Research
by UTHealth neurosurgeon Nitin Tandon, M.D., and his colleagues is furthering
the understanding of how the brain brakes impulsive behavior.
|
Dec.
13, 2013 — If you have ever said or done the wrong thing at the wrong time, you
should read this. Neuroscientists at The University of Texas Health Science
Center at Houston (UTHealth) and the University of California, San Diego, have
successfully demonstrated a technique to enhance a form of self-control through
a novel form of brain stimulation. Study participants were asked to perform a
simple behavioral task that required the braking/slowing of action --
inhibition -- in the brain. In each participant, the researchers first
identified the specific location for this brake in the prefrontal region of the
brain. Next, they increased activity in this brain region using stimulation
with brief and imperceptible electrical charges. This led to increased braking
-- a form of enhanced self-control.
This
proof-of-principle study appears in the Dec. 11 issue of The Journal of
Neuroscience and its methods may one day be useful for treating attention
deficit hyperactivity disorder (ADHD), Tourette's syndrome and other severe
disorders of self-control.
"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."
A
computer stimulated the prefrontal cortex exactly when braking was needed. This
was done using electrodes implanted directly on the brain surface. When the
test was repeated with stimulation of a brain 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.
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. This is the first published human study to
enhance prefrontal lobe function using direct electrical stimulation, the
researchers report.
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). Stimulation enhanced braking in all four
participants.
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. For example, one must stop speaking
when it's inappropriate to the social context and stop oneself from reaching
for extra candy," said Tandon, who is a neurosurgeon with the Mischer
Neuroscience Institute at Memorial Hermann-TMC.
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 human self-control disorders such as
obsessive-compulsive disorder, Tourette's syndrome and borderline personality
disorder. Notably, direct electrical stimulation requires an invasive surgical
procedure, which is now used only for the localization and treatment of severe
epilepsy.
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