Estimation of the spatiotemporal structure of event-related desynchronization and synchronization in magnetoencephalography

• Published in: Journal of neuroscience methods 2012-03, Vol.205 (1), p.148-158
• Main Authors: Żygierewicz, J., Sielużycki, C., Zacharias, N., Suffczyński, P., Kordowski, P., Scheich, H., Durka, P.J., König, R.
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Adult; Auditory Perception; Cluster Analysis; Cortical Synchronization; Data Interpretation, Statistical; Dynamic imaging of coherent sources; Electroencephalography; ERD – event-related desynchronization; ERS – event-related synchronization; Evoked Potentials - physiology; Excitatory Postsynaptic Potentials; False Positive Reactions; Female; Fourier Analysis; Functional Laterality - physiology; Humans; IS – inverse solutions; Magnetoencephalography - methods; Male; MEG – magnetoencephalography; Multiple comparison problem; Reproducibility of Results
• ISSN: 0165-0270; 1872-678X
• DOI: 10.1016/j.jneumeth.2011.12.013

► Identification and localization of sources of oscillatory activity in the brain. ► Group-level statistical tests: a within- and a between-conditions test. ► Localization of MEG desynchronization in an auditory experiment. ► Temporal evolution of beta band induced activity across the brain. 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.