Turnover of resting-state synaptic activity in posttraumatic stress disorder as revealed by magnetoencephalography

Several neuroimaging modalities used in the study of posttraumatic stress disorder (PTSD) have documented various alterations in brain structure, function, and neurocircuitry relative to controls. Studies using magnetoencephalography (MEG), which provides direct evaluation of synaptic activity, have identified anomalies in neural communication prominently involving temporal areas. Here, we shift the focus from global neural interactions to evaluate moment-to-moment change in resting-state local synaptic activity, which we refer to as MEG turnover (MEGT) in 495 US veterans. Specifically, we compared MEGT in veterans with PTSD (<i>n</i> = 184) and healthy control veterans (<i>n</i> = 311), controlling for sex and age. The findings revealed that PTSD was associated with significantly higher turnover of the MEG signal in bilateral inferior frontal/anterior temporal cortical areas, right hemispheric parietal and occipital areas, and left cerebellum, whereas it was associated with significantly reduced MEG turnover in other areas, including primarily left hemispheric temporal and occipital areas and central sulcus. The PTSD-associated anomalies in local synaptic activity are presumably due to dysregulation of neurotransmitters that influence neural communication and synaptic plasticity, the effects of which may contribute to deficits in information processing that are characteristic of PTSD.<b>NEW & NOTEWORTHY</b> Local synaptic activity can be measured by evaluating the moment-to-moment change, or turnover, of the magnetoencephalography (MEG) signal. Here we found that posttraumatic stress disorder (PTSD) was associated with highly significant differences in resting-state MEG turnover (MEGT) compared with controls, the direction of which varied across the cortex. Since synaptic activity depends on neurotransmitters, these findings are consistent with models implicating neurotransmitter dysregulation in PTSD.