The Origin of Physiological and Functional Brain Abnormalities During Fear Conditioning and Extinction in Identical Twins Discordant for PTSD and Trauma Exposure
Kaur, Navneet.
2019
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Psychophysiological and neuroimaging research has demonstrated
impaired fear conditioning and extinction responses in PTSD. However, the origin
of these biological abnormalities has not yet been identified. The purpose of this
study was to determine whether these psychophysiological and neural abnormalities
in PTSD are familial vulnerability factors, effects of trauma exposure, or are
acquired ... read morecharacteristics of PTSD. In this case-control twin study, monozygotic
twin pairs discordant for combat exposure completed a fear conditioning and
extinction paradigm. Skin conductance response (SCR) and brain activation during
the task were measured. Results indicate that lesser differential SCRs, and
greater activations in the left and right insula during early trials of
conditioning may be familial vulnerability factors of PTSD. Additionally, lesser
differential SCRs and greater activations in the ventromedial prefrontal cortex
(vmPFC) and right insula during trials of early versus late extinction learning
may be familial vulnerability factors for PTSD. Furthermore, greater activation in
the dorsal anterior cingulate cortex (dACC) during late extinction learning, and
lesser activation in the vmPFC and greater activation in the rostral ACC (rACC)
during early extinction recall are attributable to combat exposure, independent of
the development of PTSD. These findings show that individuals with PTSD had lesser
differential conditioning than individuals without PTSD and lesser differential
SCR during early versus late extinction, further supporting the difficulty
observed in individuals with PTSD to differentially condition.
Thesis (Ph.D.)--Tufts University, 2019.
Submitted to the Dept. of Psychology.
Advisor: Lisa Shin.
Committee: Elizabeth Race, Marie-France Marin, and Heather Urry.
Keywords: Experimental psychology, Neurosciences, and Physiological psychology.read less - ID:
- nk322s863
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