Sadeh, N., Spielberg, J. M., Miller, M. W., Milberg, W. P., Salat, D. H., Amick, M. M., Fortier, C. B., et al. (2015).
Neurobiological indicators of disinhibition in posttraumatic stress disorder.
Hum Brain Mapp ,
36, 3076-86.
AbstractDeficits in impulse control are increasingly recognized in association with posttraumatic stress disorder (PTSD). To our further understanding of the neurobiology of PTSD-related disinhibition, we examined alterations in brain morphology and network connectivity associated with response inhibition failures and PTSD severity. The sample consisted of 189 trauma-exposed Operation Enduring Freedom/Operation Iraqi Freedom veterans (89% male, ages 19-62) presenting with a range of current PTSD severity. Disinhibition was measured using commission errors on a Go/No-Go (GNG) task with emotional stimuli, and PTSD was assessed using a measure of current symptom severity. Whole-brain vertex-wise analyses of cortical thickness revealed two clusters associated with PTSD-related disinhibition (Monte Carlo cluster corrected P < 0.05). The first cluster included portions of right inferior and middle frontal gyri and frontal pole. The second cluster spanned portions of left medial orbital frontal, rostral anterior cingulate, and superior frontal gyrus. In both clusters, commission errors were associated with reduced cortical thickness at higher (but not lower) levels of PTSD symptoms. Resting-state functional magnetic resonance imaging analyses revealed alterations in the functional connectivity of the right frontal cluster. Together, study findings suggest that reductions in cortical thickness in regions involved in flexible decision-making, emotion regulation, and response inhibition contribute to impulse control deficits in PTSD. Furthermore, aberrant coupling between frontal regions and networks involved in selective attention, memory/learning, and response preparation suggest disruptions in functional connectivity may also play a role.
Miller, M. W., Wolf, E. J., Sadeh, N., Logue, M., Spielberg, J. M., Hayes, J. P., Sperbeck, E., et al. (2015).
A novel locus in the oxidative stress-related gene ALOX12 moderates the association between PTSD and thickness of the prefrontal cortex.
Psychoneuroendocrinology ,
62, 359-65.
AbstractOxidative stress has been implicated in many common age-related diseases and is hypothesized to play a role in posttraumatic stress disorder (PTSD)-related neurodegeneration (Miller and Sadeh, 2014). This study examined the influence of the oxidative stress-related genes ALOX 12 and ALOX 15 on the association between PTSD and cortical thickness. Factor analyses were used to identify and compare alternative models of the structure of cortical thickness in a sample of 218 veterans. The best-fitting model was then used for a genetic association analysis in White non-Hispanic participants (n=146) that examined relationships between 33 single nucleotide polymorphisms (SNPs) spanning the two genes, 8 cortical thickness factors, and each SNP×PTSD interaction. Results identified a novel ALOX12 locus (indicated by two SNPs in perfect linkage disequilibrium: rs1042357 and rs10852889) that moderated the association between PTSD and reduced thickness of the right prefrontal cortex. A whole-cortex vertex-wise analysis showed this effect to be localized to clusters spanning the rostral middle frontal gyrus, superior frontal gyrus, rostral anterior cingulate cortex, and medial orbitofrontal cortex. These findings illustrate a novel factor-analytic approach to neuroimaging-genetic analyses and provide new evidence for the possible involvement of oxidative stress in PTSD-related neurodegeneration.
DeGutis, J., Esterman, M., McCulloch, B., Rosenblatt, A., Milberg, W., & McGlinchey, R. (2015).
Posttraumatic Psychological Symptoms are Associated with Reduced Inhibitory Control, not General Executive Dysfunction.
J Int Neuropsychol Soc ,
21, 342-52.
AbstractAlthough there is mounting evidence that greater PTSD symptoms are associated with reduced executive functioning, it is not fully understood whether this association is more global or specific to certain executive function subdomains, such as inhibitory control. We investigated the generality of the association between PTSD symptoms and executive function by administering a broad battery of sensitive executive functioning tasks to a cohort of returning Operation Enduring Freedom/Operation Iraqi Freedom Veterans with varying PTSD symptoms. Only tasks related to inhibitory control explained significant variance in PTSD symptoms as well as symptoms of depression, while measures of working memory, measures of switching, and measures simultaneously assessing multiple executive function subdomains did not. Notably, the two inhibitory control measures that showed the highest correlation with PTSD and depressive symptoms, measures of response inhibition and distractor suppression, explained independent variance. These findings suggest that greater posttraumatic psychological symptoms are not associated with a general decline in executive functioning but rather are more specifically related to stopping automatic responses and resisting internal and external distractions.
Powell, M. A., Corbo, V., Fonda, J. R., Otis, J. D., Milberg, W. P., & McGlinchey, R. E. (2015).
Sleep Quality and Reexperiencing Symptoms of PTSD Are Associated With Current Pain in U.S. OEF/OIF/OND Veterans With and Without mTBIs.
J Trauma Stress ,
28, 322-9.
AbstractPain, a debilitating condition, is frequently reported by U.S. veterans returning from Afghanistan and Iraq. This study investigated how commonly reported clinical factors were associated with pain and whether these associations differed for individuals with a history of chronic pain. From the Boston metropolitan area, 171 veterans enrolled in the Veterans Affairs Center of Excellence were assessed for current posttraumatic stress disorder (PTSD) symptom severity, current mood and anxiety diagnoses, lifetime traumatic brain injury, combat experiences, sleep quality, and alcohol use. Hierarchical regression models were used to determine the association of these conditions with current pain. Average pain for the previous 30 days, assessed with the McGill Pain Questionnaire, was 30.07 out of 100 (SD = 25.43). Sleep quality, PTSD symptom severity, and alcohol use were significantly associated with pain (R(2) = .24), as were reexperiencing symptoms of PTSD (R(2) = .25). For participants with a history of chronic pain (n = 65), only PTSD symptoms were associated with pain (R(2) = .19). Current pain severity was associated with increased PTSD severity (notably, reexperiencing symptoms), poor sleep quality, and increased alcohol use. These data support the hypothesis that PTSD symptoms influence pain, but suggest that problems with sleep and alcohol use may exacerbate the relationship.