The Origin of Concentration Problems in Posttraumatic Stress Disorder.
Abstract: Posttraumatic stress disorder (PTSD) is an often-debilitating
psychiatric disorder that emerges in some individuals after experiencing a traumatic event.
Hyperarousal-related symptoms include "problems with concentration" and most related
research demonstrates that trauma-related and emotional cues are particularly distracting
for individuals with PTSD. Neurocircuitry models of PTSD ... read morehave revealed functional
abnormalities in fear memory-related structures such as the dorsal anterior cingulate
cortex (dACC), further emphasizing the traumatic event and emotion. However, the dACC is
involved in processes other than fear memory expression, such as exertion and maintenance
of top-down cognitive control that prevents potentially distracting cues from capturing
attention. The current studies aim to determine whether PTSD is associated with such
fundamental impairment to the top-down attention system that even trauma-unrelated,
emotionally neutral stimuli can disrupt concentration by capturing attention. They also
address the origin of concentration problems and functional brain abnormalities, which may
be acquired characteristics of PTSD or of trauma exposure, or may reflect pre-existing
familial vulnerability to PTSD. We used two non-emotional paradigms, the Posner Cueing Task
and the Multi-Source Interference Task (MSIT), to assess the propensity for attentional
capture and dACC function in PTSD. The Posner task was presented to two participant groups:
1) Vietnam War combat veterans with or without current PTSD and their combat-unexposed
monozygotic twins, and 2) undergraduates with varying levels of trauma exposure. Veterans
with PTSD and their cotwins were more prone to exogenous attentional capture than veterans
without PTSD and their cotwins, demonstrating that this abnormality is a familial
vulnerability factor. As further evidence of this vulnerability factor, exogenous
attentional capture in combat-unexposed individuals correlated with PTSD hyperarousal
symptoms in their combat-exposed identical twins. The undergraduate cohort produced null
findings. The MSIT task, which reliably activates the dACC of healthy individuals, was
presented to the twin cohort during fMRI. The results demonstrated that dACC
hyperresponsiveness during the MSIT task is a familial vulnerability factor. These results
are discussed in the context of dACC functions such as cognitive control and the detection
of stressor controllability.
Thesis (Ph.D.)--Tufts University, 2015.
Submitted to the Dept. of Psychology.
Advisor: Lisa Shin.
Committee: George Bush, Jessica Remedios, Scott Orr, and Joseph DeBold.
Keywords: Psychology, Neurosciences, and Psychobiology.read less