil Eng 2017; 25:660-667. [DOI: 10.1109/tnsre.2016.2598095] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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21
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Clemente F, Håkansson B, Cipriani C, Wessberg J, Kulbacka-Ortiz K, Brånemark R, Fredén Jansson KJ, Ortiz-Catalan M. Touch and Hearing Mediate Osseoperception. Sci Rep 2017; 7:45363. [PMID: 28349945 PMCID: PMC5368565 DOI: 10.1038/srep45363] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/27/2017] [Indexed: 12/24/2022] Open
Abstract
Osseoperception is the sensation arising from the mechanical stimulation of a bone-anchored prosthesis. Here we show that not only touch, but also hearing is involved in this phenomenon. Using mechanical vibrations ranging from 0.1 to 6 kHz, we performed four psychophysical measures (perception threshold, sensation discrimination, frequency discrimination and reaction time) on 12 upper and lower limb amputees and found that subjects: consistently reported perceiving a sound when the stimulus was delivered at frequencies equal to or above 400 Hz; were able to discriminate frequency differences between stimuli delivered at high stimulation frequencies (~1500 Hz); improved their reaction time for bimodal stimuli (i.e. when both vibration and sound were perceived). Our results demonstrate that osseoperception is a multisensory perception, which can explain the improved environment perception of bone-anchored prosthesis users. This phenomenon might be exploited in novel prosthetic devices to enhance their control, thus ultimately improving the amputees' quality of life.
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Affiliation(s)
| | - Bo Håkansson
- Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Johan Wessberg
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Katarzyna Kulbacka-Ortiz
- Centre for Advanced Reconstruction of Extremities, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Rickard Brånemark
- Centre for Advanced Reconstruction of Extremities, Sahlgrenska University Hospital, Gothenburg, Sweden.,International Center for Osseointegration Research, Education and Surgery (iCORES), Department of Orthopaedics, University of California, San Francisco, USA
| | | | - Max Ortiz-Catalan
- Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden.,Integrum AB, Gothenburg, Sweden
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22
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García-Pérez MA. Does time ever fly or slow down? The difficult interpretation of psychophysical data on time perception. Front Hum Neurosci 2014; 8:415. [PMID: 24959133 PMCID: PMC4051264 DOI: 10.3389/fnhum.2014.00415] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 05/23/2014] [Indexed: 11/13/2022] Open
Abstract
Time perception is studied with subjective or semi-objective psychophysical methods. With subjective methods, observers provide quantitative estimates of duration and data depict the psychophysical function relating subjective duration to objective duration. With semi-objective methods, observers provide categorical or comparative judgments of duration and data depict the psychometric function relating the probability of a certain judgment to objective duration. Both approaches are used to study whether subjective and objective time run at the same pace or whether time flies or slows down under certain conditions. We analyze theoretical aspects affecting the interpretation of data gathered with the most widely used semi-objective methods, including single-presentation and paired-comparison methods. For this purpose, a formal model of psychophysical performance is used in which subjective duration is represented via a psychophysical function and the scalar property. This provides the timing component of the model, which is invariant across methods. A decisional component that varies across methods reflects how observers use subjective durations to make judgments and give the responses requested under each method. Application of the model shows that psychometric functions in single-presentation methods are uninterpretable because the various influences on observed performance are inextricably confounded in the data. In contrast, data gathered with paired-comparison methods permit separating out those influences. Prevalent approaches to fitting psychometric functions to data are also discussed and shown to be inconsistent with widely accepted principles of time perception, implicitly assuming instead that subjective time equals objective time and that observed differences across conditions do not reflect differences in perceived duration but criterion shifts. These analyses prompt evidence-based recommendations for best methodological practice in studies on time perception.
