Decreased somatosensory activity to non-threatening touch in combat veterans with posttraumatic stress disorder

Amy S Badura-Brack; Katherine M Becker; Timothy J McDermott; Tara J Ryan; Madelyn M Becker; Allison R Hearley; Elizabeth Heinrichs-Graham; Tony W Wilson

doi:10.1016/j.pscychresns.2015.06.012

Decreased somatosensory activity to non-threatening touch in combat veterans with posttraumatic stress disorder

Psychiatry Res. 2015 Aug 30;233(2):194-200. doi: 10.1016/j.pscychresns.2015.06.012. Epub 2015 Jul 2.

Authors

Amy S Badura-Brack¹, Katherine M Becker², Timothy J McDermott³, Tara J Ryan⁴, Madelyn M Becker⁵, Allison R Hearley⁵, Elizabeth Heinrichs-Graham⁶, Tony W Wilson⁷

Affiliations

¹ Department of Psychology, Creighton University, Omaha, NE, USA. Electronic address: abadura@creighton.edu.
² Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center (UNMC), Omaha, NE, USA; Center for Magnetoencephalography, UNMC, Omaha, NE, USA.
³ Department of Psychology, Creighton University, Omaha, NE, USA; Center for Magnetoencephalography, UNMC, Omaha, NE, USA.
⁴ Department of Psychology, Creighton University, Omaha, NE, USA; Department of Psychology, Simon Fraser University, Burnaby, BC, Canada.
⁵ Department of Psychology, Creighton University, Omaha, NE, USA.
⁶ Center for Magnetoencephalography, UNMC, Omaha, NE, USA; Department of Psychology, University of Nebraska-Omaha, Omaha, NE, USA.
⁷ Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center (UNMC), Omaha, NE, USA; Center for Magnetoencephalography, UNMC, Omaha, NE, USA; Department of Psychology, University of Nebraska-Omaha, Omaha, NE, USA; Department of Neurological Sciences, UNMC, Omaha, NE, USA.

Abstract

Posttraumatic stress disorder (PTSD) is a severe psychiatric disorder prevalent in combat veterans. Previous neuroimaging studies have demonstrated that patients with PTSD exhibit abnormal responses to non-threatening visual and auditory stimuli, but have not examined somatosensory processing. Thirty male combat veterans, 16 with PTSD and 14 without, completed a tactile stimulation task during a 306-sensor magnetoencephalography (MEG) recording. Significant oscillatory neural responses were imaged using a beamforming approach. Participants also completed clinical assessments of PTSD, combat exposure, and depression. We found that veterans with PTSD exhibited significantly reduced activity during early (0-125 ms) tactile processing compared with combat controls. Specifically, veterans with PTSD had weaker activity in the left postcentral gyrus, left superior parietal area, and right prefrontal cortex in response to nonthreatening tactile stimulation relative to veterans without PTSD. The magnitude of activity in these brain regions was inversely correlated with symptom severity, indicating that those with the most severe PTSD had the most abnormal neural responses. Our findings are consistent with a resource allocation view of perceptual processing in PTSD, which directs attention away from nonthreatening sensory information.

Keywords: MEG; Magnetoencephalography; Military; Oscillation; PTSD; Somatosensory; Tactile.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Afghan Campaign 2001-
Arousal / physiology*
Attention / physiology
Brain Mapping
Humans
Iraq War, 2003-2011
Magnetoencephalography*
Male
Parietal Lobe / physiopathology*
Reference Values
Sensorimotor Cortex / physiopathology*
Sensory Thresholds / physiology*
Statistics as Topic
Stress Disorders, Post-Traumatic / physiopathology*
Stress Disorders, Post-Traumatic / psychology*
Touch / physiology*
Veterans / psychology*

Abstract

Publication types

MeSH terms

Grants and funding