This page focuses on the neuropsychiatric manifestations associated with lesions of the amygdala.

Cognitive, behavioural, and psychiatric effects of lesions may also arise through mechanisms other than network disruption; the potential contribution of these mechanisms can be considered using the Neuropsychiatric Effects of CNS Structural Abnormalities (NECSA) classification.

Amygdala

Page most recently updated 7 September 2026

● Lesion manifestations

▪ Impaired recognition of fear and other emotional expressions

▪ Reduced emotional salience

▪ Altered social judgement

▪ Emotional blunting

▪ Bilateral lesions may produce:

◦ Klüver–Bucy syndrome, characterized by:

Hyperorality

Hypersexuality

Placidity

Altered emotional responses

● Clinical pearls

▪ Amygdala dysfunction does not simply mean “loss of emotion”; it primarily affects the assignment of emotional significance.

▪ Patients may understand facts but fail to appreciate their emotional consequences.

▪ Amygdala involvement is important in neuropsychiatric presentations of temporal lobe disease.

Clinical reminder: consider NECSA mechanisms

(Neuropsychiatric Effects of CNS Structural Abnormalities)

When a structural lesion is identified in a patient presenting with neuropsychiatric symptoms, consider which NECSA mechanisms may explain these symptoms:

● Network disruption

Disruption of functional networks due to the presence of the lesion

● Electrical disturbance

Ictal, preictal, postictal, or interictal effects due to epileptic activity associated with the lesion (particularly if involving or adjacent to cortex)

● Chemical (endocrine) effects

Hormone excess or deficiency caused by the lesion (particularly if involving the pituitary gland or hypothalamus)

● Side effects of treatment

Effects of medications, surgery, radiotherapy, or other interventions

● Alternative explanations

The lesion may be incidental, or symptoms may arise from another cause (e.g., psychological response to illness or a comorbid psychiatric condition)

Selected references and further reading — Lesional lens

Rohlfing T, Zahr NM, Sullivan EV, Pfefferbaum A. The SRI24 multichannel atlas of normal adult human brain structure. Hum Brain Mapp. 2010;31(5):798–819.

Clark DL, Boutros NN, Mendez MF. The brain and behavior: an introduction to behavioral neuroanatomy. 4th ed. Cambridge: Cambridge University Press; 2018.

Brazis PW, Masdeu JC, Biller J. Localization in clinical neurology. 7th ed. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins; 2016.

Blumenfeld H. Neuroanatomy through clinical cases. 3rd ed. New York: Oxford University Press; 2021.

Hassan I. The neuropsychiatric effects of CNS structural abnormalities (NECSA) classification: an aid to differential diagnosis. Aust N Z J Psychiatry. 2015;49(10):943.

Arciniegas DB, Yudofsky SC, Hales RE, editors. The American Psychiatric Association Publishing textbook of neuropsychiatry and clinical neurosciences. 6th ed. Washington (DC): American Psychiatric Association Publishing; 2018.

Agrawal N, Faruqui R, Bodani M, editors. Oxford textbook of neuropsychiatry. Oxford: Oxford University Press; 2020.