title: Frequency characteristics of cortical activity associated with perturbations to upright stability.
abstract: Cortical evoked potentials are evident in the control of whole-body balance reactions in response to transient instability. The focus of this work is to continue to advance understanding of the potential cortical contributions to bipedal balance control. Temporally unpredictable postural perturbations evoke a negative potential (N1), which has drawn parallels to error-related negativity (ERN) as well as visual and auditory evoked N1 responses. The mechanism underlying the generation of event-related potentials (ERPs) has been a matter of debate for the past few decades. While the evoked model proposes that ERPs are generated by the addition of fixed latency and fixed polarity responses, the phase reorganization model suggests that ERPs are the result of stimulus-induced phase reorganization of the ongoing oscillations. Previous studies have suggested phase reorganization as a possible mechanism in auditory N1, visual N1 and error-related negativity (ERN). The purpose of the current study was to explore the frequency characteristics of the cortical responses to whole-body balance perturbations. Perturbations were evoked using a lean and release protocol. The results revealed a significant power increase and phase-locking of delta, theta, alpha, and beta band activity during perturbation-evoked N1. This may suggest that the stimulus-induced phase reorganization of the ongoing electroencephalographic (EEG) activity could account for the features of cortical ERPs in response to perturbation of upright stability.
authors: Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
authors: Jessy Parokaran
authors: JP
authors: Varghese
authors: Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
authors: Amanda
authors: A
authors: Marlin
authors: Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
authors: Kit B
authors: KB
authors: Beyer
authors: Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
authors: William R
authors: WR
authors: Staines
authors: Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada.
authors: George
authors: G
authors: Mochizuki
authors: Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada; Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada. Electronic address: wmcilroy@uwaterloo.ca.
authors: William E
authors: WE
authors: McIlroy
mesh_terms: D000328:Adult; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D055815:Young Adult
keywords: Balance; Electroencephalography; Event-related potential; Perturbation-evoked potential; Phase resetting