Role of forebrain commissures in integration of visual half fields by inferotemporal neurons

It has previously been shown that 60% of neurons in inferotemporal cortex of the macaque have receptive fields extending more than 10° into both visual half fields (1972). In this study, responses of inferotemporal neurons in the ipsilateral visual half field were eliminated by section of the corpus callosum plus anterior commissure and also by section of the splenium plus anterior commissure. By contrast, after section of only the corpus callosum, or only the splenium, or only the anterior commissure more than 25% of the neurons were still responsive in the ipsilateral half field. Thus, either the splenium or the anterior commissure alone can provide information to an inferotemporal neuron that enables it to integrate large regions of both visual half fields.