UCLA

Abnormalities in basic fear conditioning and extinction processes may contribute to the development and maintenance of anxiety disorders. Specifically, the ability to distinguish between a stimulus that predicts an aversive outcome and a stimulus that predicts its absence may impact fear conditioning, extinction, and return of fear. This dissertation will include three papers investigating the role of discrimination between neutral and unsafe stimuli in the development and maintenance of conditional fear. Anxiety has been linked to discrimination (e.g., Jovanovic et al., 2013; Lissek et al., 2014), however it is unknown whether discrimination may explain the link between trait anxiety and return of fear. Study 1 examines whether discrimination mediates the relationship between trait anxiety and return of fear in a classical conditioning paradigm. There is little evidence examining whether discrimination between neutral and unsafe stimuli can be manipulated. Study 2 examines whether a positive or negative mood induction may impact discrimination and therefore impact extinction and return of fear. Study 3 investigates whether there exist functional differences when participants are presented the CS+ versus the CS-, and whether these differences accompany anxiety symptoms, altered fear extinction and extinction recall. No previous research has investigated this. In sum, we will determine whether the ability to distinguish between a neutral stimulus and an unsafe stimulus is related to trait anxiety and return of fear, whether this discrimination can be manipulated by mood, and whether the phenomenon of discrimination impacting return of fear can be observed using neuroimaging methods.