The Psychology Index

The Psychology Index is an independent reference, written from scratch in plain English.

Brain and behaviour

Amygdala

The amygdala is a small, almond-shaped cluster of nuclei deep in each temporal lobe of the brain. It plays an important role in emotional learning and in detecting what matters in the environment.

Learning about threat

Research on fear conditioning in animals, particularly by Joseph LeDoux and colleagues, identified the amygdala as central to learning that a signal predicts danger. Input reaches it by routes from sensory areas, and it connects to systems that produce bodily and behavioural responses.

Beyond fear

In humans, damage to the amygdala can impair the recognition of fear in faces, as documented in studies of a rare patient. The structure also responds to rewarding and novel stimuli and influences how strongly emotional events are stored in memory. Many researchers now describe it as helping to register relevance, which is much broader than fear alone.

Why simple labels mislead

Calling the amygdala the fear centre overstates things. Some people with amygdala damage still feel fear in certain circumstances, and emotions rely on distributed networks. LeDoux himself has argued for separating defensive responses from the conscious experience of fear. The amygdala's many nuclei also differ in function.

Further reading

  • LeDoux, J. E. (2000). Emotion circuits in the brain. Annual Review of Neuroscience, 23, 155-184.
  • Adolphs, R., Tranel, D., Damasio, H., & Damasio, A. (1994). Impaired recognition of emotion in facial expressions following bilateral damage to the human amygdala. Nature, 372, 669-672.
  • Phelps, E. A., & LeDoux, J. E. (2005). Contributions of the amygdala to emotion processing: From animal models to human behavior. Neuron, 48, 175-187.