Lithium Builds Gray Matter In Bipolar Brains, UCLA Study Shows
(April 16, 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."
Source: Medical News Today
Last updated: 04/07
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