title: Novelty processing and memory formation in Parkinson's disease.
abstract: BACKGROUND
  Parkinson's disease (PD) is characterized by a degeneration of nigrostriatal dopaminergic cells, resulting in dopamine depletion. This depletion is counteracted through dopamine replacement therapy (DRT). Dopamine has been suggested to affect novelty processing and memory, which suggests that these processes are also implicated in PD and that DRT could affect them.
  
  
  OBJECTIVE
  To investigate word learning and novelty processing in patients with PD as indexed by the P2 and P3 event-related potential components, and the role of DRT in these processes.
  
  
  METHODS
  21 patients with PD and 21 matched healthy controls were included. Patients with PD were tested on and off DRT in two sessions in a counterbalanced design, and healthy controls were tested twice without intervention. Electroencephalogram (EEG) was measured while participants performed a word learning Von Restorff task.
  
  
  RESULTS
  Healthy controls showed the typical Von Restorff effect, with better memory for words that were presented in novel fonts, than for words presented in standard font. Surprisingly, this effect was reversed in the patients with PD. In line with the behavioral findings, the P3 was larger for novel than for standard font words in healthy controls, but not in patients with PD. For both groups the P2 and P3 event-related components were larger for recalled versus forgotten words. DRT did not affect these processes.
  
  
  CONCLUSIONS
  Learning of novel information is compromised in patients with PD. Likewise, the P2 and P3 components that predict successful memory encoding are reduced in PD patients. This was true both on and off DRT, suggesting that these findings reflect abnormalities in learning and memory in PD that are not resolved by dopaminergic medication.
authors: Department of Cognitive Psychology, VU University, Amsterdam, The Netherlands. Electronic address: j.schomaker@vu.nl.
authors: J
authors: J
authors: Schomaker
authors: Department of Neurology, VU University Medical Center (VUMC), Amsterdam, The Netherlands; Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands.
authors: H W
authors: HW
authors: Berendse
authors: Department of Neurology, VU University Medical Center (VUMC), Amsterdam, The Netherlands.
authors: E M J
authors: EM
authors: Foncke
authors: Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands; Department of Anatomy and Neurosciences, VUMC, Amsterdam, The Netherlands; Netherlands Institute for Neuroscience, Amsterdam, The Netherlands.
authors: Y D
authors: YD
authors: van der Werf
authors: Neuroscience Campus Amsterdam, VU/VUMC, Amsterdam, The Netherlands; Department of Anatomy and Neurosciences, VUMC, Amsterdam, The Netherlands; Department of Psychiatry, VUMC, Amsterdam, The Netherlands.
authors: O A
authors: OA
authors: van den Heuvel
authors: Department of Cognitive Psychology, VU University, Amsterdam, The Netherlands.
authors: J
authors: J
authors: Theeuwes
authors: Department of Cognitive Psychology, VU University, Amsterdam, The Netherlands.
authors: M
authors: M
authors: Meeter
mesh_terms: D000161:Acoustic Stimulation; D000368:Aged; D000704:Analysis of Variance; D001931:Brain Mapping; D016022:Case-Control Studies; D015259:Dopamine Agents / Q000627:therapeutic use; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy; D014706:Verbal Learning / Q000502:physiology*; D014825:Vocabulary
chemical_list: D015259:Dopamine Agents
keywords: Dopamine; Learning; Memory; Novelty processing; Parkinson׳s disease; Von Restorff effect