Research On Neural Mechanism Of Stereo Vision At Cat’s Primary Visual Cortex

Vision is a major means for human to percept external things. Human obtain information from the outside world largely by the visual system. Stereoscopic vision is a kind of advanced visual function, and is the foundation to perceive the three-dimensional scene. The primary visual cortex is an early visual cortex in visual information processing. Whether the primary visual cortex participate in the stereoscopic information processing and the mechanism of neural information processing are of great significance for more thorough and complete understanding of three-dimensional visual information processing mechanism.Although there are electrophysiology results which can prove there are disparity sensitive cells in the primary visual cortex, but how these cells are functional synthetic stereoscopic information is known.Aim at this problem, we research the mechanism of neural information processing in the primary visual cortex from the point of disparity column using the intrinsic optical imaging and the result is verified using single-unit physiology method. Our work mainly includes the following content:1. We proved the exist of the disparity column in the primary visual cortex of the cat using the optical imaging. It demonstrates that there are disparity sensitive neurons in the primary visual cortex.2. Disparity function column presents the obvious two categories: “nearly” cells which are sensitive to negative disparity and “far” disparity which are sensitive to positive disparity.We found that the contour and the center of positive disparity column or negative disparity columns are similar, but the contour and the center of positive disparity column and negative disparity columns are different.That demonstrates that near cells and far cells are in different region in the primary visual cortex, but the distribution of cells encoding the different size positive disparity or the different size negative disparity are similar.3. Under the same conditions,the function maps of the positive disparity and the negative disparity are complementary.That is to say,the region which is sensitive to positive disparity is not sensitive to negative disparity and the region which is sensitive to negative disparity is not sensitive to positive disparity.4. We found the reaction of the optical signal are the same with the averageresponse of the cells. In other words, the optical signal can represent the cells’ response.And we found that the proportion of the disparity sensitive cell are very small.In summary, the number of the disparity sensitive cells are small. Near cells and far cells are in different regions, but the cells encoding the positive or negative disparity of different size are in the same region. The primary visual cortex is the stereoscopic information processing’s early stage and may only process the information of “near” or“far” and not process the information of the size of the disparity.