Distribution of tract deficits in schizophrenia.
BACKGROUND
Gray and white matter brain changes have been found in schizophrenia but the anatomical organizing process underlying these changes remains unknown. We aimed to identify gray and white matter volumetric changes in a group of patients with schizophrenia and to quantify the distribution of white matter tract changes using a novel approach which applied three complementary analyses to diffusion imaging data.


METHODS
21 patients with schizophrenia and 21 matched control subjects underwent brain magnetic resonance imaging. Gray and white matter volume differences were investigated using Voxel-based Morphometry (VBM). White matter diffusion changes were located using Tract Based Spatial Statistics (TBSS) and quantified within a standard atlas. Tracts where significant regional differences were located were examined using fiber tractography.


RESULTS
No significant differences in gray or white matter volumetry were found between the two groups. Using TBSS the schizophrenia group showed significantly lower fractional anisotropy (FA) compared to the controls in regions (false discovery rate <0.05) including the genu, body and splenium of the corpus callosum and the left anterior limb of the internal capsule (ALIC). Using fiber tractography, FA was significantly lower in schizophrenia in the corpus callosum genu (p = 0.003).


CONCLUSIONS
In schizophrenia, white matter diffusion deficits are prominent in medial frontal regions. These changes are consistent with the results of previous studies which have detected white matter changes in these areas. The pathology of schizophrenia may preferentially affect the prefrontal-thalamic white matter circuits traversing these regions.
Ian
I
Ellison-Wright
Pradeep J
PJ
Nathan
Edward T
ET
Bullmore
Rashid
R
Zaman
Robert B
RB
Dudas
Mark
M
Agius
Emilio
E
Fernandez-Egea
Ulrich
U
Müller
Chris M
CM
Dodds
Natalie J
NJ
Forde
Cathy
C
Scanlon
Alexander
A
Leemans
Colm
C
McDonald
Dara M
DM
Cannon
D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000473:pathology*; D012559:Schizophrenia / Q000473:pathology*; D066127:White Matter / Q000473:pathology*; D055815:Young Adult