Dopaminergic Modulation of Lexical-Semantics
The influence of the basal ganglia and dopamine on language is not clearly understood. Studies of individuals with vascular striatal lesions or Parkinson’s disease may provide insight regarding possible subcortical language functions and the dopaminergic modulation of language. Evidence is provided that basal ganglia dysfunction is associated with abnormal semantic processing as shown through lexical ambiguity priming which provides a means of examining exhaustive meaning activation and controlled meaning selection. Further, lexical ambiguity processing appears to be modulated by dopamine in healthy individuals and individuals with Parkinson’s. The role of dopamine is also considered in the context of word learning and aphasia rehabilitation. Preliminary evidence will be provided that dexamphetamine enhances new word learning in healthy individuals and improves recovery of naming in aphasia rehabilitation. Possible mechanisms underlying these effects will be discussed.