Neuroscientists at The University of Texas Health Science Center at Houston (UTHealth) and the University of California, San Diego, say this new method may one day be useful for treating attention-deficit hyperactivity disorder (ADHD) and other severe disorders of self-control.
The study involved four volunteers with epilepsy who agreed to participate while being monitored for seizures at the Mischer Neuroscience Institute at Memorial Hermann-Texas Medical Center (TMC).
The four were asked to perform a simple behavioral task that required the braking or slowing of action — inhibition — in the brain.
For each patient, the researchers first identified the specific location for this brake in the prefrontal region of the brain. Next, a computer stimulated the prefrontal cortex exactly when braking was needed. This was done using electrodes implanted directly on the brain surface.
The stimulation with brief and imperceptible electrical charges led to increased braking, a form of enhanced self-control, the researchers reported.
“There is a circuit in the brain for inhibiting or braking responses,” said Nitin Tandon, M.D., the study’s senior author and associate professor in The Vivian L. Smith Department of Neurosurgery at the UTHealth Medical School. “We believe we are the first to show that we can enhance this braking system with brain stimulation.”
He noted that when the test was repeated stimulating a region outside the prefrontal cortex, there was no effect on behavior, showing the effect to be specific to the prefrontal braking system.
This was a double-blind study, meaning that participants and scientists did not know when or where the charges were being administered, he added.
The method of electrical stimulation was novel in that it apparently enhanced prefrontal function, whereas other human brain stimulation studies mostly disrupt normal brain activity, according to Tandon. This is the first published human study to enhance prefrontal lobe function using direct electrical stimulation, the researchers report.
Tandon has been working on self-control research with researchers at the University of California, San Diego, for five years.
“Our daily life is full of occasions when one must inhibit responses,” he said. “For example, one must stop speaking when it’s inappropriate to the social context and stop oneself from reaching for extra candy.”
The researchers are quick to point out that, while their results are promising, they do not yet point to the ability to improve self-control in general. In particular, this study does not show that direct electrical stimulation is a realistic option for treating self-control disorders such as obsessive-compulsive disorder, Tourette’s syndrome and borderline personality disorder.
Additionally, direct electrical stimulation requires an invasive surgical procedure, which is now used only for the localization and treatment of severe epilepsy, the researchers noted.
Their study appears in The Journal of Neuroscience.