“…Therefore, according to some accounts, PTSD may be attributed to impaired safety learning (Davis, Falls, & Gewirtz, 2000; Lissek et al, 2005). The effects of nicotine exposure on safety learning and extinction have been investigated using the animal models of fear extinction and contextual safety discrimination (Elias, Gulick, Wilkinson, & Gould, 2010; Kutlu & Gould, 2014; Kutlu, Oliver, & Gould, 2014; Tian et al, 2008). For example, Elias et al (2010) found that acute nicotine enhanced extinction and impaired renewal of cued fear memories when administered during the extinction phase, whereas nicotine administration during both training and extinction phases impaired extinction and enhanced renewal of cued fear.…”