Auditory ERPs to Stimulus Deviance in an Awake Chimpanzee (Pan troglodytes): Towards Hominid Cognitive Neurosciences
Ari Ueno, Satoshi Hirata, Kohki Fuwa, Keiko Sugama, Kiyo Kusunoki, Goh Matsuda, Hirokata Fukushima, Kazuo Hiraki, Masaki Tomonaga, Toshikazu Hasegawa
For decades, the chimpanzee, phylogenetically closest to humans, has been analyzed intensively in comparative
cognitive studies. Other than the accumulation of behavioral data, the neural basis for cognitive processing in the chimpanzee
remains to be clarified. To increase our knowledge on the evolutionary and neural basis of human cognition, comparative
neurophysiological studies exploring endogenous neural activities in the awake state are needed. However, to date, such
studies have rarely been reported in non-human hominid species, due to the practical difficulties in conducting non-invasive
measurements on awake individuals.
Methodology/Principal Findings. We measured auditory event-related potentials (ERPs) of a fully awake chimpanzee, with reference to a well-documented component of human studies, namely mismatch negativity (MMN). In response to infrequent, deviant tones that were delivered in a uniform sound stream, a comparable ERP component could be detected as negative deflections in early latencies.
Conclusions/Significance. The present study reports the MMN-like component in a chimpanzee for the first time. In human studies, various ERP components, including MMN, are well-documented indicators of cognitive and neural processing. The results of the present study validate the use of noninvasive ERP measurements for studies on cognitive and neural processing in chimpanzees, and open the way for future studies comparing endogenous neural activities between humans and chimpanzees. This signifies an essential step in hominid cognitive neurosciences.