Lesions of extrastriate cortex and consequences for visual guidance during locomotion.
One of the functions of the putative motion pathway in visual cortex may be visual guidance during locomotion. Using cats, we have investigated the role of the first area in this pathway, the lateral suprasylvian visual area (LS, often considered analogous to the primate area MT). Visual function during locomotion was tested by looking at the accuracy of foot placement as cats walked down a cluttered alley. Cats were tested before and after LS was lesioned bilaterally using ibotenic acid. In all four cats tested, partial lesions of LS caused a significant deterioration in the accuracy of foot placement, though cats showed no deficit in acuity or in pattern discrimination. To determine whether the observed deficit was specific to the motion pathway, in two additional cats lesions were made in the central field representation in area 19, which lies adjacent to LS but belongs to the putative object recognition pathway. Surprisingly, both cats showed significant improvements in their accuracy of foot placement during locomotion. The reason for this improvement was unclear.
Sherk
Helen
H
Department of Biological Structure, Box 35-7420, University of Washington, Seattle, WA 98195, USA. has@u.washington.edu
Fowler
Garth A
GA
D000818:Animals; D002415:Cats; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity; D005528:Foot / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D007051:Ibotenic Acid / Q000633:toxicity; D008124:Locomotion / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D015349:Vision, Monocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology; D014793:Visual Cortex / Q000293:injuries / Q000502:physiology*
D018690:Excitatory Amino Acid Agonists; D007051:Ibotenic Acid