This study examined ERP topography during the updating and the utilization
of working memory in subjects with PTSD. Event-related potentials of 18 par
ticipants with PTSD and 18 controls were recorded from 32 scalp electrodes
during an auditory target detection task requiring the constant updating of
target identity. Midline N2 and P3 abnormalities previously noted in PTSD
during target detection were replicated. Scalp topographic data revealed su
stained reduction in activity over the right hemisphere during working memo
ry updating. Executive processes were associated with brief but widespread
right hemisphere reductions during the P3, followed by sustained, bilateral
reduction frontally. This study identifies an abnormal pattern of cortical
network function during both the updating and use of working memory in PTS
D.