Fronto-temporal disconnectivity in schizotypal personality disorder: a diffusion tensor imaging study.
BACKGROUND
Using diffusion tensor imaging (DTI), we previously reported abnormalities in two critical white matter tracts in schizophrenia, the uncinate fasciculus (UF) and the cingulum bundle (CB), both related to fronto-temporal connectivity. Here, we investigate these two bundles in unmedicated subjects with schizotypal personality disorder (SPD).


METHODS
Fifteen male SPD subjects and 15 male control subjects were scanned with line-scan DTI. Fractional anisotropy (FA) and mean diffusivity (D(m)) were used to quantify water diffusion, and cross-sectional area was defined with a directional threshold method. Exploratory correlation analyses were evaluated with Spearman's rho, followed by post hoc hierarchical regression analyses.


RESULTS
We found bilaterally reduced FA in the UF of SPD subjects. For CB, there was no significant group difference for FA or D(m) measures. Additionally, in SPD, reduced FA in the right UF was correlated with clinical symptoms, including ideas of reference, suspiciousness, restricted affect, and social anxiety. In contrast, left UF area was correlated with measures of cognitive function, including general intelligence, verbal and visual memory, and executive performance.


CONCLUSIONS
These findings in SPD suggest altered fronto-temporal connectivity through the UF, similar to findings in schizophrenia, and intact neocortical-limbic connectivity through the CB, in marked contrast with what has been reported in schizophrenia.
Clinical Neuroscience Division, Department of Psychiatry, Veterans Affairs Boston Healthcare System, Brockton Division, Harvard Medical School, MA 02301, USA.
Motoaki
M
Nakamura
Robert W
RW
McCarley
Marek
M
Kubicki
Chandlee C
CC
Dickey
Margaret A
MA
Niznikiewicz
Martina M
MM
Voglmaier
Larry J
LJ
Seidman
Stephan E
SE
Maier
Carl-Fredrik
CF
Westin
Ron
R
Kikinis
Martha E
ME
Shenton
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging; D005625:Frontal Lobe / Q000378:metabolism* / Q000473:pathology; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D012569:Schizotypal Personality Disorder / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D013223:Statistics as Topic; D013702:Temporal Lobe / Q000378:metabolism* / Q000473:pathology