The Human Amygdala by Joseph Le Doux (2008)

An excerpt, guiding our work to reduce Stress, Threat and and build Well-Being in a turbulent world.

Contact Joseph LeDoux Open Archive DOI:https://doi.org/10.1016/j.cub.2007.08.005

… Damage to the human amygdala interferes with fear conditioning and functional activity changes in the human amygdala in response to fear conditioning.

Further, exposure to emotional faces potently activates the human amygdala.

Both conditioned stimuli and emotional faces produce strong amygdala activation when presented unconsciously, emphasizing the importance of the amygdala as

  •  an implicit information processor and

  •  its role in unconscious memory.

Findings regarding the human amygdala are mainly at the level of the whole region rather than nuclei (Figure 6). 

Le Doux- FEAR -HUMAN BRAIN-1b.png

Conditioned fear in the human brain. 

Above: structural magnetic resonance image (MRI) of the human brain. The area containing the amygdala is within the box.

(A) Fear conditioning. Functional MRI (fMRI) showing amygdala activation by a conditioned stimulus (CS) after pairing with an unconditioned stimulus (US).

(B) Instructed fear. fMRI showing amygdala activation by a CS where subjects were instructed in unconditioned stimulus (US). It was not directly paired with an unconditioned stimulus (US). 

(C) Observational fear learning. fMRI showing amygdala activation by a conditioned stimulus (CS) after the subjects observed someone else undergoing fear conditioning where the CS was paired with a US. 


Structural and/or functional changes in the amygdala are associated with a wide variety of psychiatric conditions in humans. These include various anxiety disorders (PTSD, phobia and panic), depression, schizophrenia, and autism, to name a few.

This does not mean that amygdala causes these disorders. It simply means that in people who have these disorders alterations occur in the amygdala. Because each of these disorders involves fear and anxiety to some extent, the involvement of the amygdala in some of these disorders may be related to the increased anxiety in these patients.

 Conclusion

… In recent years, … scientists have turned their attention to the amygdala, revealing its structural organization, physiological mechanisms, and functions, both in animals and humans. Recent studies have also implicated the amygdala in a variety of psychiatric disorders.

In spite of this progress much remains unknown, especially about behavioral functions. However, the broad base of knowledge obtained in recent years provides a firm foundation upon which to build on in future work.