Many autistic adults experience debilitating anxiety that interferes with their daily functioning. Atypical sensory processing and intolerance of uncertainty are cognitive processes linked to atypical limbic system functioning and impaired fear conditioning as potential mediators of anxiety in autism. A previous fear conditioning study using fMRI found atypical amygdala functioning in autism when the threat stimulus was only partially reinforced. The first aim of this dissertation is a multimethod examination of brain and psychophysiological response in autistic and in neurotypical adults during a fear conditioning/extinction task with the threat stimulus reinforced 100% percent of the time. We were also interested in the responses of autistic and neurotypical adults during an auditory looming task that requires no learning contingencies. We used fMRI, pupillometry, and skin conductance response as the dependent measures. Results demonstrated a significant main effect for insula activation, but not amygdala activation, during the 100%-reinforcement fear conditioning task with no between-group differences or group x condition interactions. There were likewise no condition differences (Safe vs Threat) for amygdala in the auditory looming task. However, the autism group demonstrated increased insula response to both Threat and Safe auditory conditions of the looming task, suggesting the autism group utilized alternative cognitive resources than the neurotypical group. Results indicate intact fear conditioning and extinction in autism for more certain conditions and suggests that behavioral (exposure) anxiety treatments for phobias could be useful under certain conditions. Results of this study are inconsistent with the atypical/hyperactive amygdala hypotheses of anxiety with autism and inconsistent with the portion of the South & Rodgers (2017) anxiety model regarding the importance of intolerance of uncertainty in autism samples.
College and Department
Family, Home, and Social Sciences
BYU ScholarsArchive Citation
Top Jr., David Nicholas, "A fMRI of Fear Conditioning and Auditory Looming in Autism Spectrum Disorder" (2020). Theses and Dissertations. 8599.
autism, anxiety, fear conditioning, looming, fMRI, pupillometry