HIGH-RESOLUTION EEG - 124-CHANNEL RECORDING, SPATIAL DEBLURRING AND MRI INTEGRATION METHODS

This paper describes a method for increasing the spatial detail of the EEG and for integrating physiological data with anatomical models bas ed on magnetic resonance images (MRIs). This method includes technique s to efficiently record EEG data from up to 124 channels, to measure 3 -D electrode positions for alignment with MRI-derived head models, and to estimate potentials near the outer convexity of the cortex using a spatial deblurring technique which uses a realistic model of the stru cture of the head and which makes no assumptions about the number or t ype of generator sources. The validity of this approach has been initi ally tested by comparing estimated cortical potentials with those meas ured with subdural grid recordings from two neurosurgical patients. Th e method is illustrated with somatosensory steady-state evoked potenti al data recorded from 5 healthy subjects. Results suggest that deblurr ed 124-channel topographic maps, registered with a subject's MRI and r endered in 3 dimensions, provide better spatial detail than has hereto fore been obtained with scalp EEG recordings. The results also suggest that the potential for EEG as a functional neuroimaging modality has yet to be fully realized.