Elsevier

Journal of Psychiatric Research

Volume 91, August 2017, Pages 169-176
Journal of Psychiatric Research

Glutamate/glutamine concentrations in the dorsal anterior cingulate vary with Post-Traumatic Stress Disorder symptoms

https://doi.org/10.1016/j.jpsychires.2017.04.010Get rights and content

Abstract

Trauma and stress-related disorders (e.g., Acute Stress Disorder; ASD and Post-Traumatic Stress Disorder; PTSD) that develop following a traumatic event are characterized by cognitive-affective dysfunction. The cognitive and affective functions disrupted by stress disorder are mediated, in part, by glutamatergic neural systems. However, it remains unclear whether neural glutamate concentrations, measured acutely following trauma, vary with ASD symptoms and/or future PTSD symptom expression. Therefore, the current study utilized proton magnetic resonance spectroscopy (1H-MRS) to investigate glutamate/glutamine (Glx) concentrations within the dorsal anterior cingulate cortex (ACC) of recently (i.e., within one month) traumatized individuals and non-traumatized controls. Although Glx concentrations within dorsal ACC did not differ between recently traumatized and non-traumatized control groups, a positive linear relationship was observed between Glx concentrations and current stress disorder symptoms in traumatized individuals. Further, Glx concentrations showed a positive linear relationship with future stress disorder symptoms (i.e., assessed 3 months post-trauma). The present results suggest glutamate concentrations may play a role in both acute and future post-traumatic stress symptoms following a traumatic experience. The current results expand our understanding of the neurobiology of stress disorder and suggest glutamate within the dorsal ACC plays an important role in cognitive-affective dysfunction following a traumatic experience.

Section snippets

Participants

A total of 39 participants were recruited for the present study. Twenty-one TE individuals were recruited from the University of Alabama at Birmingham's Acute Trauma Care Unit, Trauma Burn Nursing Unit, Trauma Burn Intensive Care Unit, and Emergency Department, and were scanned within 30 days of trauma exposure. TE participants had experienced 1) a physical injury requiring a visit to a trauma unit/emergency department and 2) exposure to a traumatic event identified on the Posttraumatic

Results

A series of Chi-square and independent samples t-tests compared self-report and demographic measures between the TE and NTE groups. The TE and NTE groups did not differ in race, sex, handedness, or FSIQ. However, there was a small but significant difference in age between TE and NTE participants (Table 1). As expected, PDS scores differed between the TE and NTE groups (Table 1). Specifically, the TE group reported greater post-traumatic stress symptom severity (i.e., higher PDS total scores and

Discussion

There is significant variability in susceptibility to post-traumatic stress following a trauma. Specifically, only a fraction of those exposed to trauma ultimately develop a stress-related disorder such as ASD or PTSD. Further, these individuals show considerable variability in the severity of cognitive-affective disruptions induced by trauma exposure. Cognitive-affective processes are mediated by brain networks whose function is partially dependent on glutamatergic systems. Therefore,

Funding

This research was supported by the University of Alabama at Birmingham, Department of Physical Medicine and Rehabilitation's Functional Neurorecovery Pilot Grants Initiative (A. J. K. & D. C. K.), the University of Alabama at Birmingham, Office of Equity and Diversity's CMFSDP Fellowship (N. G. H.), and the Ford Foundation's Predoctoral Fellowship (N. G. H.). The funding sources had no role in the design, collection, analysis, or interpretation of the data.

Acknowledgements

The authors would like to thank Muriah Wheelock, Edwin Cook III, and Rajesh Kana for their assistance with this manuscript. This research was supported by the University of Alabama at Birmingham, Department of Physical Medicine and Rehabilitation's Functional Neurorecovery Pilot Grants Initiative (A. J. K. & D. C. K.), the University of Alabama at Birmingham, Office of Equity and Diversity's CMFSDP Fellowship (N. G. H.), and the Ford Foundation‘s Predoctoral Fellowship (N. G. H.).

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