[Spatial frequency tuning characteristics of cat primary visual cortex at different topological locations by optical...

Using optical imaging based on intrinsic signals, we studied spatial frequency tuning characteristics of cat primary visual cortex at different visual topological locations. We found that the areas representing the peripheral visual field had null or very weak responses to high spatial frequency grating stimuli, whereas the areas representing the central visual field responded to the stimuli of a wide range of spatial frequencies with greater responses to high spatial frequencies. The more centered the corresponding visual field of the cortical area, the higher the cutoff spatial frequency. The spatial frequency tuning curves also tended to have a smooth shift along the cortical surface. The results above demonstrate that spatial frequency tuning characteristics of the primary visual cortex change according to different visual topological locations of the cortical areas, in addition to the existence of spatial frequency columns. It is suggested that the distribution of spatial frequency columns may be related to visual topology.