Amblyopic deficits in the timing and strength of visual cortical responses to faces

Cortex ◽  
2013 ◽  
Vol 49 (4) ◽  
pp. 1013-1024 ◽  
Author(s):  
Éva M. Bankó ◽  
Judit Körtvélyes ◽  
János Németh ◽  
Béla Weiss ◽  
Zoltán Vidnyánszky
Keyword(s):  
Cortical Responses ◽  
Visual Cortical

Reticular facilitation of cat visual cortical responses is mediated by nicotinic and muscarinic cholinergic mechanisms

1993 ◽  
Vol 96 (1) ◽  
pp. 1-7 ◽  
Author(s):  
M. H. Lewandowski ◽  
C. M. Müller ◽  
W. Singer
Keyword(s):  
Cholinergic Mechanisms ◽  
Cortical Responses ◽  
Muscarinic Cholinergic ◽  
Visual Cortical

Context-Dependent Modulation of Early Visual Cortical Responses to Numerical and Nonnumerical Magnitudes

2021 ◽  
pp. 1-12
Author(s):  
Joonkoo Park ◽  
Sonia Godbole ◽  
Marty G. Woldorff ◽  
Elizabeth M. Brannon
Keyword(s):  
Visual Processing ◽  
Context Dependency ◽  
Numerical Magnitude ◽  
Continuous Variables ◽  
Processing Stream ◽  
Cortical Responses ◽  
Early Visual Cortex ◽  
Context Dependent ◽  
Visual Cortical ◽  
The Brain

Abstract Whether and how the brain encodes discrete numerical magnitude differently from continuous nonnumerical magnitude is hotly debated. In a previous set of studies, we orthogonally varied numerical (numerosity) and nonnumerical (size and spacing) dimensions of dot arrays and demonstrated a strong modulation of early visual evoked potentials (VEPs) by numerosity and not by nonnumerical dimensions. Although very little is known about the brain's response to systematic changes in continuous dimensions of a dot array, some authors intuit that the visual processing stream must be more sensitive to continuous magnitude information than to numerosity. To address this possibility, we measured VEPs of participants viewing dot arrays that changed exclusively in one nonnumerical magnitude dimension at a time (size or spacing) while holding numerosity constant and compared this to a condition where numerosity was changed while holding size and spacing constant. We found reliable but small neural sensitivity to exclusive changes in size and spacing; however, changing numerosity elicited a much more robust modulation of the VEPs. Together with previous work, these findings suggest that sensitivity to magnitude dimensions in early visual cortex is context dependent: The brain is moderately sensitive to changes in size and spacing when numerosity is held constant, but sensitivity to these continuous variables diminishes to a negligible level when numerosity is allowed to vary at the same time. Neurophysiological explanations for the encoding and context dependency of numerical and nonnumerical magnitudes are proposed within the framework of neuronal normalization.

Early visual cortical responses produced by checkerboard pattern stimulation

NeuroImage ◽  
2016 ◽  
Vol 134 ◽  
pp. 532-539 ◽  
Author(s):  
Yoshihito Shigihara ◽  
Hideyuki Hoshi ◽  
Semir Zeki
Keyword(s):  
Checkerboard Pattern ◽  
Cortical Responses ◽  
Pattern Stimulation ◽  
Visual Cortical

scholarly journals Suprachoroidal electrical stimulation: effects of stimulus pulse parameters on visual cortical responses

2013 ◽  
Vol 10 (5) ◽  
pp. 056011 ◽  
Author(s):  
Sam E John ◽  
Mohit N Shivdasani ◽  
Chris E Williams ◽  
John W Morley ◽  
Robert K Shepherd ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Stimulus Pulse ◽  
Pulse Parameters ◽  
Cortical Responses ◽  
Visual Cortical

Unilateral photoreceptor rescue can improve the ability of the opposite, untreated, eye to drive cortical cells in a retinal degeneration model

2005 ◽  
Vol 22 (1) ◽  
pp. 37-43 ◽  
Author(s):  
S.V. GIRMAN ◽  
R.D. LUND
Keyword(s):  
Cell Transplantation ◽  
Royal College ◽  
Visual Stimulation ◽  
Ocular Dominance ◽  
Photoreceptor Degeneration ◽  
Cortical Cells ◽  
Cortical Responses ◽  
Visual Cortical ◽  
Postsynaptic Mechanism ◽  
Stimulation Of

In the Royal College of Surgeons, rat photoreceptor degeneration occurs over the first several months of life, causing deterioration of visual cortical responsiveness seen as greater numbers of cells being nonresponsive to visual stimulation, poor tuning of those cells that do respond, and an overall tendency for domination by the contralateral visual input. If the progress of degeneration in one eye is slowed by intraretinal cell transplantation, cortical responses to stimulation of the remaining, untreated, eye are much stronger, better tuned and histograms of ocular dominance resemble more those in normal rats. This suggests that the rescued eye is able to enhance performance in the untreated eye by some form of postsynaptic mechanism.

