The brakes of the Emotion
A recently discovered abnormality in an area of the brain that helps to control emotional reactions could lead to a new understanding of why persons develop depression and others affective disturbances.
By using PET, researchers found in patients with unipolar depression (only episodes of depression) and bipolar depression (interchange between depression and mania), an area of the pre-frontal cortex (subgenual region) with an abnormally diminished activity. This region is related with the emotional response, and it has widespread connections with others area of the brain responsible for the control of dopamine, noradrenaline, and serotonin, which have important role in the regulation of the mood.
On the other hand, in the same study, images obtained with the functional magnetic resonance (MRIf), has demonstrated a reduction of 48% in the gray matter in the same region, in persons with unipolar depression, and of 39% with bipolar depression.
According to Dreverts, "this same area could act as a set of brakes to emotional responses, helping us to maintain appropriate emotional moods. When this tissue doesn't work properly, this can be similar to a loss of emotional brakes, such that abnormal variations of mood might occur. Anti-depressant medications can compensate for this loss."
Nature, 386: (6627), 824-827, 1997