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SEARCHING FOR THE DARK SPRING OF DEPRESSION |
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Lori Altshuler, director of the UCLA Mood Disorders Research Program, has spent a good portion of her professional life working with patients who suffer from mood disorders, especially bipolar disorder. And she has come to understand that what medical researchers know about depression is far outweighed by what they do not know. |
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"Take diabetes, for instance," Altshuler explains. "We know that the main pathophysiology is in the pancreas and that it is related to not having enough insulin. But with bipolar and other psychiatric illnesses, we know the pathophysiology resides in the brain, but we have little more than a descriptive nature of the illness. We don't even have a clear understanding of where within the brain the chemical disturbances lie." Altshuler believes she can fill this void of knowledge using magnetic resonance imaging. Her strategy can be broken into three steps: the first is to locate any abnormal structures in the brain that are specific to the disorder. Step two is to identify the projections from the abnormal structure to other structures which might be related to the illness and could provide clues to understanding the relevant pathology. Finally, step three is to identify the specific neurotransmitters in the cells of the affected structures and determine how those neurotransmitters are distributed throughout the brain region. "Then," she says, "we can develop treatments that target those neurotransmitters specifically related to that part of the brain system." Over the past decade, studies have suggested that the most likely brain region involved in mood disorders (bipolar and unipolar) is within the temporal lobe, one of the four major lobes of the brain, located on either side of the brain below the cerebrum. Research in stroke victims and laboratory animals has further narrowed the possibilities to two structures in the temporal lobe that appear to be important in the regulation of mood and memory—the hippocampus, which is involved in learning and acquiring new memory, and the amygdala, which plays an important role in personality. "When the amygdala is removed in lab animals," observes Altshuler, "they have a complete personality change and usually become very tame and docile. When the amygdala is stimulated, animals may exhibit rage reactions." |
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