Slow oscillations open susceptible time windows for epileptic discharges

Autor: Charles Quairiaux, Shahan Momjian, Laurent Spinelli, Andreas Kleinschmidt, M. Seeck, Pierre Mégevand, Christian Bénar, Serge Vulliemoz, Laurent Sheybani
Přispěvatelé: Geneva University Hospital (HUG), University of Geneva [Switzerland], Institut de Neurosciences des Systèmes (INS), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpitaux Universitaires de Genève (HUG), Swiss National Science Foundation Grants 167836, CRSII5 170873 and 192749, CRS115- 180365 and 163398, ANR-17-HBPR-0005,SCALES,Mesures à plusieurs échelles dans des protocoles cognitifs grâce à des enregistrements simultanés de surface et de profondeur(2017), Université de Genève = University of Geneva (UNIGE)
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Epilepsia
Epilepsia, Wiley, 2021, 62 (10), pp.2357-2371. ⟨10.1111/epi.17020⟩
Epilepsia (2021)
ISSN: 0013-9580
DOI: 10.1111/epi.17020⟩
Popis: Objective: In patients with epilepsy, interictal epileptic discharges are a diag-nostic hallmark of epilepsy and represent abnormal, so- called “irritative” activity that disrupts normal cognitive functions. Despite their clinical relevance, their mechanisms of generation remain poorly understood. It is assumed that brain activity switches abruptly, unpredictably, and supposedly randomly to these epi-leptic transients. We aim to study the period preceding these epileptic discharges, to extract potential proepileptogenic mechanisms supporting their expression.Methods: We used multisite intracortical recordings from patients who under-went intracranial monitoring for refractory epilepsy, the majority of whom had a mesial temporal lobe seizure onset zone. Our objective was to evaluate the ex-istence of proepileptogenic windows before interictal epileptic discharges. We tested whether the amplitude and phase synchronization of slow oscillations (.5– 4Hz and 4– 7Hz) increase before epileptic discharges and whether the latter are phase- locked to slow oscillations. Then, we tested whether the phase- locking of neuronal activity (assessed by high- gamma activity, 60– 160Hz) to slow oscil-lations increases before epileptic discharges to provide a potential mechanism linking slow oscillations to interictal activities.Results: Changes in widespread slow oscillations anticipate upcoming epileptic discharges. The network extends beyond the irritative zone, but the increase in amplitude and phase synchronization is rather specific to the irritative zone. In contrast, epileptic discharges are phase- locked to widespread slow oscillations and the degree of phase- locking tends to be higher outside the irritative zone. Then, within the irritative zone only, we observe an increased coupling between slow oscillations and neuronal discharges before epileptic discharges.Significance: Our results show that epileptic discharges occur during vulnerable time windows set up by a specific phase of slow oscillations. The specificity of these permissive windows is further reinforced by the increased coupling of neu-ronal activity to slow oscillations. These findings contribute to our understanding of epilepsy as a distributed oscillopathy and open avenues for future neuromodu-lation strategies aiming at disrupting proepileptic mechanisms.
Databáze: OpenAIRE
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