A COMPARISON BETWEEN ELECTRIC SOURCE LOCALIZATION AND FMRI DURING SOMATOSENSORY STIMULATION

The present study investigates the electric source localisation of som atosensory evoked potentials (SEPs) using high-resolution EEG (61 scal p electrodes) considering the individual brain morphology as obtained from magnetic resonance images (MRI). A comparison with the activation maps in fMRI under the same somatosensory stimulation paradigm was do ne. The somatosensory evoked potentials (SEPs) to electrical stimulati on of the right median nerve were collected from the scalp of 8 health y right-handed subjects. The source reconstruction for the 20 ms SEP c omponent was performed by using a single moving dipole model as a sour ce model and a spherical three-shell model as a head model, In 6 of th e subjects fMRI was performed using the same electric stimulation of t he right median nerve. The source location of the 20 ms SEP component was found to be within the postcentral gyrus. The fMRI activation maps were also located in the postcentral gyrus when using the same somato sensory stimulation paradigm, The appropriateness of using high-resolu tion EEG and fMRI in the functional localisation of the primary somato sensory cortex is discussed. (C) 1998 Elsevier Science Ireland Ltd.