Top-Down and Bottom-Up Fear Regulation: Experimental Combinations to Reduce the Return of Fear and an Examination of its Neural Correlates

The regulation of fear can be considered as driven from stimulus properties, considered bottom-up, and cognitive constructions, considered top-down. This dissertation contains three papers that investigated how these approaches may complement one another for the purposes of clinical translation to optimize long-term fear amelioration in treatments for fear-related disorders.In Study 1, a fear-conditioning experiment was conducted manipulating the use of a low-cost, re-evaluative, and contingency-directed cognitive reappraisal against passive and active control conditions (i.e., react-as-normal and expressive suppression). The experiment examined how this strategy changed responses during extinction training and during a test of rapid reacquisition one-week later. In Study 2, the experiment was replicated twice. The first replaced the test of rapid reacquisition with an induction of fear reinstatement. The second replaced the test of rapid reacquisition with an induction of context renewal. Results indicated that reappraisal led to faster reductions in threat expectancy to the CS- during extinction training relative to suppression. This was not observed when extinction training featured CSs overlaid atop visual contexts. Results also indicated that in one of three experiments, reappraisal, relative to reacting as normal, led to increases in CS+ valence after extinction training and reductions in the spontaneous recovery of skin conductance responses. Reappraisal, relative to suppression, also led to faster recovery of CS+ US expectancy after fear reinstatement. Suppression led to greater skin conductance responding to the CS- relative to reappraisal and reacting as normal during rapid reacquisition and greater skin conductance responding to the CS+ during context renewal relative to reacting as normal.Study 3 examined how individuals who express above average spontaneous recovery in skin conductance responses differentially recruit neural activity in structures that putatively implement fear (amygdala, BNST, anterior insula), top-down regulation (dlPFC and vlPFC) and bottom-up regulation (vmPFC and sgACC) during a test of spontaneous recovery 24-48 hours after fear extinction training. Results suggested sparse evidence for fear over-generation in fear regions, and more evidence for misregulation, underregulation/disconnection, and competitive co-regulation in regions that implement fear regulation. Results are discussed in terms of the granular mechanisms underlying extinction and cognitive reappraisal, and implications for clinical application