Background
Individuals with generalized social anxiety disorder (GSAD) exhibit exaggerated amygdala
reactivity to aversive social stimuli. These findings could be explained by microstructural
abnormalities in white matter (WM) tracts that connect the amygdala and prefrontal
cortex, which is known to modulate the amygdala's response to threat. The goal of
this study was to investigate brain frontal WM abnormalities using diffusion tensor
imaging (DTI) in patients with social anxiety disorder.
Methods
A Turboprop DTI sequence was used to acquire diffusion tensor images in 30 patients
with GSAD and 30 matched healthy control subjects. Fractional anisotropy, an index
of axonal organization, within WM was quantified in individual subjects, and an automated
voxel-based, whole-brain method was used to analyze group differences.
Results
Compared with healthy control subjects, patients had significantly lower fractional
anisotropy localized to the right uncinate fasciculus WM near the orbitofrontal cortex.
There were no areas of higher fractional anisotropy in patients than controls.
Conclusions
These findings point to an abnormality in the uncinate fasciculus, the major WM tract
connecting the frontal cortex to the amygdala and other limbic temporal regions, in
GSAD, which could underlie the aberrant amygdala-prefrontal interactions resulting
in dysfunctional social threat processing in this illness.
Key Words
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Article Info
Publication History
Published online: April 13, 2009
Accepted:
February 24,
2009
Received in revised form:
February 5,
2009
Received:
September 17,
2008
Identification
Copyright
Published by Elsevier Inc.
