Functional anatomical correlates of antidepressant drug treatment assessed using PET measures of regional XXXX metabolism.

@entity308 @entity3831 @entity701 @entity4696 @entity413
Neurophysiological studies of major @entity308 performed using PET imaging have shown abnormalities of regional cerebral blood flow (CBF) and @entity413 metabolism in multiple prefrontal cortical and limbic structures that have been more generally implicated in emotional processing. The current study investigated the effects of antidepressant drug treatment in these regions using PET measures of @entity413 metabolism. Subjects with primary @entity4696 (n=27) were imaged while unmedicated and @entity308 , and, of these, 20 were rescanned following chronic antidepressant drug treatment. Regional metabolism was compared between unmedicated @entity308 and controls and between the pre- and post-treatment conditions in regions-of-interest (ROI) where metabolism or flow had previously been shown to be abnormal in unmedicated @entity308 . At baseline, the mean metabolism was increased in the left and right lateral orbital cortex/ventrolateral prefrontal cortex (PFC), left amygdala, and posterior cingulate cortex, and decreased in the subgenual ACC and dorsal medial/dorsal anterolateral PFC in the unmedicated @entity308 relative to controls, consistent with the results of previous studies. Following treatment, metabolism significantly decreased in the left amygdala and left subgenual ACC, and corresponding changes in the orbital and posterior cingulate cortices approached significance. The metabolic reduction in the amygdala and right subgenual ACC appeared largely limited to those subjects who both responded to treatment and remained well at 6 months follow-up, in whom the reduction in amygdala metabolism tightly correlated with the reduction in @entity3831 scores. The magnitude of the treatment-associated, metabolic change in the amygdala also correlated positively with the change in the stressed plasma @entity701 levels measured during scanning. These data converge with those from other PET studies to indicate that primary @entity4696 is associated with abnormal metabolism in limbic and paralimbic structures of the mesiotemporal and prefrontal cortices. Chronic antidepressant drug treatment reduces metabolism in the amygdala and ventral ACC in subjects showing a persistent, positive treatment response. In contrast, the persistence of the abnormal metabolic deficits in the dorsomedial/dorsal anterolateral PFC in @entity4696 during treatment may conceivably relate to the histopathological changes reported in these regions in post mortem studies of @entity4696 .
