This page focuses on the neuropsychiatric manifestations associated with lesions of the anterior thalamic radiation (ATR).
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.
Anterior thalamic radiation (ATR)
Page most recently updated 7 September 2026
● Lesion manifestations
▪ Disruption of frontothalamic connectivity may lead to:
◦ Apathy and reduced initiation
◦ Reduced motivation and goal-directed behaviour
◦ Executive dysfunction
◦ Cognitive slowing
◦ Reduced emotional responsiveness
◦ Depressive symptoms
◦ Behavioural disinhibition (particularly with involvement of orbitofrontal circuitry)
● Clinical pearls
▪ The ATR connects anterior and medial thalamic nuclei with several cortical regions, including the medial prefrontal cortex, orbitofrontal cortex, and limbic-associated cortical regions.
▪ Alongside frontostriatal fibres, the ATR contributes to broader frontostriatopallidothalamocortical (FSPTC) loops involved in motivation, executive function, behavioural control, and affective regulation.
▪ The ATR travels through the anterior limb of the internal capsule, explaining why anterior limb lesions can produce behavioural, affective, and executive symptoms despite sparing primary motor pathways.
▪ ATR lesions should be interpreted in the context of broader network disruption:
◦ Symptoms may resemble other frontal-subcortical circuit disorders rather than reflecting a single isolated cognitive deficit.
◦ Clinical relevance is greater with bilateral involvement, extensive lesions, or associated disruption of other frontal-subcortical pathways.
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.