Cortically-Evoked Pinna Movement in the Cat

Summary 1. Pinna movements in the cat are evoked by electrical stimulation of two discrete cortical areas. One, in the ectosylvian gyrus (ES) evokes movements of both ears; the other in the anterior suprasylvian area (SS) is of lower threshold, and evokes movement of the contralateral ear alone. 2. Both areas are topographically situated in regions in which acoustic stimulation evokes electrical responses. 3. The 2 areas of sensory-motor overlap are considered to mediate 2 different cortical reflexes, the ES response of generalized alerting to unlocalized sound, and SS response one of oriented alerting to localized sound.