title: Abnormal frontal and parietal activity during working memory updating in post-traumatic stress disorder.
abstract: This study used event-related potentials (ERPs) to investigate the timing and scalp topography of working memory in post-traumatic stress disorder (PTSD). This study was designed to investigate ERPs associated with a specific working memory updating process. ERPs were recorded from 10 patients and 10 controls during two visual tasks where (a) targets were a specific word or (b) targets were consecutive matching words. In the first task, nontarget words are not retained in working memory. In the second task, as in delay-match-to-sample tasks, a non-target word defines a new target identity, so these words are retained in working memory. This working memory updating process was related to large positive ERPs over frontal and parietal areas at 400-800 ms, which were smaller in PTSD. Estimation of cortical source activity indicated abnormal patterns of frontal and parietal activity in PTSD, which were also observed in regional cerebral blood flow [Clark, C.R., McFarlane, A.C., Morris, P., Weber, D.L., Sonkkilla, C., Shaw, M., Marcina, J., Tochon-Danguy, H., Egan, G., 2003. Cerebral function in posttraumatic stress disorder during verbal working memory updating: a positron emission tomography study. Biological Psychiatry 53, 474-481]. Frontal and parietal cortex are known to be involved in distributed networks for working memory processes, interacting with medial temporal areas during episodic memory processes. Abnormal function in these brain networks helps to explain everyday concentration and memory difficulties in PTSD.
authors.affiliation: Cognitive Neuroscience Laboratory, The Flinders University of South Australia, GPO Box 2100, Adelaide, SA 5001, Australia. Darren.Weber@radiology.ucsf.edu
authors.forename: Darren L
authors.initials: DL
authors.lastname: Weber
authors.forename: C Richard
authors.initials: CR
authors.lastname: Clark
authors.forename: Alexander C
authors.initials: AC
authors.lastname: McFarlane
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Moores
authors.forename: Philip
authors.initials: P
authors.lastname: Morris
authors.forename: Gary F
authors.initials: GF
authors.lastname: Egan
mesh_terms: D001931:Brain Mapping / Q000295:instrumentation; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply / Q000503:physiopathology*; D006306:Health Surveys; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D008875:Middle Aged; D009415:Nerve Net / Q000098:blood supply / Q000503:physiopathology; D010296:Parietal Lobe / Q000098:blood supply / Q000503:physiopathology*; D049268:Positron-Emission Tomography; D012039:Regional Blood Flow; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000150:complications* / Q000503:physiopathology*; D013702:Temporal Lobe / Q000098:blood supply / Q000503:physiopathology