Functional disconnections in the direct and indirect amygdala pathways for fear processing in schizophrenia.
BACKGROUND
Schizophrenia patients show reduced neural activity, relative to controls, in the amygdala and its projection to the medial prefrontal cortex (MPFC) in response to fear perception. In this study we tested the hypothesis that schizophrenia is characterized by abnormal functional connectivity in the amygdala network underlying fear perception.


METHODS
Functional MRI images were acquired from 14 schizophrenia patients and 14 matched healthy control subjects during an emotion perception task, in which fearful and neutral facial expression stimuli were presented pseudorandomly under nonconscious (using masking) and conscious conditions. Both subtraction and functional connectivity analyses were undertaken using a region of interest approach.


RESULTS
In response to fearful facial expressions, schizophrenia patients displayed reduced amygdala activity, compared to controls, in both the conscious and nonconscious conditions. The amygdala displayed a reversal of the normal pattern of connectivity with the brainstem, visual cortex, and also with the dorsal and ventral divisions of the MPFC in the schizophrenia patients.


CONCLUSIONS
The presence of functional disconnections in amygdala pathways suggests that schizophrenia patients have a failure in coordinating their automatic orienting to salient signals and the associated prefrontal monitoring of these signals.
Das
Pritha
P
Neuroscience Institute of Schizophrenia and Allied Disorders, Darlinghurst, NSW 2010, Australia. prithad@psych.usyd.edu.au
Kemp
Andrew H
AH
Flynn
Gary
G
Harris
Anthony W F
AW
Liddell
Belinda J
BJ
Whitford
Thomas J
TJ
Peduto
Anthony
A
Gordon
Evian
E
Williams
Leanne M
LM
D000328:Adult; D000679:Amygdala / Q000503:physiopathology*; D001364:Awareness / Q000502:physiology; D001933:Brain Stem / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000503:physiopathology*; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013477:Superior Colliculi / Q000503:physiopathology; D014793:Visual Cortex / Q000503:physiopathology