title: Cortical involvement in a gait-related imagery task: comparison between Parkinson's disease and normal aging.
abstract: OBJECTIVE
  We employed imaginary tasks to investigate the neurophysiology of gait in patients with Parkinson's disease (PD) using functional magnetic resonance imaging (fMRI).
  
  
  METHODS
  Cortical activation of gait-related imagery was explored in 13 PD patients, 13 age-matched controls (Old), and 14 young volunteers (Young) using fMRI. The tasks included gait initiation, stepping over an obstacle and gait termination using an event-related design. Subjects watched a video clip showing an actor walking and imagined the walking process.
  
  
  RESULTS
  At gait initiation, no significant difference could be found between PD and the Old controls. Activation in the visual related areas in the Old subjects was increased compared to the Young subjects. While imagining stepping over obstacles, the right dorsal premotor area (PMd), precentral, right inferior parietal lobule, and bilateral precuneus were more activated in PD compared to the Old. An extensive network of bilateral SMA, PMd, posterior parietal lobe and visual association areas was activated in the Old versus the Young subjects. At gait termination, visual related areas were noted when PD was compared to the Old. In contrast, increased activation in bilateral pre-SMA, PMd, ventral premotor area, precentral, posterior parietal lobes and visual association areas were activated in the Old when compared to the Young.
  
  
  CONCLUSIONS
  Our study provides image based evidence for gait disturbance in PD patients and during normal aging. The compensatory cortical mechanism in the findings could be a background resource for further therapeutic interventions.
authors.affiliation: Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taiwan.
authors.forename: Yau-Yau
authors.initials: YY
authors.lastname: Wai
authors.forename: Jiun-Jie
authors.initials: JJ
authors.lastname: Wang
authors.forename: Yi-Hsin
authors.initials: YH
authors.lastname: Weng
authors.forename: Wey-Yil
authors.initials: WY
authors.lastname: Lin
authors.forename: Hon-Kwong
authors.initials: HK
authors.lastname: Ma
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
authors.forename: Yung-Liang
authors.initials: YL
authors.lastname: Wan
authors.forename: Chi-Hong
authors.initials: CH
authors.lastname: Wang
mesh_terms: D000368:Aged; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000209:etiology* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007092:Imagination / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010300:Parkinson Disease / Q000150:complications*; D010775:Photic Stimulation; D013624:Taiwan
chemical_list: D010100:Oxygen