Coherence in depth electrodes during induction of deep anesthesia.

Our aim was to explore time-varying coherence values versus spacing and referencing of electrode contacts in thalamic level from human encephalographic (EEG) data. Data has been acquired during induction of propofol anesthesia until burst-suppression level in scalp EEG. Results are shown from coherence analysis applied to EEG signals from selected depth electrode contacts pair-wise of three subjects. Alpha coherence is the most prominent behavior in all channel pairs. It is persistent throughout the time period followed and in coherence calculated between bipolar derivations in depth electrodes.