Pattern recognition in biomagnetic signals by spatio-temporal correlation and application to the localisation of propagating neuronal activity.

A combined correlation analysis of temporal and spatial patterns in a biomagnetic multichannel recording is proposed to extract patterns of transient, randomly repetitive physiological events from biomagnetic data sets with a low signal-to-noise ratio. This method is especially sensitive in the differentiation of signals from different source propagation pathways. The recognition and subsequent averaging of spike events in the MEG of an epileptic patient by this method is shown to provide an essential improvement in the signal-to-noise ratio. The source localisation from the averaged data showed electrical activity which propagated from the primary epileptogenic focus to distant parts of the brain.