VOCAL PERCEPTION - BRAIN EVENT-RELATED POTENTIALS IN A CHIMPANZEE

We describe the first brain event-related potential (ERP) study of cog nitive processes in the chimpanzee. In an extension of our studies on the ontogeny of vocal perception, ERP measures were obtained during th e presentation of simple nonsignal stimuli as well as conspecific and human vocalizations. We initially confirmed findings from humans and m onkeys of the appearance of a long-latency positivity in the ERP wavef orm to a rare stimulus in an oddball paradigm. This ERP component is r eminiscent of the P3a reported in humans under similar (passive) exper imental conditions. We further demonstrated that both conspecific and human vocal stimuli having affective significance also enhanced late p ositive components of the ERP. These late positive components displaye d a predominant fronto-central distribution, with a maxima at Cz. Addi tionally, responses to adaptively significant vocal stimuli showed a r ight hemisphere laterality, whereas no significant laterality was obse rved with the rare stimulus in the oddball paradigm. Results document the feasibility of ERP measures in chimpanzees and their potential uti lity in the study of the ontogeny and phylogeny of vocal perception. ( C) 1993 John Wiley & Sons, Inc.