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Abstract Objectives We will demonstrate that FIRDA (frontal intermittent rhythmic delta activity)—otherwise related to systemic disorders and encephalopathy—has a role as an epileptic biomarker of deep‐seated midline SOZ. Its abolishment following SEEG‐guided radiofrequency of such SOZ correlates with clinical improvement suggesting its role as a noninvasive biomarker of otherwise inaccessible SOZs. Methods We report the case of AK who was admitted with “psychiatric and gastrointestinal complaints.” AK's complaints were further associated with FIRDA during VEEG. His previous refractoriness to AEDs, the clinico‐electroencephalographic correlation, MRI showing bilateral hippocampal atrophy (more to the left) and severe memory deficits, prompted us to suggest a left temporo‐mesial SOZ, for which SEEG was done. Dual SEEG and scalp electrodes were used primarily for diagnostic purposes but taking into account an option for a therapeutic action by RF ablation. Results The dual array demonstrated a clear association between left hippocampal high voltage spikes and HFOs on SEEG recordings with FIRDA on concomitant scalp EEG parallel to behavioral changes, as suspected in our preliminary hypothesis. A further RF ablation eliminated the epileptiform activity (Spikes, HFOs, and FIRDA) followed by clinical improvement. Significance This is the first report showing the clinical significance of FIRDA associated with behavioral changes as a marker for latent refractory mesial epilepsy. SEEG exploration has the potential to uncover deep sources, which are manifested as FIRDA on scalp EEG. These abnormalities and clinical symptoms can be eliminated by RF ablation.

While the contribution of sharp wave ripples in memory consolidation and decision-making is established in rodent models, our understanding of their role in human memory is incomplete. Here, the authors discuss common methodological challenges in detecting, analyzing, and reporting sharp wave ripples, then they suggest practical solutions to distinguish them from other high-frequency events

Summary: The magnitude of neuronal activation is commonly considered a critical factor for conscious perception of visual content. However, this dogma contrasts with the phenomenon of rapid adaptation, in which the magnitude of neuronal activation drops dramatically in a rapid manner while the visual stimulus and the conscious experience it elicits remain stable. Here, we report that the profiles of multi-site activation patterns and their relational geometry—i.e., the similarity distances between activation patterns, as revealed using intracranial electroencephalographic (iEEG) recordings—are sustained during extended visual stimulation despite the major magnitude decrease. These results are compatible with the hypothesis that conscious perceptual content is associated with the neuronal pattern profiles and their similarity distances, rather than the overall activation magnitude, in human visual cortex.

Though people are easily able to recall items in a category without mentioning a wrong exemplar, the mechanism underlying this ability is unknown. Here, authors use intracranial recordings to show that this ability is likely due to a selective increase in baseline neuronal activity in category-specific regions.