Preictal neuronal and vascular activity precedes the onset of childhood absence seizure: direct current potential shifts and their correlation with hemodynamic activity

Abstract

Significance, Aims: The neurovascular mechanisms underlying the initiation of absence seizures and their dynamics are still not well understood. The objective of this study was to better noninvasively characterize the dynamics of the neuronal and vascular network at the transition from the interictal state to the ictal state of absence seizures and back to the interictal state using a combined electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS), and diffuse correlation spectroscopy (DCS) approach. The second objective was to develop hypotheses about the neuronal and vascular mechanisms that propel the networks to the 3-Hz spikes and wave discharges (SWDs) observed during absence seizures.Approaches: We evaluated the simultaneous changes in electrical (neuronal) and optical dynamics [hemodynamic, with changes in (Hb) and cerebral blood flow] of 8 pediatric patients experiencing 25 typical childhood absence seizures during the transition from the interictal state to the absence seizure by simultaneously performing EEG, fNIRS, and DCS.Results: Starting from ∼20 s before the onset of the SWD, we observed a transient direct current potential shift that correlated with alterations in functional fNIRS and DCS measurements of the cerebral hemodynamics detecting the preictal changes.Discussion: Our noninvasive multimodal approach highlights the dynamic interactions between the neuronal and vascular compartments that take place in the neuronal network near the time of the onset of absence seizures in a very specific cerebral hemodynamic environment. These noninvasive approaches contribute to a better understanding of the electrical hemodynamic environment prior to seizure onset. Whether this may ultimately be relevant for diagnostic and therapeutic approaches requires further evaluation.

Concurrent functional ultrasound imaging with graphene-based DC-coupled electrophysiology as a platform to study slow brain signals and cerebral blood flow under control and pathophysiological brain states

“…Consistent with other recent findings, we observed a decrease in blood flow to the brain in the seconds before transition to seizure, and an increase during the seizure. 24,25 Seizures that occurred with CSDs showed more complex NVC responses, with increases of rCBV in cortical regions and a delayed reduction of rCBV in subcortical regions including the hippocampus.…”

Multi-scale modelling of the epileptic brain: advantages of computational therapy exploration

“…Furthermore, The modelling community, in general, has ignored the impact of infra-slow brain signals and their causal links with seizure dynamics, with a few exceptions [22,74]. For absence epilepsy, spike and wave discharges have been seen to occur on the rise of an infralow oscillation [75,76].…”