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Fear Circuit Flares as Bipolar Youth Misread Faces
Compared to healthy children, those with bipolar disorder (BD) see greater hostility
in neutral faces and feel more fear when viewing them. They also have more activity
in emotion-regulating areas of the brain when they focus on emotional aspects
of neutral faces, researchers at NIH’s National Institute of Mental Health have
discovered. The new study provides some of the first clues to the underlying
workings of the episodes of mania and depression that disrupt friendships, school
and family life in up to 1% of children.
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The left amygdala and related structures (yellow
area where lines intersect) are part of an emotion-regulating brain circuit
where children with bipolar disorder showed greater activity when rating
their fear of neutral faces.
Source: NIH, National Institute of Mental Health |
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Studies using Magnetic Resonance Imaging (MRI) to see inside the brain have shown
that the amygdala, a fear hub in the brain, is smaller in children with BD than
in healthy age-mates. The data in adults isn’t as clear. The NIMH research team
reasoned that studying the disorder in children may yield insights into how BD
develops. Using functional MRI, they measured brain activity in 22 bipolar and
21 healthy youth while they rated neutral faces.
In the May 29, 2006, Proceedings of the National Academy of Sciences,
the researchers report that the left amygdala and its related structures were
activated more in youth with BD than in healthy youth when they were asked to
rate the emotional aspects of faces (hostility, subjects’ fearfulness), but not
when they rated a non-emotional feature such as nose width. Those with BD rated
themselves as more afraid, and rated the neutral faces as more hostile, compared
to healthy peers. The more they misinterpreted the faces as hostile, the more
their amygdalas flared. Such a face-processing deficit could help account for
the poor social skills, aggression and irritability that characterize this disorder
in children
“Our results suggest that children with bipolar disorder see emotion where other
people don’t,” explained senior author Dr. Ellen Leibenluft.
The results suggest that BD likely stems from impaired development of specific
brain circuits. The researchers will follow up with studies of children at genetic
risk for developing BD to see if they have the same amygdala over-activation.
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