The visual cortex appears to be responsible for perception of objects moving in three-dimensional space, and for compensation of image contrast over a wide range of a mammal's visual environment. We are interested in mechanisms among single neurons that accomplish these important functions. The approach is to test a neuron with a stimulus that includes randomized brief samples of motion to tease apart the effects of space and time. Differences in preferred velocity between the two eyes would suggest selectivity for motion in depth. These elemental motion responses are also reassembled to predict a wide array of responses that can be compared with responses of proposed models of the neuron's function.
Successful models provide great insight into the basis of neural mechanisms.
Similar measurements, after changing the contrast of the randomized stimulus, demonstrate the changes in gain and temporal properties that allow the visual system to operate efficiently over the wide range of contrasts that occur in the visual environment. Nonlinear directionally selective subunits in complex cells of cat striate cortex. Journal of Neurophysiology. Directionally selective complex cells and the computation of motion energy in cat visual cortex. For questions or suggestions concerning the content of these pages, contact the URMC Webmaster .