Optical imaging of epileptiform activity in human neocortex

Area of Science:

• Neuroscience
• Medical Imaging
• Epileptology

Background:

• Surgical outcomes for neocortical epilepsy lag behind those for mesial temporal sclerosis.
• Accurate mapping of neocortical epileptic tissue remains a significant challenge in surgical treatment.
• Optical spectroscopic properties of brain tissue correlate with neuronal activity.

Purpose of the Study:

• To evaluate the efficacy of imaging of intrinsic optical signals (IIOS) in precisely localizing neocortical epileptic foci.
• To investigate the use of IIOS for mapping both spontaneous and evoked epileptiform activity.
• To assess the potential of IIOS as an intraoperative tool for neocortical epilepsy surgery.

Main Methods:

• Acquisition of high-resolution IIOS maps during surgery for medically intractable neocortical epilepsy.
• Monitoring of spontaneous and stimulation-evoked epileptiform activity.
• Analysis of optical signal changes related to cerebral hemodynamics, specifically blood volume and oxygenation.

Main Results:

• IIOS successfully localized neocortical epileptic foci with high precision.
• The method effectively utilized changes in blood volume to distinguish epileptic foci, outperforming blood oxygenation changes.
• Both spontaneous and evoked epileptiform activity were accurately mapped.

Conclusions:

• Imaging of intrinsic optical signals precisely localizes neocortical epileptic foci by detecting blood volume changes.
• IIOS demonstrates significant potential to transition from a research tool to a valuable intraoperative technique for neocortical epilepsy surgery.
• This advancement may lead to improved surgical outcomes for patients with neocortical epilepsy.