Abstract
RATIONALE: Stress experience during adolescence has been linked to the development of psychiatric disorders in adulthood, many of which are associated with impairments in prefrontal cortex function. OBJECTIVE: The current study was designed to determine the immediate and enduring effects of repeated social stress on a prefrontal cortex-dependent cognitive task. METHODS: Early adolescent (P28), mid-adolescent (P42), and adult (P70) rats were exposed to resident-intruder stress for 5 days and tested in an operant strategy-shifting task (OSST) during the following week or several weeks later during adulthood. Engagement of prefrontal cortical neurons during the task was assessed by expression of the immediate early gene, c-fos. RESULTS: Social stress during adolescence had no immediate effects on task performance, but impaired strategy-shifting in adulthood, whereas social stress that occurred during adulthood had no effect. The cognitive impairment produced by adolescent social stress was most pronounced in rats with a passive coping strategy. Notably, strategy-shifting performance was positively correlated with medial prefrontal cortical c-fos in adulthood but not in adolescence, suggesting that the task engages different brain regions in adolescents compared to adults. CONCLUSIONS: Adolescent social stress produces a protracted impairment in prefrontal cortex-mediated cognition that is related to coping strategy. This impairment may be selectively expressed in adulthood because prefrontal cortical activity is integral to task performance at this age but not during adolescence.