Effects of sombrevine on orientational tuning of visual cortex neurons in the cat

1990 ◽  
Vol 21 (6) ◽  
pp. 580-587
Author(s):  
N. A. Lazareva ◽  
R. V. Novikova ◽  
A. S. Tikhomirov ◽  
I. A. Shevelev ◽  
G. A. Sharaev
Keyword(s):  
Visual Cortex ◽  
Visual Cortex Neurons ◽  
Orientational Tuning

Dynamics of orientational tuning of feling visual cortex neurons under the effects of sombrevine

1990 ◽  
Vol 22 (1) ◽  
pp. 89-94
Author(s):  
I. A. Shevelev ◽  
N. A. Lazareva ◽  
R. V. Novikova ◽  
A. S. Tikhomirov ◽  
G. A. Sharaev
Keyword(s):  
Visual Cortex ◽  
Visual Cortex Neurons ◽  
Orientational Tuning

scholarly journals Functional Biases in Visual Cortex Neurons with Identified Projections to Higher Cortical Targets

2012 ◽  
Vol 22 (4) ◽  
pp. 269-277 ◽  
Author(s):  
Beata Jarosiewicz ◽  
James Schummers ◽  
Wasim Q. Malik ◽  
Emery N. Brown ◽  
Mriganka Sur
Keyword(s):  
Visual Cortex ◽  
Visual Cortex Neurons

Visual cortex neurons in monkey and cat: Effect of contrast on the spatial and temporal phase transfer functions

1995 ◽  
Vol 12 (6) ◽  
pp. 1191-1210 ◽  
Author(s):  
Duane G. Albrecht
Keyword(s):  
Visual Cortex ◽  
Transfer Function ◽  
Receptive Field ◽  
Transfer Functions ◽  
Phase Transfer ◽  
Sine Wave ◽  
Phase Advance ◽  
Systematic Effect ◽  
Temporal Phase ◽  
Visual Cortex Neurons

AbstractThe responses of simple cells (recorded from within the striate visual cortex) were measured as a function of the contrast and the frequency of sine-wave grating patterns in order to explore the effect of contrast on the spatial and temporal phase transfer functions and on the spatiotemporal receptive field. In general, as the contrast increased, the phase of the response advanced by approximately 45 ms (approximately one-quarter of a cycle for frequencies near 5 Hz), although the exact value varied from cell to cell. The dynamics of this phase-advance were similar to the dynamics of the amplitude: the amplitude and the phase increased in an accelerating fashion at lower contrasts and then saturated at higher contrasts. Further, the gain for both the amplitude and the phase appeared to be governed by the magnitude of the contrast rather than the magnitude of the response. For the spatial phase transfer function, variations in contrast had little or no systematic effect; all of the phase responses clustered around a single straight line, with a common slope and intercept. This implies that the phase-advance was not due to a change in the spatial properties of the neuron; it also implies that the phase-advance was not systematically related to the magnitude of the response amplitude. On the other hand, for the temporal phase transfer function, the phase responses fell on five straight lines, related to the five steps in contrast. As the contrast increased, the phase responses advanced such that both the slope and the intercept were affected. This implies that the phase-advance was a result of contrast-induced changes in both the response latency and the shape/symmetry of the temporal receptive field.

Receptive field expansion in adult visual cortex is linked to dynamic changes in strength of cortical connections

1995 ◽  
Vol 74 (2) ◽  
pp. 779-792 ◽  
Author(s):  
A. Das ◽  
C. D. Gilbert
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Visual Space ◽  
Final Analysis ◽  
Before And After ◽  
On Line ◽  
Adult Cats ◽  
Visual Cortex Neurons ◽  
Cortical Connection

1. Receptive field (RF) sizes of neurons in adult primary visual cortex are dynamic, expanding and contracting in response to alternate stimulation outside and within the RF over periods ranging from seconds to minutes. The substrate for this dynamic expansion was shown to lie in cortex, as opposed to subcortical parts of the visual pathway. The present study was designed to examine changes in cortical connection strengths that could underlie this observed plasticity by measuring the changes in cross-correlation histograms between pairs of primary visual cortex neurons that are induced to dynamically change their RF sizes. 2. Visually driven neural activity was recorded from single units in the superficial layers of primary visual cortex in adult cats, with two independent electrodes separated by 0.1–5 mm at their tips, and cross-correlated on-line. The neurons were then conditioned by stimulation with an “artificial scotoma,” a field of flashing random dots filling the region of visual space around a blank rectangle enclosing the RFs of the recorded neurons. The neuronal RFs were tested for expansion and their visually driven output again cross-correlated. After this, the neurons were stimulated vigorously through their RF centers to induce the field to collapse, and the visually driven output from the collapsed RFs was again cross-correlated. Cross-correlograms obtained before and after conditioning, and after RF collapse, were normalized by their flanks to control for changes in peak size due solely to fluctuations in spike rate. 3. A total of 37 pairs of neurons that showed distinct cross-correlogram peaks, and whose RF borders were clearly discernible both before and after conditioning, were used in the final analysis. Of these neuron pairs, conditioning led to a clear expansion of RF boundaries in 28 pairs, whereas in 9 pairs the RFs did not expand. RFs that did expand showed no significant shifts in their orientation preference, orientation selectivity, or ocularity. 4. When the RFs of a pair of neurons expanded with conditioning, the area of the associated flank-normalized cross-correlogram peaks also increased (by a factor ranging from 0.84 up to 3.5). Correlograms returned to their preconditioning values when RFs collapsed.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Optogenetic astrocyte activation modulates response selectivity of visual cortex neurons in vivo

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Gertrudis Perea ◽  
Aimei Yang ◽  
Edward S. Boyden ◽  
Mriganka Sur
Keyword(s):  
Visual Cortex ◽  
Astrocyte Activation ◽  
Visual Cortex Neurons

Responses of Rabbit Visual Cortex Neurons to Changes in the Orientation and Intensity of Visual Stimuli

2011 ◽  
Vol 41 (4) ◽  
pp. 416-425
Author(s):  
V. B. Polyanskii ◽  
D. E. Alymkulov ◽  
D. V. Evtikhin ◽  
E. N. Sokolov ◽  
B. V. Chernyshev
Keyword(s):  
Visual Cortex ◽  
Visual Stimuli ◽  
Visual Cortex Neurons ◽  
Rabbit Visual Cortex
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