title: Changes in the activity of the cerebral cortex relate to postural response modification when warned of a perturbation.
abstract: OBJECTIVE
  To determine whether the cerebral cortex contributes to modifying upcoming postural responses to external perturbations when provided with prior warning of the perturbation.
  
  
  METHODS
  Electroencephalographic (EEG) potentials were recorded from 12 healthy human subjects (21-32 years of age) before perturbing their balance with backward translations of a platform under their feet. The subjects responded with and without a visual cue that warned them 2s before the perturbation (the Cue and No Cue conditions, respectively).
  
  
  RESULTS
  Contingent negative variation (CNV) was evident before perturbation onset in only the Cue condition. In the Cue condition, the subjects also produced smaller center of pressure (CoP) displacements than in the No Cue condition. The cue-related difference in the subjects' CNV potentials correlated with the cue-related difference in their CoP displacements. No significant associations existed among the CNV potentials and any cue-related postural adjustments made before the perturbation.
  
  
  CONCLUSIONS
  Cortical activity before an externally triggered perturbation associates with modifications of the ensuing postural response.
  
  
  CONCLUSIONS
  This is the first study to demonstrate a cortical correlate for changes in central postural set that modify externally triggered postural responses based on anticipation.
authors.affiliation: Neurological Sciences Institute, Oregon Health and Science University, Beaverton, OR, USA. JJacobs@uvm.edu
authors.forename: Jesse V
authors.initials: JV
authors.lastname: Jacobs
authors.forename: Katsuo
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Hidehito
authors.initials: H
authors.lastname: Tomita
authors.forename: Naoe
authors.initials: N
authors.lastname: Furune
authors.forename: Kenji
authors.initials: K
authors.lastname: Kunita
authors.forename: Fay B
authors.initials: FB
authors.lastname: Horak
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002540:Cerebral Cortex / Q000502:physiology*; D003265:Contingent Negative Variation / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D004585:Electrooculography / Q000379:methods; D005246:Feedback / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011312:Pressure; D011930:Reaction Time; D013997:Time Factors; D014836:Volition