Delayed alternation in adolescent and adult male and female rats.

The prefrontal cortex continues to develop throughout adolescence in several species, and our laboratory has demonstrated that during adolescence there is a decrease in neurons in the rat medial prefrontal cortex (mPFC). A PFC-dependent task, the delayed alternation task, was used in the present study to examine the function of the mPFC while it is still maturing in rats of both sexes. A deficit was found in adolescents when compared to adults during 15- and 60-s delays but not at other delays (5, 10, 30, and 90 s). Furthermore, adolescents committed more perseverative errors. No significant sex differences occurred at any delay for either age group; however, in the no delay training sessions, adolescent males reached criterion faster than females. These results indicate that performance on a mPFC-dependent task improves between adolescence and adulthood.