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These seizures typically last for a few seconds to several minutes and include a regular electroencephalographic pattern known as spike-and-wave discharge (SWD) with a frequency of 2-5 Hz ( Szaflarski et al. The significance of the findings is useful and the strength of the evidence is incomplete but could be strengthened after additional experiments.Ībsence seizures typically appear in children between the ages of 5 and 7, and are characterized by a sudden, brief impairment of consciousness, an interruption from ongoing activities, and an unresponsiveness to environmental stimuli ( Loiseau, Duché, and Pédespan 1995). The results suggest that the brain responsiveness is reduced during the seizures. This study used fMRI in an animal that simulates a type of epilepsy to ask if the responsiveness of the brain was altered during a seizure. These results suggest that typical information flow in functional pathways responsible for processing sensory stimulation is hindered and suppressed during absence seizures, potentially contributing to decreased responsiveness. The simulation results agreed well with fMRI findings, showing restricted propagation of spontaneous activity due to stimulation. In several cortical regions, hemodynamic responses were negatively polarized during seizures, despite the application of a stimulus. Results showed that whole-brain responses to both sensory stimulations were suppressed and spatially hindered during a seizure. Additionally, a mean-field simulation model was used to mechanistically explain the changes of neural responsiveness to visual stimulation between interictal and ictal states. Sensory stimulations were applied in 28 fMRI sessions during interictal and ictal periods, as assessed by concurrent EEG recordings, and whole brain responsiveness and hemodynamic responses were compared between these two states. Animals were imaged continuously using a quiet zero-echo-time functional magnetic resonance imaging (fMRI) sequence while in a non-curarized awake state, allowing for naturally occurring seizures to be produced inside the 9.4T magnet.

This study aimed to investigate whole-brain responsiveness to visual and somatosensory whisker stimulation in GAERS, a well-established rat model for absence epilepsy. The mechanism underlying the reduced responsiveness to external stimulus remains unknown.

In patients suffering absence epilepsy, recurring seizures can significantly decrease their quality of life and lead to yet untreatable comorbidities. Absence seizures are characterized by regular and generalized spike-and-wave electrical patterns in the brain, resulting in unresponsiveness to environmental stimuli.