The Man Who Lost the Ability to Feel Fear
A woman known in science as SM has a rare condition that destroyed her amygdala, leaving her unable to experience fear — she'll pet snakes, walk through haunted houses, and stay calm at knifepoint. Her case rewrote what neuroscientists thought fear was for, until researchers found the one thing that could still terrify her. This is the story of what fear protects us from, and what happens when the alarm goes silent.
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Urbach-Wiethe disease caused bilateral calcification of Patient S.M.'s amygdala, removing her ability to feel fear.
Patient S.M. survived being held at knifepoint without experiencing the typical fight or flight response.
Without an amygdala, the brain fails to flag urgent environmental information like dangerous snakes or spiders.
Directing gaze toward the eyes restores the ability to identify fear in other people's faces.
Inhaling thirty-five percent carbon dioxide triggered a primal panic response despite the lack of an amygdala.
The brain uses a separate internal monitoring system to detect survival crises like suffocation.
- 01Intro1 min
- 02The Woman Without an Alarm2 min
- 03Testing the Limits of Fearlessness3 min
- 04The Suffocation Exception3 min
- 05The Distributed Fear Network2 min
- 06Outro1 min
- S.M. (patient) - Wikipedia
- The human amygdala and the induction and experience of fear
- Living Without an Amygdala
- Fearless Woman Lacks Key Part of Brain
- The Fearless SM: Woman Missing Amygdala - Neuroscience News
- Fear and panic in humans with bilateral amygdala damage
- A mechanism for impaired fear recognition after amygdala damage
- Altered experience of emotion following bilateral amygdala damage
- “Now You See Me”: A Neural Pathway Independent of the Amygdala ...
- Fear bypasses the amygdala | Nature Reviews Neuroscience
- Scientists discover a new pathway for fear deep within the brain
- Fear, anxiety, and the extended amygdala—Absence of evidence for ...
- The Nature and Neurobiology of Fear and Anxiety - PMC - NIH
- A molecularly defined amygdala-independent tetra-synaptic forebrain-to-hindbrain pathway for odor-driven innate fear and anxiety - Nature Neuroscience
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