Post-traumatic stress disorder: a right temporal lobe syndrome?

Abstract

In a recent paper (Georgopoulos et al 2010 J. Neural Eng. 7 016011) we reported on the power of the magnetoencephalography (MEG)-based synchronous neural interactions (SNI) test to differentiate post-traumatic stress disorder (PTSD) subjects from healthy control subjects and to classify them with a high degree of accuracy. Here we show that the main differences in cortical communication circuitry between these two groups lie in the miscommunication of temporal and parietal and/or parieto-occipital right hemispheric areas with other brain areas. This lateralized temporal-posterior pattern of miscommunication was very similar but was attenuated in patients with PTSD in remission. These findings are consistent with observations (Penfield 1958 Proc. Natl Acad. Sci. USA 44 51-66, Penfield and Perot 1963 Brain 86 595-696, Gloor 1990 Brain 113 1673-94, Banceaud et al 1994 Brain 117 71-90, Fried 1997 J. Neuropsychiatry Clin. Neurosci. 9 420-8) that electrical stimulation of the temporal cortex in awake human subjects, mostly in the right hemisphere, can elicit the re-enactment and re-living of past experiences. Based on these facts, we attribute our findings to the re-experiencing component of PTSD and hypothesize that it reflects an involuntarily persistent activation of interacting neural networks involved in experiential consolidation.

Male veterans with PTSD exhibit aberrant neural dynamics during working memory processing: an MEG study

“…However, several MEG studies have examined patients with PTSD during the resting state or during other cognitive tasks, and these studies have shown critical connectivity and/or oscillatory aberrations associated with the disorder. [27][28][29][30][31][32] The primary goal of the present study was to characterize the oscillatory dynamics that underlie working memory encoding and maintenance and to identify potential aberrations associated with PTSD by comparing the neural activity observed in veterans with PTSD to that of healthy participants. Our selection of a verbal working memory task was based on meta-analytic findings of stronger verbal than visual memory effects in individuals with PTSD 33 and is consistent with new meta-analytic findings of larger effects for verbal learning/ memory than for nonverbal learning/memory as well as for verbal learning over delayed recall, which may link these differences to verbal encoding deficits.…”

Development and application of a diagnostic algorithm for posttraumatic stress disorder

“…We have previously demonstrated disease-specific deviations in SNI (Georgopoulos et al, 2007) and have proposed that SNI anomalies can be used as a diagnostic indicator Engdahl et al, 2010). In the present study we used least absolute shrinkage and selection operator (LASSO) regression (Tibshirani, 1996) to derive a diagnostic algorithm for PTSD based on MEG SNIs.…”

“…Indeed, impaired working memory, attention, and perceptual organization have been tied to alterations in neural synchrony in schizophrenia (Uhlhaas et al, 2009). Regarding PTSD, the most prominent deviations in SNI are hypothesized to underlie aberrant memory processing associated with re-experiencing symptoms Engdahl et al, 2010;James et al, 2013).…”

Trends in Psychological/Psychiatric Injury and Law: Continuing Education, Practice Comments, Recommendations

“…For example, Bryant et al (2010) implicated a marker role for the medial prefrontal cortex during non-conscious processing in PTSD. Engdahl et al (2010) reported that they classified with a high degree of accuracy PTSD participants and healthy controls using synchronous neural interactions as measured in magneto-encephalography.…”