Effects of trauma-related cues on pain processing in posttraumatic stress disorder: an fMRI investigation.
BACKGROUND
Imaging studies of pain processing in primary psychiatric disorders are just emerging. This study explored the neural correlates of stress-induced analgesia in individuals with posttraumatic stress disorder (PTSD). It combined functional magnetic resonance imaging (fMRI) and the traumatic script-driven imagery symptom provocation paradigm to examine the effects of trauma-related cues on pain perception in individuals with PTSD.


METHODS
The study included 17 patients with PTSD and 26 healthy, trauma-exposed controls. Participants received warm (nonpainful) or hot (painful) thermal stimuli after listening to a neutral or a traumatic script while they were undergoing an fMRI scan at a 4.0 T field strength.


RESULTS
Between-group analyses revealed that after exposure to the traumatic scripts, the blood oxygen level-dependent (BOLD) signal during pain perception was greater in the PTSD group than the control group in the head of the caudate. In the PTSD group, strong positive correlations resulted between BOLD signal and symptom severity in a number of brain regions previously implicated in stress-induced analgesia, such as the thalamus and the head of the caudate nucleus. Trait dissociation as measured by the Dissociative Experiences Scale correlated negatively with the right amygdala and the left putamen.


CONCLUSIONS
This study included heterogeneous traumatic experiences, a different proportion of military trauma in the PTSD versus the control group and medicated patients with PTSD.


CONCLUSIONS
These data indicate that in patients with PTSD trauma recall will lead in a state-dependent manner to greater activation in brain regions implicated in stress-induced analgesia. Correlational analyses lend support to cortical hyperinhibition of the amygdala as a function of dissociation.
Neuroscience Program, University of British Columbia, Vancouver, BC.
Marla J S
MJ
Mickleborough
Judith K
JK
Daniels
Nicholas J
NJ
Coupland
Raymond
R
Kao
Peter C
PC
Williamson
Ulrich F
UF
Lanius
Kathy
K
Hegadoren
Allan
A
Schore
Maria
M
Densmore
Todd
T
Stevens
Ruth A
RA
Lanius
D000328:Adult; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D003463:Cues; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged; D058748:Pain Perception / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology; D013313:Stress Disorders, Post-Traumatic / Q000150:complications / Q000503:physiopathology*; D014947:Wounds and Injuries / Q000150:complications / Q000503:physiopathology*