Amygdala — Function, Location & Quiz
The amygdala does not simply generate fear; it learns which cues predict danger and changes attention, autonomic response and memory accordingly. It works closely with the hippocampus, but the distinction matters: hippocampus binds context, while amygdala assigns emotional significance.
Patient S.M. made that role unusually visible because bilateral amygdala damage reduced fear experience and recognition of fearful faces. In anxiety and PTSD the problem is not a missing structure but an imbalanced circuit, with strong amygdala responses and weaker prefrontal extinction control.
Test this anatomy in the Brain Regions Quiz or open the interactive 3D brain model.
Location and anatomical map
Fear processing, emotional memory, threat detection, social cognition.
Atlas category: subcortical.
Functions
- Fear conditioning and threat detection
- Emotional memory formation and enhancement
- Social cognition — reading facial expressions (especially fear)
- Modulating memory consolidation in hippocampus via stress hormones
Pathways and connections
- Thalamus → Amygdala (low road — fast, crude threat detection)
- Cortex → Amygdala (high road — slow, detailed evaluation)
- Amygdala → Hypothalamus (fight-or-flight response)
- Amygdala ↔ vmPFC (fear extinction, emotion regulation)
- Amygdala → Hippocampus (emotional memory tagging)
Clinical relevance
- Patient SM (Urbach-Wiethe disease) — bilateral amygdala calcification → no fear, impaired fear face recognition
- SM approached snakes and haunted houses with curiosity, not fear
- PTSD: amygdala hyperactivity + vmPFC hypoactivity (impaired fear extinction)
- Klüver-Bucy syndrome: bilateral temporal lobe (incl. amygdala) → oral exploration, hypersexuality, flatness
Key facts
- LeDoux: the 'low road' (thalamus→amygdala) is faster than cortical route by ~12ms
- Amygdala enhances memory for emotional events via norepinephrine in hippocampus
- Fear conditioning: amygdala learns CS-US associations in just one trial
- Fear extinction requires vmPFC inhibiting amygdala — basis of exposure therapy
Exam tip
Amygdala = fear learning. Two roads: fast (thalamus) and slow (cortex). Extinction = vmPFC inhibiting amygdala, NOT erasing the fear memory.
Common questions
What does the amygdala do?
It supports threat detection, fear conditioning, emotional memory and interpretation of socially important facial signals, especially fear.
How do the amygdala and hippocampus differ?
The amygdala emphasizes emotional significance and can strengthen memory under arousal; the hippocampus binds contextual and episodic details such as what happened, where and when.
Does fear extinction erase an amygdala memory?
No. Extinction is new learning, supported by ventromedial prefrontal inhibition of amygdala responses, rather than deletion of the original fear association.