CYTOCHROME-OXIDASE BLOBS IN CAT PRIMARY VISUAL-CORTEX

Cytochrome-oxidase blobs are central to two of the most influential id eas in contemporary visual neuroscience-cortical modularity and parall el processing pathways. In particular, the regular 2D array of cytochr ome-oxidase-rich blobs in primate visual cortex is arguably the most c ompelling evidence for cortical modularity and has been hypothesized t o mark a separate processing stream through the visual cortex. Althoug h previously a variety of mammals have been studied, blobs have only b een demonstrated in the visual cortex of primates, which has led to th e conclusion that blobs represent a primate-specific feature of visual cortical organization. Here we demonstrate the presence of cytochrome -oxidase blobs in a nonprimate species. Throughout the full tangential extent of layers II-III in cat visual cortex the cytochrome-oxidase s taining pattern is distinctly patchy, with the darkly stained blobs fo rming a regular 2D array. In addition, the blobs in cat visual cortex are functionally related to the underlying ocular dominance columns. T he presence of cytochrome-oxidase blobs in the cat clearly demonstrate s that they no longer can be considered a primate-specific feature of visual cortical organization.