Attention control training may address aberrant fluctuations in attention allocation in PTSD, thereby reducing PTSD symptoms. Further study of treatment efficacy and its underlying neurocognitive mechanisms is warranted.

IntroductionPosttraumatic stress disorder (PTSD) is a psychiatric disorder characterized by re-experiencing, avoidance, negative alterations in mood and cognition, and physiologic arousal symptoms, which may develop subsequent to a traumatic event (e.g., combat).1,2 The lifetime prevalence of PTSD in the United States is roughly 7%-9%; 3,4 however, prevalence rates among recent combat veterans are estimated at 13%-22%. 5,6 Previous studies have demonstrated that patients with PTSD experience deficits in memory, attention and executive functioning. [7][8][9] More specifically, a recent meta-analysis of 60 neurocognitive studies comparing patients with PTSD to healthy controls (4108 participants) found the largest effect sizes reflecting deficiencies in the PTSD group for verbal learning, information processing speed and attention/working memory. 10 The etiology of these functional deficits is not entirely clear, but they do appear to be contributing factors to PTSD symptomatology. 11,12Working memory is an essential component of information processing and is typically divided into 3 cognitive subprocesses: encoding, maintenance and retrieval.13 Studies using functional magnetic resonance imaging (fMRI) and positron emission tomography 14 have identified the network architecture serving working memory processing in healthy adults. Critical brain regions include the prefrontal cortex, superior parietal lobule and adjacent areas, lateral occipital regions, cerebellum, and the left supramarginal gyrus and contiguous temporal regions.14,15 While such studies elucidate brain regions responsible for general working memory function, they rely on indirect measures of brain activity (e.g., local blood oxygenation), making it difficult to dissociate which areas are active during each phase of working memory. Background: Posttraumatic stress disorder (PTSD) is associated with executive functioning deficits, including disruptions in working memory. In this study, we examined the neural dynamics of working memory processing in veterans with PTSD and a matched healthy control sample using magnetoencephalography (MEG). Methods: Our sample of recent combat veterans with PTSD and demographically matched participants without PTSD completed a working memory task during a 306-sensor MEG recording. The MEG data were preprocessed and transformed into the time-frequency domain. Significant oscillatory brain responses were imaged using a beamforming approach to identify spatiotemporal dynamics. Results: Fifty-one men were included in our analyses: 27 combat veterans with PTSD and 24 controls. Across all participants, a dynamic wave of neural activity spread from posterior visual cortices to left frontotemporal regions during encoding, consistent with a verbal working memory task, and was sustained throughout maintenance. Differences related to PTSD emerged during early encoding, with patients exhibiting stronger α oscillatory responses than controls in the right inferior frontal gyrus (IFG). Differences spread to the right supramarginal ...

Posttraumatic stress disorder (PTSD) is a major psychiatric disorder that is prevalent in combat veterans. Previous neuroimaging studies have found elevated amygdala activity in PTSD in response to threatening stimuli, but previous work has lacked the temporal specificity to study fast bottom-up fear responses involving the amygdala. Forty-four combat veterans, 28 with PTSD and 16 without, completed psychological testing and then a face-processing task during magnetoencephalography (MEG). The resulting MEG data were pre-processed, transformed into the time-frequency domain, and then imaged using a beamforming approach. We found that veterans with PTSD exhibited significantly stronger oscillatory activity from 50 to 450 ms in the left amygdala compared to veterans without PTSD while processing threatening faces. This group difference was not present while viewing neutral faces. The current study shows that amygdala hyperactivity in response to threatening cues begins quickly in PTSD, which makes theoretical sense as an adaptive bottom-up fear response.