High-resolution EEG: Modeling time, space and phase of SEPs following upper limb stimulation

High-resolution electroencephalography (HREEG) includes an elevated spatial sampling of scalp potentials (to 128 channels) and the reduction of head volume conduction effects by surface Laplacian transformation over (un)realistic head models. The HREEG has a high temporal resolution (in ms) and an acceptable spatial resolution (in cm) in the estimation of both radially and tangentially oriented cortical sources. This allows the modeling of short-term cortical responses evoked by median nerve stimulation based on phase-locked somatosensory-evoked potentials (SEPs). Phase-locked SEPs have the whole (ms) temporal resolution of EEG data, compared to the temporal resolution of nonphase-locked EEG oscillatory reactivity (i.e. about 100 ms for alpha rhythm, 8–12 Hz). In this report, the HREEG (128 channels) modeled temporal, spatial and phase-locked features of SEPs during sensorimotor interactions. © 2002 Elsevier Science B.V.