title: The neural basis of age-related changes in motor imagery of gait: an fMRI study.
abstract: BACKGROUND
  Aging is often associated with modifications of gait. Recent studies have revealed a strong relationship between gait and executive functions in healthy and pathological aging. We hypothesized that modification of gait due to aging may be related to changes in frontal lobe function.
  
  
  METHODS
  Fourteen younger (27.0±3.6 years) and 14 older healthy adults (66.0±3.5 years) performed a motor imagery task of gait as well as a matched visual imagery task. Task difficulty was modulated to investigate differential activation for precise control of gait. Task performance was assessed by recording motor imagery latencies, eye movements, and electromyography during functional magnetic resonance imaging scanning.
  
  
  RESULTS
  Our results showed that both healthy older and young adults recruited a network of brain regions comprising the bilateral supplementary motor cortex and primary motor cortex, right prefrontal cortex, and cerebellum, during motor imagery of gait. We observed an age-related increase in brain activity in the right supplementary motor area (BA6), the right orbitofrontal cortex (BA11), and the left dorsolateral frontal cortex (BA10). Activity in the left hippocampus was significantly modulated by task difficulty in the elderly participants. Executive functioning correlated with magnitude of increases in right primary motor cortex (BA4) during the motor imagery task.
  
  
  CONCLUSIONS
  Besides demonstrating a general overlap in brain regions recruited in young and older participants, this study shows age-related changes in cerebral activation during mental imagery of gait. Our results underscore the importance of executive function (dorsolateral frontal cortex) and spatial navigation or memory function (hippocampus) in gait control in elderly individuals.
authors.affiliation: Department of Neurology, Geneva University Hospitals and Faculty of Medicine, University of Geneva, Switzerland. gilles.allali@hcuge.ch.
authors.forename: Gilles
authors.initials: G
authors.lastname: Allali
authors.forename: Marian
authors.initials: M
authors.lastname: van der Meulen
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, UPRES EA 4638, UNAM, Angers University Hospital, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Beauchet
authors.affiliation: Brain & Behaviour Laboratory, Swiss Center for Affective Sciences and Geneva Neuroscience Center, University of Geneva, Switzerland.
authors.forename: Sebastian W
authors.initials: SW
authors.lastname: Rieger
authors.forename: Patrik
authors.initials: P
authors.lastname: Vuilleumier
authors.affiliation: Department of Neurology, Geneva University Hospitals and Faculty of Medicine, University of Geneva, Switzerland.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Assal
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D004576:Electromyography; D056344:Executive Function / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D059907:Functional Neuroimaging; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000503:physiopathology* / Q000523:psychology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000503:physiopathology; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: Aging; Gait; Mental imagery; Neuroimaging.