Cerebral function in posttraumatic stress disorder during verbal working memory updating: a positron emission tomography study.
BACKGROUND
This study examined cerebral function in posttraumatic stress disorder (PTSD) during the updating of working memory to trauma-neutral, verbal information.


METHODS
Ten PTSD and matched control subjects completed a visuoverbal target detection task involving continuous updating (Variable target condition) or no updating (Fixed target condition) of target identity, with updating activity estimated by condition comparison.


RESULTS
Normal updating activity using this paradigm involved bilateral activation of the dorsolateral prefrontal cortex (DLPFC) and inferior parietal lobe. The PTSD group lacked this activation in the left hemisphere and was significantly different from control subjects in this regard, but showed additional activation in the superior parietal lobe, bilaterally.


CONCLUSIONS
The pattern of parietal activation suggests a dependence on visuospatial coding for working memory representation of trauma-neutral, verbal information. Group differences in the relative involvement of the DLPFC indicate less dependence in PTSD on the executive role normally attributed to the left DLPFC for monitoring and manipulation of working memory content in posterior regions of the brain.
Clark
C Richard
CR
School of Psychology, Flinders Medical Research Institute, Flinders University, Adelaide, Australia.
McFarlane
Alexander C
AC
Morris
Philip
P
Weber
Darren L
DL
Sonkkilla
Cynon
C
Shaw
Marnie
M
Marcina
Jackie
J
Tochon-Danguy
H J
HJ
Egan
Gary F
GF
D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology*; D017397:Prefrontal Cortex / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology*; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000378:metabolism* / Q000503:physiopathology* / Q000523:psychology; D014055:Tomography, Emission-Computed; D014796:Visual Perception / Q000502:physiology*