Wavelet coherence of EEG signals for a visual oddball task

  • Authors:

  • Yahya T. Qassim;Tim R. H. Cutmore;Daniel A. James;David D. Rowlands

  • Affiliations:

  • Centre of Wireless Monitoring and Applications, Griffith University, 170 Kessels Road, Nathan, Brisbane, QLD 4111, Australia;School of Psychology, Griffith University, Mt. Gravatt Campus, Kessels Road, Brisbane, QLD 4111, Australia;Centre of Wireless Monitoring and Applications, Griffith University, 170 Kessels Road, Nathan, Brisbane, QLD 4111, Australia;Centre of Wireless Monitoring and Applications, Griffith University, 170 Kessels Road, Nathan, Brisbane, QLD 4111, Australia

  • Venue:
  • Computers in Biology and Medicine
  • Year:
  • 2013

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Abstract

Neural co-activation in frontal and central cortex was examined during a visual oddball task using wavelet coherence. EEG was recorded during a visual oddball task, presented to 12 participants with a random mix of 15% oddball targets and 85% frequent non-target letters over 265 trials. Wavelet coherence of individual trials was shown to distinguish frequent and oddball trials. Averaged wavelet coherence showed significant differences: oddball targets showed higher delta-theta activity whereas frequent background stimuli showed higher gamma activity. Increased gamma coherence appeared to be related to expectation of the targets with our analysis showing an R^2 of 0.935 for the relationship between averaged sections of gamma coherence and the number of intervening (frequent) trials since the last oddball.