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Article
Assessing Time-Dependent Association between Scalp EEG and Muscle Activation: A Functional Random-Effects Model Approach
Journal of Neuroscience Methods (2009)
  • Xiao-Feng Wang, Cleveland Clinic Lerner Research Institute
  • Qi Yang, Cleveland Clinic Lerner Research Institute
  • Zhaozhi Fan, Memorial University of Newfoundland
  • Chang-Kai Sun
  • Guang H Yue, Cleveland Clinic Lerner Research Institute
Abstract
This study investigates time-dependent associations between source strength estimated from high-density scalp electroencephalogram (EEG) and force of voluntary handgrip contraction at different intensity levels. We first estimate source strength from raw EEG signals collected during voluntary muscle contractions at different levels and then propose a functional random-effects model approach in which both functional fixed effects and functional random-effects are considered for the data. Two estimation procedures for the functional model are discussed. The first estimation procedure is a two-step method which involves no iterations. It can flexibly use different smoothing methods and smoothing parameters. The second estimation procedure benefits from the connection between linear mixed models and regression splines and can be fitted using existing software. Functional ANOVA is then suggested to assess the experimental effects from the functional point of view. The statistical analysis shows that the time-dependent source strength function exhibits a nonlinear feature, where a bump is detected around the force onset time. However, there is the lack of significant variations in source strength on different force levels and different cortical areas. The proposed functional random-effects model procedure can be applied to other types of functional data in neuroscience.
Keywords
  • EEG; Source strength; Fatigue; Muscle activation; Functional data; Functional random-effects model
Disciplines
Publication Date
February, 2009
Citation Information
Xiao-Feng Wang, Qi Yang, Zhaozhi Fan, Chang-Kai Sun, et al.. "Assessing Time-Dependent Association between Scalp EEG and Muscle Activation: A Functional Random-Effects Model Approach" Journal of Neuroscience Methods Vol. 177 Iss. 1 (2009)
Available at: http://works.bepress.com/wang/11/