A Time-Variant Processing Approach for the Analysis of Alpha and Gamma MEG Oscillations During Flicker Stimulus Generated Entrainment

• Published in: IEEE transactions on biomedical engineering Vol. 58; no. 11; pp. 3069 - 3077
• Main Authors: Wacker, Matthias, Galicki, Miroslav, Putsche, Peter, Milde, Thomas, Schwab, Karin, Haueisen, Jens, Ligges, Carolin, Witte, Herbert
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.11.2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adult; Algorithms; Biological and medical sciences; Computerized, statistical medical data processing and models in biomedicine; Electrodiagnosis. Electric activity recording; Electroencephalogram (EEG); Electroencephalography; Electroencephalography Phase Synchronization - physiology; Electrooculography; Female; Gabor transform; Humans; Indexes; Investigative techniques, diagnostic techniques (general aspects); Magnetoencephalogram (MEG); Magnetoencephalography - methods; Male; Medical management aid. Diagnosis aid; Medical sciences; Multivariate Analysis; Nervous system; Oscillators; Photic Stimulation; Signal Processing, Computer-Assisted; Time frequency analysis; time-variant autoregressive model; Transforms; Visual Cortex - physiology; Gabor transform; Magnetoencephalography; Gabor transformation; Electrophysiology; Electroencephalography; Autoregressive model; Flicker; Electrodiagnosis; time-variant autoregressive model; Electroencephalogram (EEG); Time varying processing; Magnetoencephalogram (MEG); Biomedical engineering
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2011.2160640

Repetitive flicker stimulation (photic driving) offers the possibility to study the properties and coupling characteristics of stimulation-sensitive neuronal oscillators by means of the MEG/EEG analysis. With flicker frequencies in the region of the individual alpha band frequency, the dynamics of the entrainment process of the alpha oscillation, as well as the dynamics of the accompanying gamma oscillations and the coupling between the oscillations, are investigated by means of an appropriate combination of time-variant analysis methods. The Hilbert and the Gabor transformation reveal time-variant properties (frequency entrainment, phase locking, and n:m synchronization) of the entrainment process in the whole frequency range. Additionally, time-variant partial directed coherence is applied to identify ocular saccadic interferences and to study the directed information transfer between the recording sites of the simultaneously derived MEG/EEG data during the entrainment. The MEG data is the focus of this methodological study as the entrainment effects of the alpha oscillation are stronger in MEG than in the EEG. The occipital brain region (visual cortex) was mainly investigated and the dynamics of the alpha entrainment quantified. It can be shown that at the beginning of this entrainment, a transient, strongly phase-locked "40-Hz" gamma oscillation occurs.