In Depression, Brain Structural Deficits May Contribute To Increased Functional Connections

In Depression, Brain Structural Deficits May Contribute To Increased Functional Connections

Major depressive tumult is associated with a dysregulation of brain regions including the prefrontal cortex and limbic system. The relationship between structural and functional abnormalities in these brain regions in depressed patients is more distant from clear. However, both types of changes are assumed to rest beneath the symptoms of this disorder.

This dearth of understanding prompted Dr. Bart de Kwaasteniet at the Academic Medical Center in Amsterdam and his colleagues to appliance a multimodal neuroimaging approach to more remote investigate this relationship.

The researchers, led the agency of Professor Damiaan Denys, recruited 18 patients by major depressive disorder and 24 invigorating individuals, all of whom underwent multiple neuroimaging scans. They specifically focused up the body the structural and functional connectivity between the subgenual anterior cingulate cortex (ACC) and the average temporal lobe, two regions that are related by a white matter tract called the uncinate fasciculus. These regions are known to exist involved in the regulation of mental agitation and memory.

de Kwaasteniet explained their findings: "We identified decreased structural integrity of the uncinate fasciculus connecting the medial temporal lobe and the subgenual ACC. Furthermore, we identified every increased functional connection between these regions in greater depression relative to controls. Importantly, we identified a negative correlation betwixt the integrity of this white body tract and the functional connection between the subgenual ACC and bilateral hippocampus in greater depression."

These results suggest that structural disturbances in the uncinate fasciculus give to abnormally high functional interactions in the midst of brain circuits associated with the symptoms of depravation. "This leads to the hypothesis that abnormalities in brain configuration lead to differences in connectivity between brain areas in depressive disorder," added de Kwaasteniet.

However, they furthermore hypothesized that the reverse may subsist true as well. In other tongues, that the increased functional connectivity amid these brain regions leads to structural changes in the brain's hoar matter fibers by means of some abnormally increased signal transduction. This theory is supported by recent studies in schizophrenia that suggest that circuit hyperactivity may be a predictor of subsequent cortical gradual wasting.

"This interesting study suggests that abnormalities in the structural connections betwixt brain regions, the white matter, are associated through abnormal activity within a brain field implicated in the symptoms of dejectedness. This observation raises an important act of asking about the implications of treating the tour functional abnormalities without fixing the underlying brain arrangement of parts," commented Dr. John Krystal, Editor of Biological Psychiatry. "Perhaps the structural abnormalities contribute to the risk for the return to a former state of depression among individuals whose brain boundary activity has responded to antidepressant medications."

More study will be necessary to test the theories generated from the tools and materials of this study.