Over on Science Now today, Los Angeles Times writer Geoffrey Mohan describes how neuroscientists here have "for the first time traced how three brain networks mediate the mind’s internal focus and its processing of stimuli from the outside world." Mohan goes on to explain:
By stimulating neurons with electromagnets, the researchers demonstrated how the brain’s executive and salience networks -- crucial for cognition and decision-making --- inhibit the default mode network, which centers on self-directed processes such as introspection, recall and rumination.
The study also turned up intriguing clues toward new therapies. One of the executive network nodes they stimulated was closely associated with inhibiting a specific area of the default mode that scientists believe is crucial to the antidepressant effects of magnetic stimulation and drug therapies. That could offer neurological clues to why magnetic stimulation appears to work – an effect that has remained somewhat mysterious.
“We’re already starting to think about how to use this for novel treatments,” [Amit Etkin, MD, PhD, lead author of the study] said. “If the default mode were abnormal in patients -- which we know to be true for a range of psychiatric disorders -- and you knew how to modulate it in the right way, which is what this study provides, then you would have a very important insight into how to potentially remediate these circuits for treatment of these disorders.”
The work appears online in Proceedings of the National Academy of Sciences.