Functional connectivity of dissociative responses in posttraumatic stress disorder: a functional magnetic resonance imaging investigation.
BACKGROUND
The purpose of this study was to assess interregional brain activity covariations during traumatic script-driven imagery in subjects with posttraumatic stress disorder (PTSD).


METHODS
Functional magnetic resonance imaging and functional connectivity analyses were used to assess interregional brain activity covariations during script-driven imagery in PTSD subjects with a dissociative response, PTSD subjects with a flashback response, and healthy control subjects.


RESULTS
Significant between-group differences in functional connectivity were found. Comparing dissociated PTSD patients and control subjects' connectivity maps in the left ventrolateral thalamus (VLT) [-14, -16, 4] revealed that control subjects had higher covariations between activations in VLT and in the left superior frontal gyrus (Brodmann's area [BA] 10), right parahippocampal gyrus (BA 30), and right superior occipital gyrus (BA 19, 39), whereas greater covariation with VLT in dissociated PTSD subjects occurred in the right insula (BA 13, 34), left parietal lobe (BA 7), right middle frontal gyrus (BA 8), superior temporal gyrus (BA 38, 34), and right cuneus (BA 19). Comparing dissociated PTSD and flashback PTSD connectivity maps in the right cingulate gyrus [3, 16, 30] revealed that dissociated PTSD subjects had higher covariations between activations in this region and the left inferior frontal gyrus (BA 47).


CONCLUSIONS
Greater activation of neural networks involved in representing bodily states was seen in dissociated PTSD subjects than in non-PTSD control subjects. These findings might illuminate the mechanisms underlying distorted body perceptions often observed clinically during dissociative episodes.
Lanius
Ruth A
RA
Department of Psychiatry, University of Western Ontario, London, Ontario, Canada. ruth.lanius@lhsc.on.ca
Williamson
Peter C
PC
Bluhm
Robyn L
RL
Densmore
Maria
M
Boksman
Kristine
K
Neufeld
Richard W J
RW
Gati
Joseph S
JS
Menon
Ravi S
RS
D000063:Accidents, Traffic / Q000523:psychology; D000293:Adolescent; D000328:Adult; D002648:Child; D002649:Child Abuse / Q000523:psychology; D002650:Child Abuse, Sexual / Q000523:psychology; D002675:Child, Preschool; D004213:Dissociative Disorders / Q000473:pathology* / Q000523:psychology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000502:physiology; D009415:Nerve Net / Q000473:pathology; D010775:Photic Stimulation; D011569:Psychiatric Status Rating Scales; D013313:Stress Disorders, Post-Traumatic / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology; D014754:Violence