Centrifugal motion bias in the cat's lateral suprasylvian visual cortex is independent of early flow field exposure.

1. Neurones in the postero-medial part of the cat's lateral suprasylvian visual cortex (area PMLS) show an overall preference for centrifugal motion, suggesting that the PMLS may be specialized in the analysis of expanding optic flow fields associated with forward locomotion. 2. We examined whether the visual experience young kittens normally receive during forward locomotion guides the development of the centrifugal preference in the PMLS. 3. Seven kittens were reared in the dark and exposed to either expanding or contracting flow fields for at least 100 h during their 4th-11th weeks of life. Specific experience was achieved by exposing kittens either to flow field patterns generated on a screen or by actually moving them forward or backward in a carousel. 4. Our results show that although the development of directional selectivity in the PMLS requires visual experience, the centrifugal bias is independent of specific visual exposure. The preference for centrifugal motion among PMLS cells was just as evident in kittens exposed to contracting as in kittens exposed to expanding flow fields. 5. We conclude that the preference for centrifugal motion in the PMLS is not the result of anisotropic stimulation kittens receive during locomotion in early ontogeny, but is probably innately determined as a phylogenetic adaptation.