LESIONS IN CAT LATERAL SUPRASYLVIAN CORTEX AFFECT THE PERCEPTION OF COMPLEX MOTION

We examined the effects of bilateral ibotenic acid lesions of cat late ral suprasylvian (LS) cortex on motion perception, Cats were tested on tasks requiring integration of local directional signals, precise jud gements of direction and extraction of structure from motion. All anim als showed permanent deficits in integrating local motion signals, The se deficits were most pronounced in the presence of directional noise and at larger spatial displacements. In addition, LS lesions produced a 2-fold loss in the accuracy of direction discrimination and large de ficits in the perception of structure-from motion. All of these losses were most severe during the first few weeks of testing following the lesion. These findings demonstrate that LS cortex plays an important r ole in the processing of stimuli requiring integration of motion infor mation and limits the spatial scale over which such integration can pr oceed. Partial improvements in performance with time and/or training m ay be indicative of post-operative plastic changes in neurons outside of LS cortex.