Research On Hypercolumn Structure And Several Working Mechanism Of V2 Visual Cortex Of Bionic Brain

Based on the primate visual area V2, this article adopted methods of bionics, establishing visual area V2's hypercolumn structure and working mechanism model of Bionic Brain; then by making use of modern mathematics, extracted the mathematical structure of these structures and models, constructed their topological structure, grouping structure and category structure; At last, simulated them through the experiments.This paper firstly set up the V2 hypercolumn theory and model of bionic brain base on the hypercolumn theory of primary visual cortex and cell chain organization and modular organization configurations of primate visual area V2; secondly, established information transfer mode between sub-layers of V2 and between V2 and primary visual cortex and other extra cortexes; finally, built the V2 cortex work mechanism model, and put forward:1. Macroscopically, V2 visual cortex of bionic brain is divided into three sections, respectively correspond to dark thick stripes, thin stripes and pale stripes of primate, three modules respectively process visual elements of color, position and parallax.2. In V2 visual cortex, color cognition of the visual system mainly proceed perception of three primary colors and blend of two, here designed it get rainbow colors'cognition; moreover, it perceive combination of orientations 90 degrees different from each other; design of parallax information path mainly consider transfer of parallax information in the visual system model, according to ocular dominance and point to point messaging model, the visual system can determine the process of perception of depth within which eccentricity of which side of the cortex.Mathematical analysis and software simulation of designed various models, the conclusions were as follow:1. In a hypercolumn, the groups of color, orientation and parallax selective feature columns, with their receptive families of subset constitute a discrete topological space. Describe the receptive field of the feature columns with neighborhood, then each open set of the topological space can be represented as a neighborhood of each feature column of the open set, reveal overlapping relationship between receptive fields of adjacent columns. All the feature columns of a hypercolumn can be expressed as three topological spaces, respectively represent all feature columns of processing of color, orientation and parallax information as well as some of their functions. Topological spaces with continuous mapping between each other can all form categories.2. V2 cortex longitudinally sub-divided into six layers, of which neurons in layerⅢhave bipolar characteristics, in order to ensure the smooth conduct of perceptual grouping. At a certain moment, the states of the same types of neurons in the same sub-layer with the transmission of information between them form a regular surjective transformation group. The group as an object, all elements of this group as morphisms, they form a small category. Transition between states of a time and the next moment of pyramidal neurons forms a cyclic group, three symmetric group and permutation group. Groups of color, orientation and parallax selective neurons, together with the homomorphism between them, respectively constitute a category.3. Sub-layer neurons, together with the relative position between them constitute a category. Group of neurons of different sub-layers as objects, the serial equivalence relation, parallel relationship, homologous relationship a target relationship between them as morphisms, constitute the relationship categories, expressing transmission relationship of information between neuron clusters. Finally, expresses three information processing modules and the relative relationship between them of V2 with product categories and super functors.4. Receptive fields of V2 cortical neurons are constituted by two sub-regions and between them are no longer antagonistic. In the sub-layers process, color signal is coupled step by step, making the prospect of separating from the background; effect of lateral inhibition of the cortex makes the gradual separation of the boundary information, and form a complete profile step by step; relative parallax has a decisive role on the depth perception, and the relative size of the parallax determined mainly by the level of parallax; judgments of ocular dominance and visual areas play a key role in determining the activation of the binocular cells, they can decide which path the parallax information to access, and in which side of the brain to be processed.Based on the latest cognitive neuroscience results, this paper research on hypercolumn structure and working mechanism of V2 visual cortex of bionic brain revealed the arrangement of all types of feature column and processing rules of color, orientation and parallax information. This article also completed a further extraction of color and orientation information, got effective calculation of the parallax in the second stage of visual cortex of bionic brain. All of these researches form the foundation for more advanced studies of visual cortex.