Satsuki Watanabe1, François Dubeau2, Natalja Zazubovits2, Jean Gotman2. 1. Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; National Center Hospital of Neurology and Psychiatry, Tokyo, Japan. Electronic address: satsuki.watanabe@ncnp.go.jp. 2. Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
Abstract
OBJECTIVE: It has been reported that interictal epileptic discharges (IEDs) recorded in temporal regions on scalp EEG are unlikely to originate from mesial temporal structures. However, EEG-fMRI sometimes show mesial temporal activation. We hypothesized that BOLD activation in the temporal neocortex is weaker than in the mesial structures, reflecting the fact that propagated activity has less metabolic demand than the original discharge. METHODS: Twelve patients with epilepsy who have BOLD response in mesial temporal structures were selected from our EEG-fMRI database. We searched the temporal lobe ipsilateral to IEDs and checked whether there is positive BOLD response in the neocortex. RESULTS: All IED types showed a BOLD response in the temporal neocortex ipsilateral to the mesial temporal BOLD response. T-values were higher in mesial temporal structures than in neocortex in 13/16 cases. CONCLUSIONS: Hemodynamic changes were observed in the mesial temporal lobe at the time of IEDs recorded from the temporal region on the scalp. The finding of smaller BOLD changes in the ipsilateral neocortex is in agreement with our hypothesis. SIGNIFICANCE: Our study indicates that scalp-recorded temporal lobe spikes are likely to result from mesial temporal spikes propagating neuronally to the neocortex.
OBJECTIVE: It has been reported that interictal epileptic discharges (IEDs) recorded in temporal regions on scalp EEG are unlikely to originate from mesial temporal structures. However, EEG-fMRI sometimes show mesial temporal activation. We hypothesized that BOLD activation in the temporal neocortex is weaker than in the mesial structures, reflecting the fact that propagated activity has less metabolic demand than the original discharge. METHODS: Twelve patients with epilepsy who have BOLD response in mesial temporal structures were selected from our EEG-fMRI database. We searched the temporal lobe ipsilateral to IEDs and checked whether there is positive BOLD response in the neocortex. RESULTS: All IED types showed a BOLD response in the temporal neocortex ipsilateral to the mesial temporal BOLD response. T-values were higher in mesial temporal structures than in neocortex in 13/16 cases. CONCLUSIONS: Hemodynamic changes were observed in the mesial temporal lobe at the time of IEDs recorded from the temporal region on the scalp. The finding of smaller BOLD changes in the ipsilateral neocortex is in agreement with our hypothesis. SIGNIFICANCE: Our study indicates that scalp-recorded temporal lobe spikes are likely to result from mesial temporal spikes propagating neuronally to the neocortex.
Authors: Hui Ming Khoo; Nicolás von Ellenrieder; Natalja Zazubovits; Daniel He; François Dubeau; Jean Gotman Journal: Neurology Date: 2018-07-13 Impact factor: 9.910
Authors: A E Vaudano; L Mirandola; F Talami; G Giovannini; G Monti; P Riguzzi; L Volpi; R Michelucci; F Bisulli; E Pasini; P Tinuper; L Di Vito; G Gessaroli; M Malagoli; G Pavesi; F Cardinale; L Tassi; L Lemieux; S Meletti Journal: Brain Topogr Date: 2021-06-21 Impact factor: 3.020