ABSTRACT
Considering the prevalence and importance of major depressive disorder (MDD) and bipolar disorder (BPD), it is surprising that we have only very recently started to look carefully at the cerebral cellular architecture of these disorders. Structural imaging investigations of living subjects with mood disorders can point us in the direction of pathology. These imaging investigations have shown a variety of important changes. In the case of MDD, the subgenual anterior cingulate cortex, the hippocampus and the frontal cortex have been shown to be reduced in volume. In BPD, the hippocampal volume has also been shown to be reduced, and the amygdala may be increased in size. Functional imaging investigations have also provided clues to the neuronal circuits implicated in mood disorders and point to involvement of the corticolimbic and the corticostriatal networks.
