ALLAN M. SCHRIER’s research while affiliated with Brown University and other places

The split-brain approach was utilized in 6 cats to test the degree of functional autonomy in the visual system. The central visual cortex of one hemisphere was isolated by the removal of most of the extravisual neocortex of the same hemisphere. Visual inflow was restricted to the isolated side in four cases by sectioning the crossed optic fibres at the chiasma and masking one eye and in two cases by section of the contralateral optic tract. The isolation produced severe deficits in visual performance, although all cases retained some ability to learn and to recall simple pattern discriminations. The results of two- and three-stage removals of the non-visual cortex, and of terminal section of the callosum, as well as histology of the lateral geniculate nucleus indicated that geniculo-striate damage was not the limiting factor. Removal of fronto-parietal cortex produced as much or more decrement in visual discrimination than did removal of temporal cortex.

Chiasm- and callosum-sectioned (split-brain) cats and controls were trained to displace the correct one of two different objects, using each forelimb half the time. During this discrimination training, vision was restricted to one eye, thus confining visual input and learning to a single hemisphere in the split-brain animals. It was found that either forelimb could be used about equally well by all the animals.