Epilepsy Networks and Their Surgical Relevance

Hines, Kevin; Wu, Chengyuan

doi:10.3390/brainsci14010031

Cited by 2 publications

(1 citation statement)

References 69 publications

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“…This approach should extend beyond the conventional focus on isolated zones to encompass a broader understanding and targeting of the network involved in seizure generation and propagation. Such a comprehensive strategy is necessary for enhancing surgical outcomes and providing more effective treatment avenues for individuals with epilepsy [ 37 , 38 ]. In a previous study, brain connections between the epileptogenic zone and propagation zone during the interictal period appeared to be strengthened [ 39 ], and the broader were the changes, the poorer the postsurgical results tended to be.…”

Section: Temporal and Spatial Network Formationmentioning

confidence: 99%

Understanding epileptogenesis from molecules to network alteration

Park

2024

encephalitis

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Epilepsy is characterized by recurrent seizures. Following an initial insult, a latent period precedes the onset of spontaneous seizures, a process referred to as epileptogenesis. This period plays a critical role in halting the progression toward epilepsy before the onset of abnormal molecular and network alterations. In this study, the fundamental concepts of epileptogenesis as well as the associated molecular and cellular targets are reviewed.

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Section: Temporal and Spatial Network Formationmentioning

confidence: 99%

Understanding epileptogenesis from molecules to network alteration

Park

2024

encephalitis

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Collapse of Interictal Suppressive Networks Permits Seizure Spread

Makhoul,

Doss,

Johnson

et al. 2024

Preprint

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How do networks in the brain limit seizure activity? In the Interictal Suppression Hypothesis (ISH), we recently postulated that high inward connectivity to seizure onset zones (SOZs) from non-involved zones (NIZs) is a sign of broader network suppression at rest. If broad networks appear to be responsible for interictal SOZ suppression, what changes during seizure initiation, spread, and termination? For patients with drug resistant epilepsy, intracranial monitoring offers a view into the electrographic networks which organize around and in response to the SOZ. In this manuscript, we investigate network dynamics in the peri-ictal periods to assess possible mechanisms of seizure suppression and the consequences of this suppression being overwhelmed. Peri-ictal network dynamics were derived from stereo electroencephalography (SEEG) recordings from 75 patients with drug-resistant epilepsy undergoing pre-surgical evaluation at Vanderbilt University Medical Center. We computed directed connectivity from 5-second windows in the periods between, immediately before, during, and after seizures. After aligning all network connectivity matrices between seizures and patients, we calculated net connectivity changes from the SOZ, propagative zone (PZ), and NIZ. Across all seizure types, we observed two distinct phases as seizures initiated and evolved: a large rapid increase in directed communication towards the SOZ from NIZ followed by a collapse in network connectivity. During this first phase, SOZs could be distinguished from all other regions (One-Way ANOVA, p=8.32x10-19 - 2.22x10-7, lower range to upper range of p-values). In the second phase and post-ictal period, SOZ inward connectivity decreased yet remained distinct (One-Way ANOVA, p= 2.58x10-10-1.66x10-2). Furthermore, NIZs appeared to drive the increase in inward SOZ connectivity while global connectivity between NIZs concordantly decreased. Stratifying by seizure subtype, we found that consciousness-impairing seizures show loss of inward connectivity from the NIZ earlier than conscious sparing seizures (one-way ANOVA, p<0.01 after false discovery correction). Tracking network reorganization against a surrogate for seizure involvement highlighted a possible antagonism between seizure propagation to the NIZ and the NIZ's ability to maintain high connectivity to the SOZ. Finally, we found that inclusion of peri-ictal connectivity improved SOZ classification accuracy from previous models to a combined area under the curve of 93%. Overall, NIZs appear to actively respond to seizure onset and increase inhibitory signaling towards the SOZ, possibly in an attempt to thwart seizure activity. This inhibition appears to be insufficient to prevent seizure onset, and furthermore, loss of normal communication in the rest of the brain between NIZs may contribute to loss of consciousness during larger seizures. Dynamic connectivity patterns uncovered in this work may: i) allow more accurate delineation of surgical targets in focal epilepsy, ii) reveal why inward suppression of SOZs interictally may nonetheless be insufficient to prevent all seizures, and iii) provide insight into mechanisms of loss of consciousness during certain seizures.

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Epilepsy Networks and Their Surgical Relevance

Cited by 2 publications

References 69 publications

Understanding epileptogenesis from molecules to network alteration

Understanding epileptogenesis from molecules to network alteration

Collapse of Interictal Suppressive Networks Permits Seizure Spread

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