Reduced anterior internal capsule and thalamic volumes in first-episode psychosis.
BACKGROUND
The thalamus is the gateway for sensory and motor information en route to the cortex. Information is processed via thalamocortical and corticothalamic pathways coursing through the internal capsules. In this study, we investigated the relationship between the anterior limb of the internal capsule, posterior limb of the internal capsule, and thalamus in first-episode psychosis (FEP).


METHODS
Twenty-nine FEP subjects (26 DSM-IV schizophrenia, 2 schizoaffective disorder, 1 psychosis not otherwise specified) and 22 healthy volunteers participated in this study. Anterior limb of the internal capsule (AIC), posterior limb of the internal capsule (PIC), and the thalamus volumes were manually determined from MRI scans.


RESULTS
FEP subjects had reduced AIC volumes (F(1,45)=6.18, p=0.017) and thalamic volumes (F(1,45)=8.00, p=0.007) compared to healthy volunteers. PIC volumes did not differ. Significant correlations between AIC volumes and thalamic volumes were observed in subjects with FEP, but not in healthy volunteers. Negative relationships between thalamic volumes and symptom severity were also observed.


CONCLUSIONS
The AIC and thalamic volumes were reduced in subjects with FEP compared to healthy volunteers. Abnormalities in thalamocortical and orticothalamic pathways may contribute to functional disruption of neural circuits in psychosis.
Lang
D J
DJ
Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada. dlang@interchange.ubc.ca
Khorram
B
B
Goghari
V M
VM
Kopala
L C
LC
Vandorpe
R A
RA
Rui
Q
Q
Smith
G N
GN
Honer
W G
WG
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D020772:Internal Capsule / Q000033:anatomy & histology / Q000473:pathology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D011618:Psychotic Disorders / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology*; D012559:Schizophrenia / Q000473:pathology / Q000503:physiopathology; D012720:Severity of Illness Index; D013788:Thalamus / Q000033:anatomy & histology / Q000473:pathology / Q000503:physiopathology