Harvard Gazette: Like musical sounds, different states of mind are defined by distinct, characteristic waveforms, recognizable frequencies and rhythms in the brain’s electrical field. When the brain is alert and performing complex computations, the cerebral cortex — the wrinkled outer surface of the brain — thrums with cortical band oscillations in the gamma wavelength. In some neurological disorders like schizophrenia, however, these waves are out of tune and the rhythm is out of sync.

New research led by Harvard Medical School (HMS) scientists at the VA Boston Healthcare System (VABHS) has identified a specific class of neurons — basal forebrain GABA parvalbumin neurons, or PV neurons — that trigger these waves, acting as neurological conductors that trigger the cortex to hum rhythmically and in tune. (GABA is gamma-amniobutyric acid, a major neurotransmitter in the brain.)

The results appear this week in the journal Proceedings of the National Academy of Sciences.

“This is a move toward a unified theory of consciousness control,” said co-senior author Robert McCarley, HMS professor of psychiatry and head of the Department of Psychiatry at VA Boston Healthcare. “We’ve known that the basal forebrain is important in turning consciousness on and off in sleep and wake, but now we’ve found that these specific cells also play a key role in triggering the synchronized rhythms that characterize conscious thought, perception, and problem-solving.” [Continue reading…]