The findings that working memory impairments are a core feature of
schizophrenia, that they appear to be present and progressive during
childhood–adolescence, and that they are associated with abnormalities
in activation of the DLPFC raise two critical questions: (i) what
abnormalities in DLPFC circuitry are present in individuals diagnosed
with schizophrenia?; (ii) which of these abnormalities are likely to
reflect alterations in the normal developmental trajectories of DLPFC
circuitry? These questions are addressed in the following two sections.