Abstract
Exposure to combat-related trauma often leads to lifetime functional impairments. Previous research demonstrated the effects of oxytocin (OT) administration on brain regions implicated in post-traumatic stress disorder (PTSD); yet OT’s effects on brain patterns in trauma-exposed veterans have not been studied. In the current study the effects of OT on spontaneous brain oscillatory activity were measured in 43 veterans using magnetoencephalography (MEG): 28 veterans who were exposed to a combat-related trauma and 15 trauma-unexposed controls. Participants participated in two experimental sessions and were administered OT or placebo (PBO) in a double-blind, placebo-control, within-subject design. Following OT/PBO administration, participants underwent a whole-head MEG scan. Plasma and salivary OT levels were assessed each session. Spontaneous brain activity measured during a 2-min resting period was subjected to source-localization analysis. Trauma-exposed veterans showed higher resting-state alpha (8–13 Hz) activity compared to controls in the left dorsolateral prefrontal cortex (dlPFC), specifically in the superior frontal gyrus (SFG) and the middle frontal gyrus (MFG), indicating decreased neural activity in these regions. The higher alpha activity was “normalized” following OT administration and under OT, group differences were no longer found. Increased resting-state alpha was associated with lower baseline plasma OT, reduced salivary OT reactivity, and more re-experiencing symptoms. These findings demonstrate effects of OT on resting-state brain functioning in prefrontal regions subserving working memory and cognitive control, which are disrupted in PTSD. Results raise the possibility that OT, traditionally studied in social contexts, may also enhance performance in cognitive tasks associated with working memory and cognitive control following trauma exposure.
Highlights
Combat-related post-traumatic stress disorder (PTSD) is a debilitating disorder that often leads to lifetime impairments in cognitive processing, social relationships, and emotion regulation (Yehuda, 2002; American Psychiatric Association, 2013)
Increased resting-state alpha was associated with lower baseline plasma OT, reduced salivary OT reactivity, and more reexperiencing symptoms. These findings demonstrate effects of OT on resting-state brain functioning in prefrontal regions subserving working memory and cognitive control, which are disrupted in PTSD
This suggests that higher alpha power provides an index of decreased cortical activity in these regions, and our findings suggest that OT may have some impact, albeit momentarily, on prefrontal structures suggested as among those underpinning the functional impairment in PTSD (Patel et al, 2012)
Summary
Combat-related post-traumatic stress disorder (PTSD) is a debilitating disorder that often leads to lifetime impairments in cognitive processing, social relationships, and emotion regulation (Yehuda, 2002; American Psychiatric Association, 2013). It has been suggested that amygdala hyperresponsivity and impaired top-down prefrontal control mediate the dysregulation of fear and threat-related processing in PTSD (Rauch et al, 2006) More recently it has been proposed (Patel et al, 2012) that abnormalities in three different neuro-cognitive networks may explain the range of symptoms seen in PTSD. One of these networks, the central executive network (Menon, 2011), is associated with high-level cognitive functions, such as decision making, attention control, and working memory, and is anchored in the dorsolateral prefrontal cortex (dlPFC), a region critical to proper cognitive control over emotions (Ochsner et al, 2002; Phan et al, 2005). Processes typical of PTSD such as negative appraisals of stimuli, as well as the disrupted cognitive functioning seen in PTSD, may be related to aberrant top-down signaling from this network (Patel et al, 2012)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
