STEREOTYPIES AND LOSS OF SOCIAL AFFILIATION AFTER EARLY HIPPOCAMPECTOMY IN PRIMATES

THE present study was aimed at determining whether early hippocampal d amage alters the development of normal social interactions. Results sh owed that, at 2 months of age, animals with neonatal hippocampal lesio ns presented minor disturbances in initiation of social interactions. These subtle changes in behavior were less evident at 6 months, althou gh at this age, the operated animals displayed more withdrawals in res ponse to an increase in aggressive responses from their unoperated pee rs. Finally, in adulthood, the amount of time spent by the operated mo nkeys in social contacts with their normal peers was markedly less tha n that in normal dyads. Only in adulthood did the operated animals exh ibit more locomotor stereotypies than normal controls. This finding su ggest that the hippocampal formation may directly or indirectly affect the maintenance of social bounds in primates.