“…Additionally, the ventromedial prefrontal cortex and its projection to BLA, which mediate fear extinction, are hypoactive in PTSD (Hayes, Hayes, & Mikedis, ). During abstinence, smokers with PTSD experience more severe withdrawal and show increased sensitivity to both anxiety (i.e., fear of anxiety symptoms) and arousal associated with anxiety (Vujanovic, Marshall‐Berenz, Beckham, Bernstein, & Zvolensky, ). Based on the abnormal expression of BLA nAChRs in mild TBI (Almeida‐Suhett et al., ), the co‐occurrence of TBI and PTSD, and the intrinsic regulation of BLA neural circuitry by nAChRs (Jiang et al., ), increased sensitivity to anxiety and anxious arousal in abstinent smokers with PTSD may, in part, reflect the effects of nicotine on the regulation of dysfunctional BLA circuitry by nAChRs in PTSD.…”