Adolescent rats show cognitive rigidity in a test of attentional set shifting.

As neuropsychiatric disorders such as schizophrenia, attention deficit disorder, and mood disorders all impact executive function and are likely to be diagnosed prior to adulthood, it is important to understand the normal ontogeny of executive function. Previous behavioral research has shown that adolescents' executive function is different than that of adults. In the present study, we use a previously validated cognitive test, the intradimensional/extradimensional (ID/ED) set-shifting task, to assess attentional set shifting and reversal learning in adolescent and adult, male, Long-Evans rats. These data suggest that adolescent rats are more cognitively rigid than adult rats and have impairments in the shifting, but not formation, of an attentional set. Adolescent rats are also more susceptible to distraction than adult rats when an irrelevant stimulus dimension is introduced as part of a complex stimulus. Moreover, we find that attentional set shifting becomes adult-like at an earlier age than reversal learning. As these functions are mediated by distinct prefrontal subregions, that is, the prelimbic and orbitofrontal cortices, respectively, we hypothesize that prefrontal cortical subregions show slightly different developmental trajectories.