[Depth EEG and evoked potentials using an intravascular catheter electrode in the baboon]

Obtaining an intracranial EEG, as well as a depth recording of the somatosensory evoked potentials, via a vascular approach are described. Experimentally, a directable microcatheter was placed in the middle cerebral artery of baboons. Using the catheter guide wire as electrode, intracranial electrical activity was recorded from within the cerebral vessels. Significantly, depth recordings of the SEP showed waves of thalamic origin not present in surface recordings. Advantages of this method over surface recordings are the greater gain of information possible and, over other techniques of depth recording, the comparibly lesser invasiveness.