Altered Integrity of Perisylvian Language Pathways in Schizophrenia

Marco Catani, Michael C. Craig, Stephanie J. Forkel, Richard Kanaan, Marco Picchioni, Timothea Toulopoulou, Sukhwinder Shergill, Steve Williams, Declan G. Murphy, Philip McGuire
Biological Psychiatry. 2011-12-01; 70(12): 1143-1150
DOI: 10.1016/j.biopsych.2011.06.013

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BACKGROUND: Functional neuroimaging supports the hypothesis that auditory verbal
hallucinations (AVH) in schizophrenia result from altered functional connectivity
between perisylvian language regions, although the extent to which AVH are also
associated with an altered tract anatomy is less clear.
METHODS: Twenty-eight patients with schizophrenia subdivided into 17 subjects
with a history of AVH and 11 without a history of hallucinations and 59 age- and
IQ-matched healthy controls were recruited. The number of streamlines, fractional
anisotropy (FA), and mean diffusivity were measured along the length of the
arcuate fasciculus and its medial and lateral components.
RESULTS: Patients with schizophrenia had bilateral reduction of FA relative to
controls in the arcuate fasciculi (p < .001). Virtual dissection of the
subcomponents of the arcuate fasciculi revealed that these reductions were
specific to connections between posterior temporal and anterior regions in the
inferior frontal and parietal lobe. Also, compared with controls, the reduction
in FA of these tracts was highest, and bilateral, in patients with AVH, but in
patients without AVH, this reduction was reported only on the left.
CONCLUSIONS: These findings point toward a supraregional network model of AVH in
schizophrenia. They support the hypothesis that there may be selective
vulnerability of specific anatomical connections to posterior temporal regions in
schizophrenia and that extensive bilateral damage is associated with a greater
vulnerability to AVH. If confirmed by further studies, these findings may advance
our understanding of the anatomical factors that are protective against AVH and
predictive of a treatment response.

2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

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