Onset and propagation of spike and slow wave discharges in human absence epilepsy: A MEG study

Westmijse, I.A.M.; Ossenblok, Pauly; Gunning, Boudewijn; Luijtelaar, Gilles van

doi:10.1111/j.1528-1167.2009.02162.x

Cited by 168 publications

(148 citation statements)

References 43 publications

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“…Inactivation of the somatosensory cortex abolished SWDs in GAERS rats (Polack et al, 2009). Magnetoencephalogram and functional magnetic resonance imaging support a cortical rather than thalamic initiation of SWDs in patients with absence seizures (Bai et al, 2010;Westmijse et al, 2009).…”

Section: Introductionmentioning

confidence: 88%

The hippocampus participates in a pharmacological rat model of absence seizures

Arcaro

Chu

et al. 2016

Epilepsy Research

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SUMMARYObjective-Using the gamma-butyrolactone (GBL) model of absence seizures in Long-Evans rats, this study investigated if 2.5-6 Hz paroxysmal discharges (PDs) induced by GBL were synchronized among the thalamocortical system and the hippocampus, and whether inactivation of the hippocampus affected PDs.Methods-Local field potentials were recorded by chronically implanted depth electrodes in the neocortex (frontal, parietal, visual), ventrolateral thalamus and dorsal hippocampal CA1 area. In separate experiments, multiple unit recordings were made at the hippocampal CA1 pyramidal cell layer, or the mid-septotemporal hippocampus was inactivated by local infusion of GABA A receptor agonist muscimol.Results-As PDs developed following GBL injection, coherence of local field potentials at 2.5-6 Hz increased between the hippocampus and thalamus, and between the hippocampus and the neocortex. Hippocampal theta rhythm was disrupted when GBL induced immobility in the rats. The probability of hippocampal multiple unit firing significantly increased at 40 -80 ms prior to the negative peak of thalamic PDs. Coherence between hippocampal multiple unit activity and thalamic field potentials at 2.5-6 Hz was significantly increased after GBL injection. Muscimol infusion to inactivate the mid-septotemporal hippocampus, as compared to saline infusion, significantly decreased the peak frequency of the PDs induced by GBL, decreased 30-120 Hz hippocampal gamma power, and hastened the transition of PDs to 1-2 Hz slow waves.Significance-During GBL induced 2.5-6 Hz PDs, a hallmark of absence seizure, increased synchronization between the hippocampus and the thalamocortical network was indicated by frequency and temporal correlation analysis. These results suggest that the hippocampus was entrained by thalamocortical activity in the present model of absence seizures. Prolonged synchronization of the hippocampus may result in synaptic alterations that may explain the

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Section: Introductionmentioning

confidence: 88%

The hippocampus participates in a pharmacological rat model of absence seizures

Arcaro

Chu

et al. 2016

Epilepsy Research

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“…In Table 3.2 both the focal regions involved in the IEDs and the focal regions involved during the generalized SWDs of the same 7 patients studied are listed. The focal cortical regions involved during the spikes of the SWDs (Gupta et al, 2011;Westmijse et al, 2009) is concordant for 4 of the 6 children from whom IEDs occurred in the MEG with the location of at least 2 spike clusters. In total, the location of the sources of 10 out of the 12 identified spike clusters is concordant at the lobe level with (one of) the focal regions of the generalized SWDs, as illustrated in Fig.…”

Section: Interictal Versus Ictal Focal Regionsmentioning

confidence: 66%

“…During the 50 min recording session, data were collected in consecutive files with a duration of 5 min. For more details the reader is referred to Westmijse et al (2009). If no SWDs were seen in the MEG signal of the first five recorded files, 3 min of hyperventilation were issued in order to provoke generalized SWDs, which was required for three out of the seven patients included.…”

Section: Data Acquisitionmentioning

confidence: 99%

“…Next to the presence of IEDs and their localization in local cortical regions it is additionally described whether the underlying cortical sources of the IEDs are related to the focal cortical regions involved in the ictal 3 Hz SWD itself, as described by Westmijse et al (2009) and Gupta et al (2011). The outcomes of this study contribute to the discussion whether these IEDs, which are classically seen as a biomarker of focal epilepsies, should be considered as a manifestation of a focal or a generalized type of epilepsy.…”

Section: Introductionmentioning

confidence: 95%

“…In addition, high-resolution EEG and MEG studies in children and adults with various types of absence seizures in combination with advanced signal analytical techniques have confirmed the existence of a preferential cortical origin of SWDs. Focal cortical regions with increased connectivity were detected either in the frontal cortex, orbito-frontal, medial temporal or parietal lobe (Amor et al, 2009;Holmes et al, 2004;Tenney et al, 2013;Westmijse et al, 2009). It is obvious that this challenges the dichotomy between focal and generalized epilepsy.…”

Section: Introductionmentioning

confidence: 99%

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Spatiotemporal mapping of interictal epileptiform discharges in human absence epilepsy: A MEG study

2016

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a b s t r a c tPurpose: Although absence epilepsy is considered to be a prototypic type of generalized epilepsy, it is still under debate whether generalized 3 Hz spike-and-wave discharges (SWDs) might have a cortical focal origin. Here it is investigated whether focal interictal epileptiform discharges (IEDs), which typically occur in the electro-(EEG) and magnetoencephalogram (MEG) in case of focal epilepsy, are present in the MEG of children with absence epilepsy. Next, the location of the sources of the IEDs is established, and it is investigated whether the location is concordant to the earlier established focal cortical regions involved in the generalized SWDs of these children. Methods: Whole head MEG recordings of seven children with absence epilepsy were reviewed with respect to the presence of IEDs (spikes and sharp waves). These IEDs were grouped into distinct clusters, in which each contribution to a cluster yields a comparable magnetic field distribution. Source localization was then performed onto the average signal of each cluster using an equivalent current dipole model and a realistic head model of the cortical surface. Results: IEDs were detected in 6 out of 7 patients. Source reconstruction indicated most often frontal, central or parietal origins of the IED in either the left and or right hemisphere. Spatiotemporal assessment of the IEDs indicated a stable location of the averages of these discharges, indicating a single underlying cortical source. Discussion: The outcome of this pilot study shows that MEG is well suited for the detection of IEDs and suggests that their estimated sources coincide rather well with the cortical regions involved during the spikes of the SWDs. It is discussed whether the presence of IEDs, classically seen as a marker of focal epilepsies, indicate that absence epilepsy should be considered as a focal type of epilepsy, in which changes in the network are evolving rapidly.

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Special neurophysiological techniques

Maugui're

Jung²

2015

The Treatment of Epilepsy

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Onset and propagation of spike and slow wave discharges in human absence epilepsy: A MEG study

Cited by 168 publications

References 43 publications

The hippocampus participates in a pharmacological rat model of absence seizures

The hippocampus participates in a pharmacological rat model of absence seizures

Spatiotemporal mapping of interictal epileptiform discharges in human absence epilepsy: A MEG study

Special neurophysiological techniques

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