The effect of species-specific vocalization on the discharge of auditory cortical cells in the awake squirrel monkey (Saimiri sciureus)

Summary Action potentials of single auditory cortical neurons of the squirrel monkey were recorded in a chronic, unanesthetized preparation. The responsiveness of units was tested with various types of simple and complex acoustic stimuli in a free field situation. As simple auditory stimuli, bursts of pure tones, clicks, and white noise were utilized. Species-specific vocalizations served as complex, biologically significant stimuli.The data are based on 48 neurons which showed a discrete response to speciesspecific vocalizations. In 63% the response to calls could be predicted from the units' responses to simple stimuli. Thirty-seven percent of the neurons were classified as unpredictable with respect to their responsiveness to vocalizations. The response of most units was restricted to call stimuli which showed similarities in their frequency-time characteristics. About 7% of the 116 units responding to calls were classified as selective responders because they were not excited by any other stimulus tested. It was not possible to single out the acoustic features to which these units responded.Peter Winter died in an skiing accident in March, 1972.