A dynamic approach to epileptic seizure anticipation, combining neuro-dynamic analysis of brain activity with pheno-dynamic analysis of subjective experience, can guide and determine each other. This method consolidates the foundations for a cognitive, non-pharmacological therapy for epilepsy. The neuro-phenomenological co-determination demonstrated through this example offers new insight into the gap between subjective experience and neurophysiological activity.
Surface EEG recordings from 10 patients, previously studied with intracerebral electrodes, were analyzed to bridge the gap between depth and scalp measures of conscious report. Pooling trials across participants, event-related potentials showed a significant positive deflection for Seen compared to Unseen targets at frontal sites 350-500 milliseconds after the target, consistent with a P3b component. Time-frequency analysis revealed pretarget beta/gamma power modulations at frontal electrodes and post-target increased oscillatory activity at occipital sites. Clustering of intracerebral data identified two patterns: an early Visual cluster (120-340 ms) and a later Accumulation cluster (230-490 ms). Ridge regression showed the Accumulation cluster contributed more to predicting scalp ERPs, highlighting the greater role of late integrative mechanisms over early sensory processes in conscious experience.
Using a new rodent model of reversible brain anoxia with continuous electrocorticographic (ECoG) and intracellular recordings, the authors tracked neocortical dynamics from oxygen deprivation through recovery. Oxygen loss caused an early surge of beta-gamma activity with rhythmic membrane depolarizations in pyramidal neurons, followed by low-frequency activity declining to isoelectric levels. During the isoelectric state, a massive depolarizing shift produced a large triphasic ECoG wave known as the "wave-of-death" (WoD). If re-oxygenation occurred within 2–3.5 minutes, this anoxic depolarization reversed. The subsequent slow repolarization generated a second ECoG wave termed "wave-of-resuscitation," marking recovery of pre-anoxic activity. The WoD is not a biomarker of irremediable death; the new wave may predict successful recovery.