title: The influence of dopamine on semantic activation in Parkinson's disease: evidence from a multipriming task.
abstract: Research has suggested that semantic processing deficits in Parkinson's disease (PD) are related to striatal dopamine deficiency. As an investigation of the influence of dopamine on semantic activation in PD, 7 participants with PD performed a lexical-decision task when on and off levodopa medication. Seven healthy controls matched to the participants with PD in terms of sex, age, and education also participated in the study. By use of a multipriming paradigm, whereby 2 prime words were presented prior to the target word, semantic priming effects were measured across stimulus onset asynchronies (SOAs) of 250 ms and 1,200 ms. The results revealed a similar pattern of priming across SOAs for the control group and the PD participants on medication. In contrast, within-group comparisons revealed that automatic semantic activation was compromised in PD participants when off medication. The implications of these results for the neuromodulatory influence of dopamine on semantic processing in PD are discussed.
authors.affiliation: Centre for Research in Language Processing and Linguistics, University of Queensland, and Department of Neurosciences, Princess Alexandra Hospital, Brisbane, QLD, Australia. a.angwin@uq.edu.au
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Angwin
authors.forename: David A
authors.initials: DA
authors.lastname: Copland
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Chenery
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Murdoch
authors.forename: Peter A
authors.initials: PA
authors.lastname: Silburn
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D004298:Dopamine / Q000502:physiology*; D015259:Dopamine Agents / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D010153:Paired-Associate Learning / Q000187:drug effects / Q000502:physiology*; D010300:Parkinson Disease / Q000188:drug therapy / Q000503:physiopathology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology*; D012660:Semantics; D013997:Time Factors
chemical_list: D015259:Dopamine Agents; D007980:Levodopa; D004298:Dopamine