Learn More
Discrete high-frequency oscillations (HFOs) in the range of 100-500 Hz have previously been recorded in human epileptic brains using depth microelectrodes. We describe for the first time similar oscillations in a cohort of unselected focal epileptic patients implanted with EEG macroelectrodes. Spectral analysis and visual inspection techniques were used to(More)
PURPOSE High-frequency oscillations (HFOs) known as ripples (80-250 Hz) and fast ripples (250-500 Hz) can be recorded from macroelectrodes inserted in patients with intractable focal epilepsy. They are most likely linked to epileptogenesis and have been found in the seizure onset zone (SOZ) of human ictal and interictal recordings. HFOs occur frequently at(More)
EEG-fMRI is a non-invasive technique that allows the investigation of epileptogenic networks in patients with epilepsy. Lately, BOLD changes occurring before the spike were found in patients with generalized epilepsy. The study of metabolic changes preceding spikes might improve our knowledge of spike generation. We tested this hypothesis in patients with(More)
Current resting-state network analysis often looks for coherent spontaneous BOLD signal fluctuations at frequencies below 0.1 Hz in a multiple-minutes scan. However hemodynamic signal variation can occur at a faster rate, causing changes in functional connectivity at a smaller time scale. In this study we proposed to use MREG technique to increase the(More)
Epileptic seizures are due to abnormal synchronized neuronal discharges. Techniques measuring electrical changes are commonly used to analyze seizures. Neuronal activity can be also defined by concomitant hemodynamic and metabolic changes. Simultaneous electroencephalogram (EEG)-functional MRI (fMRI) measures noninvasively with a high-spatial resolution(More)
PURPOSE Absences are characterized by an abrupt onset and end of generalized 3-4 Hz spike and wave discharges (GSWs), accompanied by unresponsiveness. Although previous electroencephalography-functional magnetic resonance imaging (EEG-fMRI) studies showed that thalamus, default mode areas, and caudate nuclei are involved in absence seizures, the(More)
INTRODUCTION Seizures occur rarely during EEG-fMRI acquisitions of epilepsy patients, but can potentially offer a better estimation of the epileptogenic zone than interictal activity. Independent component analysis (ICA) is a data-driven method that imposes minimal constraints on the hemodynamic response function (HRF). In particular, the investigation of(More)
PURPOSE High-frequency activity has been recorded with intracerebral microelectrodes in epileptic patients and related to seizure genesis. Our goal was to analyze high-frequency activity recorded with electroencephalograph (EEG) macroelectrodes during the slow wave immediately following interictal spikes, given the potential importance of this presumed(More)
Malformations of cortical development (MCDs) are commonly complicated by intractable focal epilepsy. Epileptogenesis in these disorders is not well understood and may depend on the type of MCD. The cellular mechanisms involved in interictal and ictal events are notably different, and could be influenced independently by the type of pathology. We evaluated(More)
OBJECTIVE Idiopathic generalized epilepsies (IGE) are characterized by specific EEG changes including 3- to 5-Hz generalized spike-and-wave discharges. The thalamus and its cortical interactions are considered essential in the production and propagation of spike-and-wave discharges. In animal studies, corticoreticular and limbic system property changes have(More)