SPATIOTEMPORAL FREQUENCY DOMAINS AND THEIR RELATION TO CYTOCHROME-OXIDASE STAINING IN CAT VISUAL-CORTEX

Spatial and temporal frequencies are important attributes of the visua l scene. It is a long-standing question whether these attributes are r epresented in a spatially organized way in cat primary visual cortex(1 -4). Using optical imaging of intrinsic signals(5-10), we show here th at grating stimuli of different spatial frequencies drifting at variou s speeds produce distinct activity patterns. Rather than observing a m ap of continuously changing spatial frequency preference across the co rtical surface, we found only two distinct sets of domains, one prefer ring low spatial frequency and high speed, and the other high spatial frequency and low speed. We compared the arrangement of these spatio-t emporal frequency domains with the cytochrome oxidase staining pattern , which, based on work in primate striate cortex, is thought to reflec t the partition of the visual cortex into different processing streams . We found that the cytochrome oxidase blobs in cat striate cortex coi ncide with domains engaged in the processing of low spatial and high t emporal frequency contents of the visual scene. Together with other re cent results(11), our data suggest that spatiotemporal frequency domai ns are a manifestation of parallel streams in cat visual cortex, with distinct patterns of thalamic inputs and extrastriate projections.