title: The role of learned irrelevance in attentional set-shifting impairments in Parkinson's disease.
abstract: In this study, the cognitive and neurochemical factors underlying learned irrelevance, one of the mechanisms thought to be responsible for attentional set-shifting deficits in Parkinson's disease (PD), were investigated. In a visual discrimination learning task, the extent to which a target dimension was irrelevant prior to an extra-dimensional shift was varied. Twenty patients with PD and 22 healthy participants performed the task twice, with patients tested on and off L-dopa. The patients made more errors than control participants in the condition in which the target dimension was completely irrelevant prior to the extradimensional shift, but not when it was partially reinforced. Moreover, L-dopa had no effect on the patients' task performance, despite improving their working memory. These results confirm that learned irrelevance is a significant factor in accounting for attentional set-shifting deficits in patients with PD, although unlike other executive impairments in this group, the phenomenon appears to be unrelated to their central dopaminergic deficit.
authors.affiliation: MRC Cognition and Brain Sciences Unit, Cambridge, England. aleksandra.slabosz@mrc-cbu.cam.ac.uk
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Slabosz
authors.forename: Simon J G
authors.initials: SJ
authors.lastname: Lewis
authors.forename: Kamila
authors.initials: K
authors.lastname: Smigasiewicz
authors.forename: Blazej
authors.initials: B
authors.lastname: Szymura
authors.forename: Roger A
authors.initials: RA
authors.lastname: Barker
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Owen
mesh_terms: D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001288:Attention / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000188:drug therapy / Q000523:psychology*
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa; D004298:Dopamine