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Affiliation(s)
- Miguel A. García-Pérez
- Departamento de Metodología, Facultad de Psicología, Universidad ComplutenseMadrid, Spain
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23
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Adaptive psychophysical methods for nonmonotonic psychometric functions. Atten Percept Psychophys 2013; 76:621-41. [DOI: 10.3758/s13414-013-0574-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Psychophysical estimates of frequency discrimination: more than just limitations of auditory processing. Brain Sci 2013; 3:1023-42. [PMID: 24961519 PMCID: PMC4061867 DOI: 10.3390/brainsci3031023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 05/20/2013] [Accepted: 06/14/2013] [Indexed: 12/01/2022] Open
Abstract
Efficient auditory processing is hypothesized to support language and literacy development. However, behavioral tasks used to assess this hypothesis need to be robust to non-auditory specific individual differences. This study compared frequency discrimination abilities in a heterogeneous sample of adults using two different psychoacoustic task designs, referred to here as: 2I_6A_X and 3I_2AFC designs. The role of individual differences in nonverbal IQ (NVIQ), socioeconomic status (SES) and musical experience in predicting frequency discrimination thresholds on each task were assessed using multiple regression analyses. The 2I_6A_X task was more cognitively demanding and hence more susceptible to differences specifically in SES and musical training. Performance on this task did not, however, relate to nonword repetition ability (a measure of language learning capacity). The 3I_2AFC task, by contrast, was only susceptible to musical training. Moreover, thresholds measured using it predicted some variance in nonword repetition performance. This design thus seems suitable for use in studies addressing questions regarding the role of auditory processing in supporting language and literacy development.
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25
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Beattie RL, Lu ZL, Manis FR. Dyslexic adults can learn from repeated stimulus presentation but have difficulties in excluding external noise. PLoS One 2011; 6:e27893. [PMID: 22132164 PMCID: PMC3223213 DOI: 10.1371/journal.pone.0027893] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 10/27/2011] [Indexed: 11/19/2022] Open
Abstract
We examined whether the characteristic impairments of dyslexia are due to a deficit in excluding external noise or a deficit in taking advantage of repeated stimulus presentation. We compared non-impaired adults and adults with poor reading performance on a visual letter detection task that varied two aspects: the presence or absence of background visual noise, and a small or large stimulus set. There was no interaction between group and stimulus set size, indicating that the poor readers took advantage of repeated stimulus presentation as well as the non-impaired readers. The poor readers had higher thresholds than non-impaired readers in the presence of high external noise, but not in the absence of external noise. The results support the hypothesis that an external noise exclusion deficit, not a perceptual anchoring deficit, impairs reading for adults.
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Affiliation(s)
- Rachel L Beattie
- Department of Psychology, University of Southern California, Los Angeles, California, United States of America.
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26
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García-Pérez MA. A cautionary note on the use of the adaptive up-down method. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 130:2098-107. [PMID: 21973364 DOI: 10.1121/1.3628334] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Up-down staircases with equal sizes for the steps up and down are widely used to estimate detection and discrimination thresholds in psychoacoustics, but the conventional average-of-reversals estimator does not converge on its presumed percent point in Yes-No tasks or in two-alternative forced-choice detection tasks. The particular percent point of convergence is partly determined by the relative size of the steps with respect to the spread (inverse of slope) of the underlying psychometric function. In particular, threshold is increasingly underestimated as the spread of the psychometric function decreases. This characteristic may have serious consequences when thresholds estimated via up-down staircases are compared across conditions in which the spread of the psychometric function varies, because then these thresholds do not represent comparable measures of performance. This paper documents the misbehavior of the average-of-reversals estimator under up-down rules and types of forced-choice task that are in common use in psychoacoustics but which have not been studied before in simulations. It is also shown that a relatively simple modification of the up-down design (namely, using steps up and down of different size and in a certain ratio depending only on the task and the up-down rule being used) stabilizes the performance of these staircases.
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Affiliation(s)
- Miguel A García-Pérez
- Departamento de Metodología, Facultad de Psicología, Universidad Complutense, Campus de Somosaguas, 28223 Madrid, Spain.
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27
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Psychometric functions for detection and discrimination with and without flankers. Atten Percept Psychophys 2011; 73:829-53. [PMID: 21264745 DOI: 10.3758/s13414-010-0080-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent studies have reported that flanking stimuli broaden the psychometric function and lower detection thresholds. In the present study, we measured psychometric functions for detection and discrimination with and without flankers to investigate whether these effects occur throughout the contrast continuum. Our results confirm that lower detection thresholds with flankers are accompanied by broader psychometric functions. Psychometric functions for discrimination reveal that discrimination thresholds with and without flankers are similar across standard levels, and that the broadening of psychometric functions with flankers disappears as standard contrast increases, to the point that psychometric functions at high standard levels are virtually identical with or without flankers. Threshold-versus-contrast (TvC) curves with flankers only differ from TvC curves without flankers in occasional shallower dippers and lower branches on the left of the dipper, but they run virtually superimposed at high standard levels. We discuss differences between our results and other results in the literature, and how they are likely attributed to the differential vulnerability of alternative psychophysical procedures to the effects of presentation order. We show that different models of flanker facilitation can fit the data equally well, which stresses that succeeding at fitting a model does not validate it in any sense.
