© J. S. Perrin, et al., PNAS Early Edition (March 2012)
Toning down internal chatter. Imaging scans show decreases in brain connectivity before (orange) and after (blue) treatment with ECT.
Since the 1930s, doctors have been jolting the brains of depressed patients with electricity to relieve their symptoms. The treatment, known as electroconvulsive therapy (ECT), works, but it can cause memory loss and confusion and lead to difficulty forming new memories. Today, physicians generally limit it to patients who are severely ill, including those at risk for suicide. Now, a brain-imaging study highlights the part of the brain most affected, perhaps pointing to safer, less-invasive ways to achieve the same results.
Depression may be caused by an overactive brain, says physicist and neuroscientist Christian Schwarzbauer of the University of Aberdeen in the United Kingdom. "There may be so much internal communication that the brain becomes preoccupied with itself, less able to process information coming in from the outside world," he says, noting that studies have found that people with depression have heightened connectivity among brain networks involved in paying attention, monitoring internal and external cues, remembering the past, and controlling emotions.
In a 2010 study, psychiatrist Yvette Sheline and colleagues at Washington University School of Medicine in St. Louis, Missouri, found that these overactive networks converged on a common point
in a region called the dorsal medial prefrontal cortex. This common point, dubbed the dorsal nexus, may "hot wire" the brain networks together in a way that leads to depression, the authors hypothesized.