title: Brain activity during complex imagined gait tasks in Parkinson disease.
abstract: OBJECTIVE
  Motor imagery during functional magnetic resonance imaging (fMRI) allows assessment of brain activity during tasks, like walking, that cannot be completed in an MRI scanner. We used gait imagery to assess the neural pathophysiology of locomotion in Parkinson disease (PD).
  
  
  METHODS
  Brain activity was measured in five locomotor regions (supplementary motor area (SMA), globus pallidus (GP), putamen, mesencephalic locomotor region, cerebellar locomotor region) during simple (forward) and complex (backward, turning) gait imagery. Brain activity was correlated to overground walking velocity.
  
  
  RESULTS
  Across tasks, PD exhibited reduced activity in the globus pallidus compared to controls. People with PD, but not controls, exhibited more activity in the SMA during imagined turning compared to forward or backward walking. In PD, walking speed was correlated to brain activity in several regions.
  
  
  CONCLUSIONS
  Altered SMA activity in PD during imagined turning may represent compensatory neural adaptations during complex gait. The lowered activity and positive correlation to locomotor function in GP suggests reduced activity in this region may relate to locomotor dysfunction.
  
  
  CONCLUSIONS
  This study elucidates changes in neural activity during gait in PD, underscoring the importance of testing simple and complex tasks. Results support a positive relationship between activity in locomotor regions and walking ability.
authors.affiliation: Program in Physical Therapy, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States. Electronic address: petersond@wusm.wustl.edu.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Peterson
authors.affiliation: Program in Physical Therapy, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States; Department of Neurology, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States. Electronic address: pickettk@wusm.wustl.edu.
authors.forename: Kristen A
authors.initials: KA
authors.lastname: Pickett
authors.affiliation: Program in Physical Therapy, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States. Electronic address: duncanr@wusm.wustl.edu.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Duncan
authors.affiliation: Program in Physical Therapy, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States; Department of Neurology, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States; Department of Neurobiology, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States; Department of Radiology, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States; Program in Occupational Therapy, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States. Electronic address: joel@npg.wustl.edu.
authors.forename: Joel S
authors.initials: JS
authors.lastname: Perlmutter
authors.affiliation: Program in Physical Therapy, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States; Department of Neurology, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States; Department of Neurobiology, Washington University in St. Louis, 660 S. Euclid, St. Louis, MO 63110, United States. Electronic address: earhartg@wusm.wustl.edu.
authors.forename: Gammon M
authors.initials: GM
authors.lastname: Earhart
mesh_terms: D000368:Aged; D002531:Cerebellum / Q000503:physiopathology*; D005684:Gait / Q000502:physiology; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology*; D005917:Globus Pallidus / Q000503:physiopathology*; D006801:Humans; D007092:Imagination; D008124:Locomotion; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology*; D016138:Walking / Q000502:physiology
keywords: Gait; Imagery; Parkinson disease; fMRI