ABSTRACT
This chapter focuses on recent work that has utilized in vivo brain imaging
to understand the mechanisms involved in bipolar disorder. Structural
magnetic resonance imaging (MRI) and neurochemical studies with mag-
netic resonance spectroscopy (MRS) have identified changes in prefrontal
cortex regions, which are highly interconnected with limbic portions of the
brain, including medial temporal lobe regions and the striatum.1 Some of
these regions or the connections between them may be impaired and possi-
bly result in the mood dysregulation that we see in patients who have mood
disorders.2,3
One of the regions of interest is the anterior cingulate, which is thought
to be involved in the pathophysiology of mood disorders. In some of our
prior work we measured the cingulate gyrus, subdivided into specific
regions, and found a reduction in the grey matter content in the left anteri-
or cingulate in untreated bipolar patients compared with healthy controls.4
Reduction in anterior cingulate grey matter volumes4,5 and density6,7 is a
consistently reported finding in recent studies. Cingulate findings are also
