scholarly journals Functional implications of orientation maps in primary visual cortex

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Erin Koch ◽  
Jianzhong Jin ◽  
Jose M. Alonso ◽  
Qasim Zaidi
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Orientation Maps ◽  
Functional Implications

scholarly journals Optimizing the Representation of Orientation Preference Maps in Visual Cortex

2015 ◽  
Vol 27 (1) ◽  
pp. 32-41
Author(s):  
Nicholas J. Hughes ◽  
Geoffrey J. Goodhill
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Color Space ◽  
Orientation Preference ◽  
Color Mapping ◽  
Functional Brain ◽  
Standard Representation ◽  
Visual Impression ◽  
Orientation Maps ◽  
True Structure

The colorful representation of orientation preference maps in primary visual cortex has become iconic. However, the standard representation is misleading because it uses a color mapping to indicate orientations based on the HSV (hue, saturation, value) color space, for which important perceptual features such as brightness, and not just hue, vary among orientations. This means that some orientations stand out more than others, conveying a distorted visual impression. This is particularly problematic for visualizing subtle biases caused by slight overrepresentation of some orientations due to, for example, stripe rearing. We show that displaying orientation maps with a color mapping based on a slightly modified version of the HCL (hue, chroma, lightness) color space, so that primarily only hue varies between orientations, leads to a more balanced visual impression. This makes it easier to perceive the true structure of this seminal example of functional brain architecture.

scholarly journals Lack of Patchy Horizontal Connectivity in Primary Visual Cortex of a Mammal without Orientation Maps

2006 ◽  
Vol 26 (29) ◽  
pp. 7680-7692 ◽  
Author(s):  
S. D. Van Hooser ◽  
J. A. Heimel ◽  
S. Chung ◽  
S. B. Nelson
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Orientation Maps

scholarly journals Mechanisms for Stable, Robust, and Adaptive Development of Orientation Maps in the Primary Visual Cortex

2013 ◽  
Vol 33 (40) ◽  
pp. 15747-15766 ◽  
Author(s):  
J.-L. R. Stevens ◽  
J. S. Law ◽  
J. Antolik ◽  
J. A. Bednar
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Orientation Maps ◽  
Adaptive Development

An Incremental Hebbian Learning Model of the Primary Visual Cortex with Lateral Plasticity and Real Input Patterns

1999 ◽  
Vol 54 (1-2) ◽  
pp. 128-140 ◽  
Author(s):  
Thomas Burger ◽  
Elmar W. Lang
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Cortical Neurons ◽  
Hebbian Learning ◽  
Ocular Dominance ◽  
Input Image ◽  
Natural Image ◽  
Mexican Hat ◽  
Orientation Maps ◽  
Lateral Coupling

We present a simplified binocular neural network model of the primary visual cortex with separate ON/OFF-pathways and modifiable afferent as well as intracortical synaptic couplings. Random as well as natural image stimuli drive the weight adaptation which follows Hebbian learning rules stabilized with constant norm and constant sum constraints. The simulations consider the development of orientation and ocular dominance maps under different conditions concerning stimulus patterns and lateral couplings. With random input patterns realistic orientation maps with ± 1/2-vortices mostly develop and plastic lateral couplings self-organize into mexican hat type structures on average. Using natural greyscale images as input patterns, realistic orientation maps develop as well and the lateral coupling profiles of the cortical neurons represent the two point correlations of the input image used

A Neural Network Model of Tilt Aftereffects

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 87-87
Author(s):  
J A Bednar ◽  
R Miikkulainen
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Indirect Effects ◽  
Lateral Interactions ◽  
Tilt Aftereffect ◽  
Feature Detectors ◽  
Large Numbers ◽  
Computational Support ◽  
Orientation Maps ◽  
Short Time

RF-LISSOM, a self-organising model of laterally connected orientation maps in the primary visual cortex, was used to study the psychological phenomenon known as the tilt aftereffect. The model allows observation of activation and connection patterns between large numbers of neurons simultaneously, making it possible to relate higher-level phenomena to low-level events, which is difficult to do experimentally. In RF-LISSOM, the same self-organising processes that are responsible for the development of the orientation map and its lateral connections are shown to result in tilt aftereffects over short time scales in the adult. The results give computational support for the idea that direct tilt aftereffects arise from adaptive lateral interactions between feature detectors, as has long been surmised. They also suggest that indirect effects could result from the conservation of synaptic resources during this process. The model thus provides a unified computational explanation of self-organisation and both direct and indirect tilt aftereffects in the primary visual cortex.

Comparative analysis of orientation maps in areas 17 and 18 of the cat primary visual cortex following adaptation

2014 ◽  
Vol 40 (3) ◽  
pp. 2554-2563 ◽  
Author(s):  
Sarah Cattan ◽  
Lyes Bachatene ◽  
Vishal Bharmauria ◽  
Jeyadarshan Jeyabalaratnam ◽  
Chantal Milleret ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Comparative Analysis ◽  
Primary Visual Cortex ◽  
Orientation Maps ◽  
Areas 17 And 18
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