Mediodorsal nucleus and its multiple cognitive functions

The mediodorsal nucleus of the thalamus (MDT) is one of the largest thalamic nuclei and is a typical association nucleus, participating in several cortico-subcortical networks, primarily those involving the prefrontal cortex.(1-3) Pathologic involvement of the MDT or its cortical connections contributes to the cognitive, emotional, and behavioral manifestations of stroke(4-6); metabolic disorders, such as Wernicke encephalopathy(7); inflammatory disorders, such as multiple sclerosis(8); prion disorders, such as fatal familial insomnia(9) and Creutzfeldt-Jakob disease(10); and neurodegenerative diseases, such as Alzheimer disease,(11) dementia with Lewy bodies,(12) and Parkinson disease.(13) The MDT also participates in the pathophysiology of epilepsy(14,15) and schizophrenia.(16) The following case shows that its involvement affects wide cortical areas and produces disabling symptoms that may not be associated with objective abnormalities in neuropsychometric testing.