title: Dopamine does not appear to affect mental rotation in Parkinson's disease.
abstract: OBJECTIVE
  Patients with Parkinson's disease (PD) often have deficits with mental rotation (MR). The neuropathological factors underlying these deficits, however, remain to be elucidated. One hypothesis suggests that dopamine depletion in nigro-striatal systems adversely influences MR. Another hypothesis suggests that deterioration of cortical (fronto-temporo-parietal basal ganglia) networks that mediate this function are responsible for this deficit. The goal of this study was to test the dopamine hypothesis by determining if dopamine abstinence negatively influences MR performance.
  
  
  METHODS
  Thirty three non-demented right-handed individuals with PD were assess for their ability to perform a pencil and paper MR test while "on" and "off" dopaminergic medications. Dopamine abstinence followed the typical overnight withdrawal procedures.
  
  
  RESULTS
  No differences in mental rotation abilities were found between "on" and "off" dopaminergic medications.
  
  
  CONCLUSIONS
  These results suggest that other neuropathological factors, such as cortical-basal ganglia neurodegeneration, or dysfunction of other neurotransmitters systems, might account for these cognitive deficits and future research will have to test these alternative hypotheses.
authors.affiliation: Memphis, TN, USA.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Crucian
authors.affiliation: Department of Orthopedics, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Sheyan
authors.initials: S
authors.lastname: Armaghani
authors.affiliation: Department of Internal Medicine, University of Florida, Gainesville, FL, USA.
authors.forename: Avan
authors.initials: A
authors.lastname: Armaghani
authors.affiliation: Middle Tennessee State University, Murfreesboro, TN, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Foster
authors.affiliation: Department of Neurology, University of Florida, Gainesville, FL, USA ; Malcom Randall VA Medical Center, Gainesville, FL, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Burks
authors.affiliation: Private Practice, Wilmington, NC, USA.
authors.forename: Barry
authors.initials: B
authors.lastname: Skoblar
authors.affiliation: Laboratorio LENITEM, IRCCS San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Drago
authors.affiliation: Department of Neurology, University of Florida, Gainesville, FL, USA ; Malcom Randall VA Medical Center, Gainesville, FL, USA.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Heilman
keywords: Cognitive deficits; Dopamine; Mental rotation; Parkinson’s disease; Visual-spatial