by Amanda Gardner
23 August 2007
Scientists say one part of the brain is
responsible for initiating action, while a totally separate area is
in charge of not taking that action.
This newly identified region, involved in an aspect of self-control,
may change conceptions of human free will, the researchers said. It
could also explain the basis of impulsive as well as reluctant
behavior, they added.
"The central issue is quite simple.
If we want to do something, and we decide not to, how does that
brain wire that?" said Rajesh Miranda, associate
professor of neuroscience and experimental therapeutics at
Texas A&M Health Science Center College of Medicine.
"They showed the region in the brain
that can act as a gate to suppress a plan to do something," said
Miranda, who was not involved in the research.
"The big search in neuroscience is, are there general inhibiting
or specific inhibiting circuits?" added another outside expert,
Dr. John Hart, a spokesman for the American Academy of
Neurology and a behavioral neurologist and cognitive
neuroscientist at the University of Texas at Dallas.
"This is another piece of the
puzzle... but does it generalize beyond that task to all life
decisions? That has yet to be shown," he said.
This study and others like it are really
in their infancy, Miranda pointed out. That's important to remember,
since the findings could one day have legal and other implications.
"This kind of data could have
implications for legal definitions of 'diminished capacity,'"
he explained. "There's a potential for informing legal
definitions of mental illness and things like that."
The study, which was published in the
Aug. 22 issue of The Journal of Neuroscience, was conducted
by researchers from University College London, in the United
Kingdom, the Max Planck Institute in Leipzig, Germany, and Ghent
Using functional magnetic resonance imaging (fMRI),
the researchers studied the brain activity of participants in two
situations -- when they acted out as they had planned, or when they
decided not to follow their original intention.
Fifteen right-handed individuals (seven males and eight females,
average age 26) participated in a "go-no-go" exercise. They were
asked to press a button on a keyboard but first to indicate what
time they were going to perform this action. They were also asked to
choose instances in which they stopped before actually pressing the
When participants decided not to press the button, a specific area
of the frontal lobe region of the brain lit up. When participants
followed through, however, the area did not light up.
The executive-function frontal lobes, which have previously been
identified with inhibition, are part of what makes humans human,
"These areas are the most expanded
in humans as compared to animals," explained Dr. Kimford
Meador, spokesman for the American Academy of Neurology
and professor of neurology at the University of Florida,
"The frontal lobe is important for
initiation, for planning, personality, creativity."
"The frontal lobes distinguish us from lower-order creatures,"
added David Masur, director of neuropsychology in the
department of neurology at Montefiore Medical Center and
clinical professor of neurology at Albert Einstein College of
Medicine, both in New York City.
"We have larger frontal lobes, and
these are what really are responsible for much of what we define
as human behavior, social interaction, ability to plan,
organize, some language ability, abstract reasoning or
For now, the implications of the
research are esoteric but, down the line, who knows?
"Much of our society is based on the
concept of not only free will but also 'free won't,' the
inhibition of response," Masur explained.
"The difference between us as
intelligent ordered social creatures and the society that would
run amok is the ability to inhibit our responses, the ability to
take control if a situation calls for it, to stop acting in a
particular way... Maybe down the line somebody can develop a
drug or hormone or transmitter system that targets that
particular area of brain which strengthens the ability to negate
responses which are too impulsive."
"It's a fascinating mind-brain
question about where does our free will begin and end," added