Movements of the jaw and orofacial regions evoked by stimulation of two different cortical areas in cats.

Functional properties of the jaw and orofacial motor areas in the cerebral cortex of the lightly anesthetized cat were studied on the basis of the motor effects produced by intracortical microstimulation (ICMS). Jaw and orofacial motor effects were evoked by ICMS (less than 30 microA) delivered to the anterior parts of the coronal and lateral sigmoid gyri (C, coronal area), and the anterior part of the orbital gyrus (O, orbital area). Different patterns of movements in the jaw and orofacial regions were evoked from these two areas. In C one or, at most, two types of simple movement were produced by ICMS to one location, while in O more coordinated movements than those in C were produced. Cytoarchitectonically the jaw and orofacial motor areas were restricted to areas 3a, 4 gamma, and 6a beta in C, and to area 43 in O.