Figure 5. Dynamics of Working Memory Dysfunction in Posttraumatic Stress Disorder (PTSD).

Group mean functional images (beamformer, pseudo-t scale) for controls and veterans with PTSD are displayed in the sagittal orientation for select time windows of the encoding (top) and maintenance (bottom) periods. Note that pseudo-t values reflect the differential power per voxel between an active period (shown below image) and a pre-stimulus baseline period. (Left) Both groups exhibited strong alpha-beta oscillatory responses in the left hemispheric fronto-temporal cortices throughout the encoding phase, which narrowed to include only the alpha band during maintenance. Interestingly, there were no group differences in these left fronto-temporal circuits in any time period. (Right) In contrast, veterans with PTSD exhibited significantly stronger oscillatory responses in multiple right hemispheric brain regions during the encoding and maintenance periods relative to demographically-matched controls. The critical regions included the right inferior frontal gyrus (homologue of Broca's area), right supramarginal gyrus, and right temporal cortices (p < 0.005, corrected). Note that right hemispheric group differences were observed in other time periods (not shown) as well.⁶⁷