Structural brain correlates of sensorimotor gating in antipsychotic-naive men with first-episode schizophrenia.
BACKGROUND
Prepulse inhibition (PPI) of the startle reflex is modulated by a complex neural network. Prepulse inhibition impairments are found at all stages of schizophrenia. Previous magnetic resonance imaging (MRI) studies suggest that brain correlates of PPI differ between patients with schizophrenia and healthy controls; however, these studies included only patients with chronic illness and medicated patients. Our aim was to examine the structural brain correlates of PPI in antipsychotic-naive patients with first-episode schizophrenia.


METHODS
We performed acoustic PPI assessment and structural MRI (1.5 and 3 T) in men with first-episode schizophrenia and age-matched controls. Voxel-based morphometry was used to investigate the association between PPI and grey matter volumes.


RESULTS
We included 27 patients and 38 controls in the study. Patients had lower PPI than controls. The brain areas in which PPI and grey matter volume correlated did not differ between the groups. Independent of group, PPI was significantly and positively associated with regional grey matter volume in the right superior parietal cortex. Prepulse inhibition and grey matter volume associations were also observed in the left rostral dorsal premotor cortex, the right presupplementary motor area and the anterior medial superior frontal gyrus bilaterally. Follow-up analyses suggested that the rostral dorsal premotor cortex and presupplementary motor area correlations were driven predominantly by the controls.


CONCLUSIONS
We used 2 different MRI scanners, which might have limited our ability to find subcortical associations since interscanner consistency is low for subcortical regions.


CONCLUSIONS
The superior parietal cortex seems to be involved in the regulation of PPI in controls and antipsychotic-naive men with first-episode schizophrenia. Our observation that PPI deficits in schizophrenia may be related to the rostral dorsal premotor cortex and presupplementary motor area, brain areas involved in maintaining relevant sensory information and voluntary inhibition, warrants further study.
Center for Neuropsychiatric Schizophrenia Research, Copenhagen University Hospital, Glostrup, Denmark. tbh@cnsr.dk
Trine Bjørg
TB
Hammer
Bob
B
Oranje
Arnold
A
Skimminge
Bodil
B
Aggernæs
Bjørn H
BH
Ebdrup
Birte
B
Glenthøj
William
W
Baaré
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D013216:Reflex, Startle / Q000502:physiology*; D012559:Schizophrenia / Q000503:physiopathology*; D055139:Sensory Gating / Q000502:physiology*; D055815:Young Adult