The distribution of orientation of optimal stimuli for cells of striate cortex

The mechanism mediating the adaptation of cortical Area 17 oriented line detector cells is modeled. A novel form of environment and convergence property (which places a requirement on distribution of optimal stimuli) is utilized to show that classical concepts of synaptic efficiency loss due only to disuse are inadequate under the convergence property. A reasonable alternative is presented: a form of synaptic control which reduces synaptic efficiency at non-active synapses as a function of cell firing rate. We show that adequate solutions to our convergence property exist for members of this class. Simulations of this adequate mechanism indicate that under the very disjoint environment defined, small perturbations of the environment's distribution of stimuli may lead to large perturbations of the distribution of stimuli to which Area 17 cells are optimally responsive. A simulation indicates that this effect may be accentuated by a lateral interaction which causes like cell optimal stimuli to form near each other in cortex; and the effect may be reduced by a lateral interaction which causes like cell optimal stimuli to not form near each other. A form of neurophysiological experiment is suggested for verification.