Ida A Nissen1, Nicole E C van Klink2, Maeike Zijlmans3, Cornelis J Stam4, Arjan Hillebrand5. 1. Department of Clinical Neurophysiology and MEG Center, Neuroscience Campus Amsterdam, VU University Medical Center, Postbus 7057, 1007 MB Amsterdam, The Netherlands. Electronic address: i.nissen@vumc.nl. 2. Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Postbus 85500, 3508 GA Utrecht, The Netherlands. Electronic address: N.vanKlink-2@umcutrecht.nl. 3. Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Postbus 85500, 3508 GA Utrecht, The Netherlands; SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, Postbus 540, 2130 AM Hoofddorp, The Netherlands. Electronic address: mzijlmans@hotmail.com. 4. Department of Clinical Neurophysiology and MEG Center, Neuroscience Campus Amsterdam, VU University Medical Center, Postbus 7057, 1007 MB Amsterdam, The Netherlands. Electronic address: cj.stam@vumc.nl. 5. Department of Clinical Neurophysiology and MEG Center, Neuroscience Campus Amsterdam, VU University Medical Center, Postbus 7057, 1007 MB Amsterdam, The Netherlands. Electronic address: a.hillebrand@vumc.nl.
Abstract
OBJECTIVE: Previous studies have associated network hubs and epileptiform activity, such as spikes and high frequency oscillations (HFOs), with the epileptogenic zone. The epileptogenic zone is approximated by the area that generates interictal epileptiform activity: the irritative zone. Our aim was to determine the relation between network hubs and the irritative zone. METHODS: Interictal resting-state MEG recordings of 12 patients with refractory epilepsy were analysed. Beamformer-based virtual electrodes were calculated at 70 locations around the epileptic spikes (irritative zone) and in the contralateral hemisphere. Spikes and HFOs were marked in all virtual electrodes. A minimum spanning tree network was generated based on functional connectivity (phase lag index; PLI) between all virtual electrodes to calculate the betweenness centrality, an indicator of hub status of network nodes. RESULTS: Betweenness centrality was low, and PLI was high, in virtual electrodes close to the centre of the irritative zone, and in virtual electrodes with many spikes and HFOs. CONCLUSION: Node centrality increases with distance from brain areas with spikes and HFOs, consistent with the idea that the irritative zone is a functionally isolated part of the epileptic network during the interictal state. SIGNIFICANCE: A new hypothesis about a pathological hub located remotely from the irritative zone and seizure onset zone opens new ways for surgery when epileptogenic areas and eloquent cortex coincide.
OBJECTIVE: Previous studies have associated network hubs and epileptiform activity, such as spikes and high frequency oscillations (HFOs), with the epileptogenic zone. The epileptogenic zone is approximated by the area that generates interictal epileptiform activity: the irritative zone. Our aim was to determine the relation between network hubs and the irritative zone. METHODS: Interictal resting-state MEG recordings of 12 patients with refractory epilepsy were analysed. Beamformer-based virtual electrodes were calculated at 70 locations around the epileptic spikes (irritative zone) and in the contralateral hemisphere. Spikes and HFOs were marked in all virtual electrodes. A minimum spanning tree network was generated based on functional connectivity (phase lag index; PLI) between all virtual electrodes to calculate the betweenness centrality, an indicator of hub status of network nodes. RESULTS: Betweenness centrality was low, and PLI was high, in virtual electrodes close to the centre of the irritative zone, and in virtual electrodes with many spikes and HFOs. CONCLUSION: Node centrality increases with distance from brain areas with spikes and HFOs, consistent with the idea that the irritative zone is a functionally isolated part of the epileptic network during the interictal state. SIGNIFICANCE: A new hypothesis about a pathological hub located remotely from the irritative zone and seizure onset zone opens new ways for surgery when epileptogenic areas and eloquent cortex coincide.
Authors: W J E M Zweiphenning; M A van 't Klooster; E van Diessen; N E C van Klink; G J M Huiskamp; T A Gebbink; F S S Leijten; P H Gosselaar; W M Otte; C J Stam; K P J Braun; G J M Zijlmans Journal: Neuroimage Clin Date: 2016-11-04 Impact factor: 4.881
Authors: Eleonora Tamilia; Joseph R Madsen; Patricia Ellen Grant; Phillip L Pearl; Christos Papadelis Journal: Front Neurol Date: 2017-01-30 Impact factor: 4.003
Authors: Ida A Nissen; Cornelis J Stam; Elisabeth C W van Straaten; Viktor Wottschel; Jaap C Reijneveld; Johannes C Baayen; Philip C de Witt Hamer; Sander Idema; Demetrios N Velis; Arjan Hillebrand Journal: Front Neurol Date: 2018-08-07 Impact factor: 4.003
Authors: Erika L Juárez-Martinez; Ida A Nissen; Sander Idema; Demetrios N Velis; Arjan Hillebrand; Cornelis J Stam; Elisabeth C W van Straaten Journal: Neuroimage Clin Date: 2018-06-02 Impact factor: 4.881
Authors: S Kathleen Bandt; Pierre Besson; Ben Ridley; Francesca Pizzo; Romain Carron; Jean Regis; Fabrice Bartolomei; Jean Philippe Ranjeva; Maxime Guye Journal: Neuroimage Clin Date: 2019-10-23 Impact factor: 4.881
Authors: Ida A Nissen; Ana P Millán; Cornelis J Stam; Elisabeth C W van Straaten; Linda Douw; Petra J W Pouwels; Sander Idema; Johannes C Baayen; Demetrios Velis; Piet Van Mieghem; Arjan Hillebrand Journal: Sci Rep Date: 2021-09-24 Impact factor: 4.379