Dopaminergic modulation of visual-spatial working memory in Parkinson's disease.
Visual-spatial working memory (WM) impairment is frequently associated with the early stage of Parkinson's disease (PD). The aim of this study was to evaluate the performance of a group of PD patients in visual-spatial and visual-object WM tasks and to investigate the effect of administering the dopaminergic agonist apomorphine (experiment 1) or the dopamine precursor L-dopa (experiment 2) on the performance of tests assessing these functions. To study WM processes, the PD patients and age-matched normal controls were given an n-back task paradigm. In both experiments, the PD patients were submitted to two evaluations: one after a 12-hour therapy washout and the other 15 min after a subcutaneous infusion of apomorphine (average 0.04 mg/kg) or 20/30 min after L-dopa intake (200 mg p.o.). The apomorphine infusion had a worsening effect on reaction times in both visual-spatial and visual-object WM tasks, but it did not influence performance accuracy. Instead, L-dopa administration had a ameliorative effect on accuracy and reaction times in both visual-spatial and visual-object tasks. These results highlight the role of dopamine in the modulation of the WM function in PD patients.
Costa
Alberto
A
IRCCS, Fondazione Santa Lucia, Università di Roma Tor Vergata, Italia. memolab@hsantalucia.it
Peppe
Antonella
A
Dell'Agnello
Grazia
G
Carlesimo
Giovanni Augusto
GA
Murri
Luigi
L
Bonuccelli
Ubaldo
U
Caltagirone
Carlo
C
D001058:Apomorphine / Q000494:pharmacology; D003071:Cognition / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology; D005260:Female; D006801:Humans; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D008568:Memory / Q000187:drug effects*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000523:psychology*; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000187:drug effects*
D015259:Dopamine Agents; D018491:Dopamine Agonists; D007980:Levodopa; D001058:Apomorphine; D004298:Dopamine