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28
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Goldwyn JH, Shea-Brown E, Rubinstein JT. Encoding and decoding amplitude-modulated cochlear implant stimuli--a point process analysis. J Comput Neurosci 2010; 28:405-24. [PMID: 20177761 DOI: 10.1007/s10827-010-0224-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/21/2010] [Accepted: 02/02/2010] [Indexed: 11/25/2022]
Abstract
Cochlear implant speech processors stimulate the auditory nerve by delivering amplitude-modulated electrical pulse trains to intracochlear electrodes. Studying how auditory nerve cells encode modulation information is of fundamental importance, therefore, to understanding cochlear implant function and improving speech perception in cochlear implant users. In this paper, we analyze simulated responses of the auditory nerve to amplitude-modulated cochlear implant stimuli using a point process model. First, we quantify the information encoded in the spike trains by testing an ideal observer's ability to detect amplitude modulation in a two-alternative forced-choice task. We vary the amount of information available to the observer to probe how spike timing and averaged firing rate encode modulation. Second, we construct a neural decoding method that predicts several qualitative trends observed in psychophysical tests of amplitude modulation detection in cochlear implant listeners. We find that modulation information is primarily available in the sequence of spike times. The performance of an ideal observer, however, is inconsistent with observed trends in psychophysical data. Using a neural decoding method that jitters spike times to degrade its temporal resolution and then computes a common measure of phase locking from spike trains of a heterogeneous population of model nerve cells, we predict the correct qualitative dependence of modulation detection thresholds on modulation frequency and stimulus level. The decoder does not predict the observed loss of modulation sensitivity at high carrier pulse rates, but this framework can be applied to future models that better represent auditory nerve responses to high carrier pulse rate stimuli. The supplemental material of this article contains the article's data in an active, re-usable format.
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Affiliation(s)
- Joshua H Goldwyn
- Department of Applied Mathematics, University of Washington, Seattle, WA, USA.
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29
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Sensinger JW, Schultz AE, Kuiken TA. Examination of force discrimination in human upper limb amputees with reinnervated limb sensation following peripheral nerve transfer. IEEE Trans Neural Syst Rehabil Eng 2009; 17:438-44. [PMID: 19775983 DOI: 10.1109/tnsre.2009.2032640] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Artificial limbs allow amputees to manipulate objects, but the loss of a limb severs the sensory link between a subject and objects they touch. A novel surgical technique we term targeted reinnervation (TR) allows severed cutaneous nerves to reinnervate skin on a different portion of the body. This technique provides a physiologically appropriate portal to the sensory pathways of the missing limb through the reinnervated skin. This study quantified the ability of three amputee subjects who had undergone TR surgery on the chest (two subjects) and upper arm (one subject) to discriminate changes in graded force on their reinnervated skin over a range of 1-4 N using a stochastic staircase approach. These values were compared to those from sites on their intact contralateral skin and index fingers, and from the chests and index fingers of a control population (n = 10) . Weber's ratio (WR) was used to examine the subjects' abilities to discriminate between a baseline force and subsequent forces of different magnitudes. WRs of 0.22, 0.25, and 0.12 were measured on the reinnervated skin of the three TR subjects, whereas WRs of 0.25, 0.23, and 0.12 were measured on their contralateral skin. TR subjects did not have substantially different WRs on their reinnervated versus their contralateral normal side and did not appear to exhibit a trend towards impaired sensation. No significant difference was found between the WR of the chest and index finger of the control subjects, which ranged between 0.09 and 0.21. WR of reinnervated skin for TR subjects were within the 95% confidence interval of the control group. These data suggest that subjects with targeted reinnervation have unimpaired ability to discriminate gradations in force.
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Affiliation(s)
- Jonathon W Sensinger
- Neural Engineering Center for Artificial Limbs, Rehabilitation Institute of Chicago, Chicago, IL 60611, USA.
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