Neural networks of information processing in posttraumatic stress disorder: a functional magnetic resonance imaging study.
BACKGROUND
Neuroimaging studies report reduced medial prefrontal cortical (particularly anterior cingulate) but enhanced amygdala response to fear signals in posttraumatic Stress Disorder (PTSD). We investigated whether anterior cingulate-amygdala dysregulation in PTSD would generalize to salient, but nonthreat related signals.


METHODS
Individuals with PTSD (n = 14) and age and sex-matched nontraumatized controls (n = 14) completed an auditory oddball paradigm adapted to functional magnetic resonance imaging at a 1.5-T field strength.


RESULTS
Controls displayed bilateral activation in ventral anterior cingulate and amygdala networks, and PTSD subjects showed bilateral dorsal anterior cingulate and amygdala activation to targets relative to nontargets. Compared to controls, PTSD subjects showed enhanced responses to targets in the dorsal and rostral anterior cingulate, and left amygdala. Whole-brain analyses confirmed the expected pattern of distributed prefrontal-parietal responses to targets in the oddball task. Greater activity in posterior parietal somatosensory regions was observed in PTSD.


CONCLUSIONS
Our findings of enhanced anterior cingulate responses in PTSD contrast with reports of reduced activity for threat stimuli, suggesting that the latter may be specific to processing of threat-related content. Activation in rostral and dorsal anterior cingulate, left amygdala and posterior parietal networks in response to salient, nonthreatening stimuli may reflect generalized hypervigilance.
Bryant
Richard A
RA
School of Psychology, University of New South Wales, Sydney, Australia. r.bryant@unsw.edu.au
Felmingham
Kim L
KL
Kemp
Andrew H
AH
Barton
Matthew
M
Peduto
Anthony S
AS
Rennie
Chris
C
Gordon
Evian
E
Williams
Leanne M
LM
D000679:Amygdala / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D016555:Matched-Pair Analysis; D008606:Mental Processes / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D013313:Stress Disorders, Post-Traumatic / Q000503:physiopathology*