Estimation of the spatiotemporal structure of event-related desynchronization and synchronization in magnetoencephalography.
We present a comprehensive methodology for identifying cerebral areas involved in event-related changes of electromagnetic activity of the human brain, and also for tracing the temporal evolution of this activity. Information from pre- and peristimulus time intervals--in terms of event-related synchronization (ERS) and desynchronization (ERD) of the magnetoencephalographic (MEG) signal--was directly incorporated in the relevant test statistics. For the individual steps of the analysis, we used particular estimations of the time-frequency distribution of the energy along with particular error control methods, that is, short-time Fourier transform and false-discovery rate at the sensor level and multitapers and familywise error rate at the source level. This procedure was applied to two types of group-level tests, a within-condition test and a between-conditions test. The performance of the proposed methodology is assessed by (1) analyzing the event-related brain activity from two experimental conditions of an auditory MEG experiment--passive listening to a sequence of frequency-modulated sweeps and their active categorization with respect to the direction of frequency modulation, and (2) comparing the findings with those obtained with a widely used cluster-based analysis.
Faculty of Physics, Institute of Experimental Physics, Department of Biomedical Physics, University of Warsaw, ul. Hoża 69, 00-681 Warszawa, Poland. jarekz@fuw.edu.pl
J
J
Zygierewicz
C
C
Sielużycki
N
N
Zacharias
P
P
Suffczyński
P
P
Kordowski
H
H
Scheich
P J
PJ
Durka
R
R
König
D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception; D016000:Cluster Analysis; D003344:Cortical Synchronization; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials; D005189:False Positive Reactions; D005260:Female; D005583:Fourier Analysis; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results