UCLA: Lithium Builds Gray Matter in Bipolar Brains, UCLA Study Shows
Novel brain imaging technique suggests how lithium works as a therapeutic
LOS ANGELES, April 12, 2007--Neuroscientists at UCLA have shown
that lithium, long the standard treatment for bipolar disorder,
increases the amount of gray matter in the brains of patients with
the illness.
The research is featured in the July issue of the journal
Biological Psychiatry and is currently available online.
Carrie Bearden, a clinical neuropsychologist and assistant
professor of psychiatry at UCLA, and Paul Thompson, associate
professor of neurology at the UCLA Laboratory of Neuro Imaging,
used a novel method of three-dimensional magnetic resonance imaging
(MRI) to map the entire surface of the brain in people diagnosed
with bipolar disorder.
When the researchers compared the brains of bipolar patients on
lithium with those of people without the disorder and those of
bipolar patients not on lithium, they found that the volume of gray
matter in the brains of those on lithium was as much as 15 percent
higher in areas that are critical for attention and controlling
emotions.
The neurobiological underpinnings of bipolar disorder — an
illness marked by a roller coaster of emotions between mania and
depression — are not well understood. Nor is it understood
how lithium works in controlling these severe mood swings, even
though it has been the standard treatment for some 50 years. These
new findings suggest that lithium may work by increasing the amount
of gray matter in particular brain areas, which in turn suggests
that existing gray matter in these regions of bipolar brains may be
underused or dysfunctional.
This is the first time researchers were able to look at specific
regions of the brain that may be affected by lithium treatment in
living human subjects, said Bearden.
“We used a novel method for brain imaging analysis that is
exquisitely sensitive to subtle differences in brain
structure,” she said. “This type of imaging has not
been used before to study bipolar patients. We also revealed how
commonly used medications affect the bipolar brain.”
Although other studies have measured increases in the overall
volume of the brain, Bearden said, this imaging method allowed the
researchers to see exactly which brain regions were affected by
lithium.
“Bipolar patients who were taking lithium had a striking
increase in gray matter in the cingulate and paralimbic regions of
the brain,” she said. “These regions regulate
attention, motivation and emotion, which are profoundly affected in
bipolar illness.”
While conventional MRI studies have measured brain volume in total,
this new image analysis allows researchers to examine differences
in cortical anatomy at a much greater spatial resolution.
In this study, Bearden and colleagues at UCLA used computer
analysis to analyze brain scans collected by collaborators at the
University of Pittsburgh in order to determine whether bipolar
patients showed changes in brain tissue and, if so, whether those
changes were influenced by lithium treatment. Specifically, they
employed high-resolution MRI and cortical pattern-matching methods
to map gray matter differences in 28 adults with bipolar disorder
— 70 percent of whom were lithium-treated — and 28
healthy control subjects. Detailed spatial analyses of gray matter
distribution were conducted by measuring local volumes of gray
matter at thousands of locations in the brain.
While the brains of lithium-treated bipolar patients did not differ
from those of the control subjects in total white-matter volume,
their overall gray-matter volume was significantly higher,
sometimes by as much as 15 percent.
Unfortunately, said Bearden, there is no evidence that the increase
in gray matter persists if lithium treatment is discontinued.
“But it does suggest that lithium can have dramatic effects
on gray matter in the brain,” she said. “This may be an
important clue as to how and why it works.”
Graphics from the study are available online at:
www.loni.ucla.edu/~khayashi/Texas/BIPOLAR/newCOVER_8x10_bipolar.tif
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Mark Wheeler
Senior Media Relations Rep
UCLA Health Sciences Media Relations
Voice: (310) 794-2265 or (310) 794-0777
CELL: (310) 562-8843
FAX: (310) 794-2259
Posted: April 2007
