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Biological Cybernetics

, Volume 79, Issue 5, pp 437–442 | Cite as

Analysis of the electroencephalographic activity during the Necker cube reversals by means of the wavelet transform

  • Ümmühan İşoğlu-Alkaç
  • Canan Başar-Eroğlu
  • Ahmet Ademoğlu
  • Tamer Demiralp
  • Michael Miener
  • Michael Stadler
Article

Abstract.

In previous studies, a perceptual switching related potential was obtained during the observation of a multistable dynamic reversal pattern, where the averaging of the single responses was triggered by subjects pressing a button. The present methodological study aims to increase the signal quality of perceptual switching related potentials considering the dependence of the measurement method on the reaction time of the subject, which may vary significantly during a session, leading to low-amplitude waveform in the averaged event-related-potential (ERP). To overcome this problem in measuring the electrophysiological correlate of an internal event, a pattern selection method based on the wavelet transform (WT) is proposed to choose a subset of single ERPs with more homogenous latencies. Nine subjects observed a Necker cube and were instructed to press the button immediately after perceptual switching. A slow, low-amplitude positive wave with frontocentral amplitude maxima was observed around 250 ms prior to the button press. After the application of a 5 octave WT on single sweeps, the time-frequency coefficients obtained in each octave were averaged across trials. The most dominant feature representing the averaged ERP was the delta (0.5–4 Hz) coefficient occurring between 250 and 125 ms before the button press. By averaging the subset of the single sweeps containing this property, a sharpening and significant amplitude increase of the response peak was observed.

Keywords

Wavelet Transform Response Peak Dominant Feature Pattern Selection Button Press 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Ümmühan İşoğlu-Alkaç
    • 1
  • Canan Başar-Eroğlu
    • 2
  • Ahmet Ademoğlu
    • 3
  • Tamer Demiralp
    • 1
  • Michael Miener
    • 2
  • Michael Stadler
    • 2
  1. 1.Electro-Neuro-Physiology Research and Application Center, University of Istanbul, 34390 Çapa Istanbul, TurkeyTR
  2. 2.Institute of Psychology and Cognition Research and Center for Cognitive Science, University of Bremen, D-28334 Bremen, GermanyDE
  3. 3.Institute of Biomedical Engineering, Boğaziçi University, Bebek Istanbul, 80815 TurkeyTR

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