scholarly journals Transferring and Generalizing Deep-Learning-based Neural Encoding Models across Subjects

2017 ◽  
Author(s):  
Haiguang Wen ◽  
Junxing Shi ◽  
Wei Chen ◽  
Zhongming Liu
Keyword(s):  
Deep Learning ◽  
Learning Models ◽  
Neural Encoding ◽  
Natural Vision ◽  
Cortical Responses ◽  
Single Subjects ◽  
Visual Cortical ◽  
The Relationship ◽  
Cortical Representations ◽  
The Brain

Recent studies have shown the value of using deep learning models for mapping and characterizing how the brain represents and organizes information for natural vision. However, modeling the relationship between deep learning models and the brain (or encoding models), requires measuring cortical responses to large and diverse sets of natural visual stimuli from single subjects. This requirement limits prior studies to few subjects, making it difficult to generalize findings across subjects or for a population. In this study, we developed new methods to transfer and generalize encoding models across subjects. To train encoding models specific to a subject, the models trained for other subjects were used as the prior models and were refined efficiently using Bayesian inference with a limited amount of data from the specific subject. To train encoding models for a population, the models were progressively trained and updated with incremental data from different subjects. For the proof of principle, we applied these methods to functional magnetic resonance imaging (fMRI) data from three subjects watching tens of hours of naturalistic videos, while deep residual neural network driven by image recognition was used to model the visual cortical processing. Results demonstrate that the methods developed herein provide an efficient and effective strategy to establish subject-specific or populationwide predictive models of cortical representations of high-dimensional and hierarchical visual features.

scholarly journals Voluntary temporal attention and MEG visual cortical responses

2020 ◽  
Vol 20 (11) ◽  
pp. 618
Author(s):  
Rachel Denison ◽  
Karen Tian ◽  
David Heeger ◽  
Marisa Carrasco
Keyword(s):  
Temporal Attention ◽  
Cortical Responses ◽  
Visual Cortical

scholarly journals Dark Rearing Promotes the Recovery of Visual Cortical Responses but Not the Morphology of Geniculocortical Axons in Amblyopic Cat

2021 ◽  
Vol 15 ◽  
Author(s):  
Takahiro Gotou ◽  
Katsuro Kameyama ◽  
Ayane Kobayashi ◽  
Kayoko Okamura ◽  
Takahiko Ando ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Cortical Neurons ◽  
Visual Pathway ◽  
Monocular Deprivation ◽  
Postnatal Life ◽  
Visual Neurons ◽  
Cortical Responses ◽  
Soma Size ◽  
Visual Cortical ◽  
Dark Rearing

Monocular deprivation (MD) of vision during early postnatal life induces amblyopia, and most neurons in the primary visual cortex lose their responses to the closed eye. Anatomically, the somata of neurons in the closed-eye recipient layer of the lateral geniculate nucleus (LGN) shrink and their axons projecting to the visual cortex retract. Although it has been difficult to restore visual acuity after maturation, recent studies in rodents and cats showed that a period of exposure to complete darkness could promote recovery from amblyopia induced by prior MD. However, in cats, which have an organization of central visual pathways similar to humans, the effect of dark rearing only improves monocular vision and does not restore binocular depth perception. To determine whether dark rearing can completely restore the visual pathway, we examined its effect on the three major concomitants of MD in individual visual neurons, eye preference of visual cortical neurons and soma size and axon morphology of LGN neurons. Dark rearing improved the recovery of visual cortical responses to the closed eye compared with the recovery under binocular conditions. However, geniculocortical axons serving the closed eye remained retracted after dark rearing, whereas reopening the closed eye restored the soma size of LGN neurons. These results indicate that dark rearing incompletely restores the visual pathway, and thus exerts a limited restorative effect on visual function.

Monocular deprivation reduces reliability of visual cortical responses to binocular disparity stimuli

2007 ◽  
Vol 26 (12) ◽  
pp. 3553-3563 ◽  
Author(s):  
Vasily Vorobyov ◽  
D. Samuel Schwarzkopf ◽  
Donald E. Mitchell ◽  
Frank Sengpiel
Keyword(s):  
Binocular Disparity ◽  
Monocular Deprivation ◽  
Cortical Responses ◽  
Visual Cortical

scholarly journals Human visual cortical responses to specular and matte motion flows

2015 ◽  
Vol 9 ◽  
Author(s):  
Tae-Eui Kam ◽  
Damien J. Mannion ◽  
Seong-Whan Lee ◽  
Katja Doerschner ◽  
Daniel J. Kersten
Keyword(s):  
Cortical Responses ◽  
Visual Cortical
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