Cortical and subcortical intraoperative-monitoring of the visual pathway under general anesthesia in epilepsy surgery.

Objective: The purpose of this study was to evaluate the applicability of visual evoked potentials (VEP) for intraoperative visual pathway monitoring in epilepsy surgery of the posterior hemispheric quadrant (PHQ) and to correlate it with post-operative visual field status.

Methods: VEP monitoring was performed in 16 patients (12 females, 7 children). Flash-induced VEP were recorded with strip electrodes from the banks of the calcarine cortex.

Thalamic feedback shapes brain responses evoked by cortical stimulation in mice and humans.

Cortical stimulation with single pulses is a common technique in clinical practice and research. However, we still do not understand the extent to which it engages subcortical circuits which contribute to the associated evoked potentials (EPs). Here we find that cortical stimulation generates remarkably similar EPs in humans and mice, with a late component similarly modulated by the subject's behavioral state.

Neocortical and medial temporal seizures have distinct impacts on brain responsiveness.

Focal epileptic seizures are characterized by abnormal neuronal discharges that can spread to other cortical areas and interfere with brain activity, thereby altering the patient's experience and behavior. The origin of these pathological neuronal discharges encompasses various mechanisms that converge toward similar clinical manifestations. Recent studies have suggested that medial temporal lobe (MTL) and neocortical (NC) seizures are often underpinned by two characteristic onset patterns, which, respectively, affect and spare synaptic transmission in cortical slices.