RESPONSES ELICITED FROM ORBITAL CORTEX OF CATS: OVERT ACTIVITY AND RELATED PATHWAYS.

Abstract

Electrical stimulation of the cortex adjacent to the presylvian sulcus in unanesthetized cats through implanted electrodes yields inhibition of walking but not of tone or other activities. Alerting appears to be the common denominator for elicited responses which include alteration in respiration, sniffing, licking, chewing, staring, skin hypersenstivity, alerting, tail wagging, and the like. Results suggest that this cortical area functions in part in claboration of alerting and/or protective behavior initiated by a wide variety of sensory modalities (more than the "oral senses"). Olfactory bulb stimulation did not yield the alerting pattern. Pathways were traced by evoked potentials from the fixed points of the known "function" described above. Localized activity initiated through different fixed electrodes was recorded in the internal capsule, basis pedunculi, pyramid, substantia nigra, reticular formation of mesencephalon and medulla, caudate nucleus, thalamus except anterior nucleus, hypothalamus except mamillary bodies, anterior sylvian and ectosylvian gyri, cingulate gyrus, and the cerebellum. Projection via internal capsule to the reticular formation seems to be the most likely route for inhibition.