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04-02 Topography of event-related potentials to visuoverbal working memory updating and target detection in PTSD

Published online by Cambridge University Press:  24 June 2014

MD Veltmeyer
Affiliation:
Cognitive Neuroscience Laboratory and School of Psychology, Flinders University of South Australia, Adelaide, Australia
CR Clark
Affiliation:
Cognitive Neuroscience Laboratory and School of Psychology, Flinders University of South Australia, Adelaide, Australia
AC McFarlane
Affiliation:
Department of Psychiatry, The University of Adelaide, and The Centre of Military and Veterans' Health, Adelaide, South Australia, Australia
RA Bryant
Affiliation:
School of Psychology, University of New South Wales, Sydney, New South Wales, Australia and The Brain Dynamics Centre
E Gordon
Affiliation:
The Brain Resource International Database and Brain Resource Company, Ultimo, Australia, and The Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital and Western Clinical School, University of Sydney, Australia
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Abstract

Type
Abstracts from ‘Brainwaves’— The Australasian Society for Psychiatric Research Annual Meeting 2006, 6–8 December, Sydney, Australia
Copyright
Copyright © 2006 Blackwell Munksgaard

This study examined the topography of event-related potentials (ERPs) during working memory updating in medicated (n = 14) and unmedicated (n = 20) groups of patients with PTSD and age- and gender-matched controls. ERPs were recorded from 26 scalp sites during a working memory paradigm that involved identifying when a letter appeared twice in a row in a series of letters. A large positive component at around 400 ms (P3wm) following presentation of nontarget stimuli was considered an index of working memory updating. Group differences were found in the amplitude of this component and also in P3 amplitude and latency following target stimuli. Contrary to expectations, these effects were most apparent in the medicated subgroup. Both groups of patients with PTSD exhibited delayed reaction time, but only the medicated participants were impaired in target detection accuracy. Neither ERP nor behavioural abnormalities were related to CAPS symptom scores. These results are consistent with research that suggests SSRI medication may alter working memory performance, but the results may be due to some other characteristic of the medicated participants such as differing symptom profiles.