Intraparenchymatous ponto-mesencephalic field distribution of brain-stem auditory evoked potentials in man

Brain-stem auditory evoked potentials (BAEPs) were recorded simultaneously from scalp electrodes and intraparenchymatous sites along a ponto-mesencephalic stereotactic penetration path in a patient with the unique condition of a brain-stem tumour which therapeutically necessitated radionuclide implantation but did not grossly affect scalp BAEPs. The data suggest major contributions to scalp peak III from the pons ipsilateral to the stimulated ear, to peak IV from both ipsi- and contralateral sources, and to peak V mainly from contralateral, more rostral sites. Some local activities evidently did not project to the scalp.