Increased neurophysiologic connectivity has been reported in people with major depressive disorder, according to data published in PLoS One.
Researchers at University of California, Los Angeles focused on malfunctions involving brain networks, taking into consideration the combination of multiple symptoms in people with depression rather than looking at individual brain areas.
They used weighted network analysis to examine resting state functional connectivity as measured by quantitative electroencephalographic (qEEG) coherence. They examined 121 unmedicated adults diagnosed with major depressive disorder (MDD) and 37 healthy controls.
Resting EEG, used to calculate qEEG coherence, was recorded in a quiet room with participants lying down; they were alerted to avoid drowsiness.
Participants with depression were found to have increased synchronization across all frequencies of electrical activity, compared with healthy controls, indicating dysfunction in many brain networks. The frontopolar and dorsolateral prefrontal cortex regions housed “hub nodes” — or, surface recording locations — that demonstrated the greatest degree of connectivity.
The study findings indicate a loss of selectivity in resting functional connectivity in people with MDD, according to the researchers.
Andrew Leuchter, MD, study author and professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, said the depressed brain maintains its ability to form functional connections but loses the ability to turn these connections off.
“This inability to control how the brain areas work together may help explain some of the symptoms in depression,” he said.
Disclosures: Funding for the study was provided by Eli Lilly and Company, Wyeth Pharmaceuticals (now owned by Pfizer) and Pfizer. The researchers report no relevant financial disclosures.