The crudest form of electrical intervention is electroconvulsive therapy, or E.C.T., which sends a seizure-inducing current through the brain, providing at least temporary relief to some people with severe depression. Doctors have used E.C.T. for nearly a century, although the treatment remains controversial for many patients. Metaphorically speaking, E.C.T. is akin to halting the orchestra’s performance and sending the musicians , from oboe to timpani, home to get some rest and come back tomorrow refreshed.
A more targeted form of electrical therapy, called deep brain stimulation, or D.B.S., has been used to manage conditions such as Parkinson’s disease and epilepsy. In D.B.S., an electrode is threaded into a specific area of the brain that is being disruptive; stimulating it, paradoxically, knocks out activity in that specific region.
If a particularly strong section is off-key, “it can affect the entire system, and the whole orchestra sounds off,” said Dr. Helen Mayberg, director of the Center for Advanced Circuit Therapeutics at Mt. Sinai’s medical school; she has developed D.B.S. strategies for severe depression. “You can think of it as firing everyone in that section” — sending the percussion home permanently — Dr. Mayberg said. “Precision is absolutely critical.”.
The recent brain-stimulation studies employ a technique distinct from either E.C.T. or D.B.S., but which still can be understood in terms of an orchestra. In one of the studies, scientists at Boston University found that they could improve working memory in older adults by optimizing what’s called rhythmic “coupling” between frontal and temporal cortex areas in a person’s brain.
In the brain, the activities of distant regions coordinate by means of low-frequency theta waves. The researchers used electric stimulation, delivered through a skullcap, to amplify these waves, enhancing coordination between the two brain regions and, in older adults, improving working memory.
“We think what we’re doing is essentially synchronizing these two separated areas,” said Robert M.G. Reinhart, a neuroscientist at Boston University and one of the authors of that study. In effect, the stimulation acts as an orchestra conductor, listening, synthesizing and leading.
In another recent study, a team of brain scientists found that they could blunt or reverse symptoms of fatigue, poor concentration and mental fogginess in a woman who had suffered a severe brain injury in a car accident 18 years earlier. They did so by providing steady current, during waking hours, through two electrodes implanted on either side of the thalamus, a deep brain region often described as a central switching center of the brain. Metaphorically, they turned up the volume — or, perhaps, they had the conductor clap her hands and fix a hard stare on the musicians.