[Non-human primate behaviors as models for development of higher cognitive functions]

Non-human primate behaviors have a special value for the neurobiological study of the development of higher cognitive functions of humans, because of the near evolutional relation between two species. We surveyed results and futures of neurobiological studies of a retrieval task, a learning-set and a self-injurious behavior expressed by non-human primates. On the retrieval task that is related to the development of inhibitory control, it was revealed a hierarchical ordering of inhibitory control processes in which the distinct neuronal circuits were involved. On the learning-set that is related to the development of abstract thinking, neural circuits for the individual learning dramatically changed from an automatic process to a cognitive process depending on the learning-set formation. The self-injurious behavior is expressed during early normal development in humans, and no other animals but non-human primates express it without administration of drugs. For that behavior, probable change in interactions of multiple monoaminergic systems was suggested as its underlying causes. Further studies on development of higher cognitive functions using non-human primates could be required for understanding the nature of human cognition.