The human amygdala and the induction and experience of fear.
Level 4 - case-series / case-control
Single-case experimental study / case report
PubMed 21167712 · doi:10.1016/j.cub.2010.11.042
What was done
Researchers conducted an experimental case study on a patient (SM) with focal bilateral amygdala lesions to evaluate fear induction and subjective experience. Fear was probed using exposures to live snakes and spiders, a haunted house tour, and emotionally evocative films. Assessment also included a battery of self-report questionnaires, 3 months of real-world experience sampling, and an evaluation of her life history.
What was found
The abstract provides no numerical values. It reports that the patient exhibited no overt fear across all provocative exposures and never reported experiencing more than minimal levels of fear across standardized questionnaires, 3 months of experience sampling, or traumatic life events. Other basic emotions and their corresponding subjective feelings remained intact.
Why it matters
This study provides rare, direct neuropsychological evidence that intact human amygdalae are necessary for triggering the physiological and subjective experience of fear in response to external threats.
Limits
The study is limited to a single human subject (n = 1) with rare focal bilateral amygdala damage, limiting statistical generalizability. The abstract reports no objective physiological measurements or quantitative test scores.
Cited by
- supports Patient SM, who has bilateral amygdala lesions, does not consciously experience fear when exposed to external threats including haunted houses, snakes, spiders, and horror movies.