New insights into prefrontal function in schizophrenia

Although many studies have reported diminished frontal lobe activation during cognitive tasks in schizophrenia, some studies have reported baseline frontal hyperactivity in acutely ill patients (Ebmeier et al, 1995). We employed fMRI to examine frontal activity in 8 first-episode patients and matched controls during the ™N-back∫ working memory task on two separate occasions. Patients were scanned for the first time while acutely psychotic and 6±8 weeks later after their symptoms remitted during antipsychotic treatment. During the acute state, patients exhibited significantly less activation in the 2-back condition relative to the 0-back condition, compared with healthy controls. Comparison with rest indicated that the reduced relative activation in patients was due to low activity during the 2-back condition together with abnormally high activation during the 0-back condition. After treatment, the frontal activation in the 2-back, relative to the 0-back condition, increased towards normal, due to normalization of the level of activity in the 0-back condition. However, the activity in the 2-back condition remained low. These findings suggest that the antipsychotic treatment is associated with reduction in aberrant frontal overactivity in the baseline state