The Contributions of Intracerebral Currents to the EEG and Evoked Potentials

Scalp and cortical potentials due to implanted, dipole current sources were measured in the monkey. A four region spherical model of the head was developed and scalp potentials due to theoretical radial dipoles were computed and compared with experimental results. Dipole source locations were chosen to correspond to points along the somatosensory projection pathways to permit comparison of findings with clinical cortical and scalp evoked potential records. Data yielded by the theoretical head model compare well with those obtained experimentally. The results suggest that depth cerebral bioelectric sources can contribute to scalp recorded activity when averaging techniques are used.