Dopaminergic modulation of visual-spatial working memory in Parkinson's disease

Dement Geriatr Cogn Disord. 2003;15(2):55-66. doi: 10.1159/000067968.


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.

Publication types

  • Comparative Study

MeSH terms

  • Apomorphine / pharmacology
  • Cognition / drug effects
  • Dopamine / metabolism
  • Dopamine Agents / pharmacology*
  • Dopamine Agonists / pharmacology
  • Female
  • Humans
  • Levodopa / pharmacology
  • Male
  • Memory / drug effects*
  • Middle Aged
  • Neuropsychological Tests
  • Parkinson Disease / psychology*
  • Task Performance and Analysis
  • Visual Perception / drug effects*


  • Dopamine Agents
  • Dopamine Agonists
  • Levodopa
  • Apomorphine
  • Dopamine