Probabilistic learning and reversal deficits in patients with Parkinson's disease or frontal or temporal lobe lesions: possible adverse effects of dopaminergic medication

Neuropsychologia. 2000;38(5):596-612. doi: 10.1016/s0028-3932(99)00103-7.


Three groups of patients with Parkinson's disease (PD) - mild, unmedicated (UPD), mild, medicated (MPD) and severe, medicated (SPD) - and patients with lesions of the frontal lobe (FLL) or temporal lobe (TLL) were compared with matched controls on the learning and reversal of probabilistic and two-pair concurrent colour discriminations. Both of the cortical lesion groups showed reversal deficits, with no increase in perseverative responding. The UPD group, although impaired on a spatial recognition task, showed intact discrimination learning and reversal; the MPD and SPD patients showed non-perseverative reversal impairments on both reversal tasks. Two hypotheses - based on disease severity and possible deleterious effects of medication - are offered to explain the reversal impairments of the PD patients and the results are discussed in terms of the role of dopamine in reward-based learning.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antiparkinson Agents / adverse effects*
  • Antiparkinson Agents / therapeutic use
  • Discrimination, Psychological / physiology
  • Epilepsy / surgery
  • Female
  • Frontal Lobe / physiology*
  • Frontal Lobe / surgery
  • Humans
  • Learning Disabilities / psychology*
  • Levodopa / adverse effects*
  • Levodopa / therapeutic use
  • Male
  • Models, Statistical
  • Neostriatum / pathology
  • Parkinson Disease / drug therapy
  • Parkinson Disease / psychology*
  • Pattern Recognition, Visual / physiology
  • Reversal Learning / physiology*
  • Space Perception / physiology
  • Temporal Lobe / physiology*
  • Temporal Lobe / surgery
  • Visual Perception / physiology


  • Antiparkinson Agents
  • Levodopa