A note on the characteristic response pattern in primary sensory projection cortex of the cat following a synchronous afferent volley

Electrical stimulation of the thalamic relay nuclei (ventralis posterior, medial geniculate, lateral geniculate) or their immediate prethalamic projection tracts, elicits in the appropriate sensory cortices a characteristic polyspike positive and negative wave. This response may also be elicited by direct cortical stimulation in striate cortex, but not in suprasylvian association cortex. The polyspike patterns are not elicited via the corpus callosum or other pathways. The cortical excitability cycle and the variation with stimulus intensity are described for these responses. Their mechanisms and nature are discussed.