Emerging Approaches to Neurocircuits in PTSD and TBI: Imaging the Interplay of Neural and Emotional Trauma

Abstract

Posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) commonly co-occur in general and military populations and have a number of overlapping symptoms. While research suggests that TBI is risk factor for PTSD and that PTSD may mediate TBI-related outcomes, the mechanisms of these relationships are not well understood. Neuroimaging may help elucidate patterns of neurocircuitry both specific and common to PTSD and TBI and thus help define the nature of their interaction, refine diagnostic classification, and may potentially yield opportunities for targeted treatments. In this review, we provide a summary of some of the most common and the most innovative neuroimaging approaches used to characterize the neural circuits associated with PTSD, TBI, and their comorbidity. We summarize the state of the science for each disorder and describe the few studies that have explicitly attempted to characterize the neural substrates of their shared and dissociable influence. While some promising targets in the medial frontal lobes exist, there is not currently a comprehensive understanding of the neurocircuitry mediating the interaction of PTSD and TBI. Future studies should exploit innovative neuroimaging approaches and longitudinal designs to specifically target the neural mechanisms driving PTSD-TBI-related outcomes.

Increased Behavioral Deficits and Inflammation in a Mouse Model of Co-Morbid Traumatic Brain Injury and Post-Traumatic Stress Disorder

“…Both diseases are common; approximately 25 million Americans have PTSD and there are 2.6 million new cases of TBI annually ( http://www.cdc.gov/TraumaticBrainInjury/data/index.html ). Multiple studies have shown that TBI increases the probability of developing PTSD, yet the underlying mechanisms are unknown ( Bryant, 2011 ; Yurgil et al., 2014 ; Spadoni et al., 2018 ).…”

Brain Amygdala Volume Increases in Veterans and Active-Duty Military Personnel With Combat-Related Posttraumatic Stress Disorder and Mild Traumatic Brain Injury

“…The normalization to ICV also accounts for the voxel size variation. 20 Unfortunately, the number of neuroimaging studies of combat-related co-morbid mTBI and PTSD are sparse 9,21,22 . In the case of amygdala volume and PTSD, several volumetric imaging analyses have presented seemingly contradictory findings.…”

Context is key: glucocorticoid receptor and corticosteroid therapeutics in outcomes after traumatic brain injury

“…This impaired response during the vulnerable post-injury period can result in loss of essential immediate anti-inflammatory actions of GC, exacerbating the chronic inflammatory state (Komoltsev and Gulyaeva, 2022 ). Additionally, survivors of TBI have an increased likelihood of developing post-traumatic stress disorder (PTSD), which can amplify the stress and trauma experienced post-TBI (Spadoni et al, 2018 ). Chronic variable stress (CVS) is frequently used to model PTSD in rodents, and CVS followed by TBI causes greater cognitive deficits than either CVS or TBI alone (Fesharaki-Zadeh et al, 2020 ).…”