They locate the place of origin of electrical currents in the brain of epileptic patients

The human cerebral cortex is strongly folded and functionally segmented into hundreds of areas that vary in extent between individuals due, among other factors, to life experience itself. As a consequence, the recording of electrical activity at the same point in different people may reflect different activities and functions. Now, scientists have studied the electrical currents that spread inside the brain in records of patients with epilepsy and have managed to determine their place of origin, as well as which are related to the disease and which are not.

The study was carried out by a team led by Julia Makarova, from the Cajal Institute, attached to the Higher Council for Scientific Research (CSIC) in Spain.

The results of the study can contribute to planning clinical intervention in these patients in a personalized manner.

Intracranial electrical potentials, which represent variations in the electrical activity of the nervous system, are used as functional biomarkers of neuronal networks. “These spread inside the brain from their areas of origin and mix at the recording sites, which makes it difficult to accurately determine, for example, the areas with epileptic activity, complicating their treatment with electromagnetic devices without altering other areas. and functions,” explains Óscar Herreras, CSIC researcher at the Cajal Institute and co-author of the study.

“An important aspect of this work is the use of biomathematical techniques previously optimized in animal models, with the aim of applying scientific-technical advances in the direct study of the human brain,” comments Javier de Felipe, CSIC scientist and director of the Laboratory. Cajal of Cortical Circuits (Center for Biomedical Technology, Polytechnic University of Madrid (UPM)).

In this study, dozens of intracranial recordings have been made in epileptic patients to precisely delimit which electrical currents are epileptic and which are not, as well as identify their origin. “We have used advanced algorithms that have allowed us to determine the 3D contour of normal areas and epileptic areas and follow their activity for days. And it has been shown that any recording is a mixture of activity from between 3 and 5 different neuronal populations. Once separated, we have discovered that up to 20% of the electrodes where an epileptic attack was recorded actually captured the activity of distant populations (false positives),” says Óscar Herreras.

In the new study, it has been possible to determine the place of origin of electrical currents in the brain of epileptic patients. (Illustration: Amazings/NCYT)

By marking epileptic foci more precisely and avoiding false positives, these findings will help plan clinical intervention to break epileptic networks in a personalized way for each patient and reduce possible sequelae.

The study is titled “Intracranial voltage profiles from untangled human deep sources reveal multisource composition and source allocation bias.” And it has been published in the academic journal The Journal of Neuroscience. (Source: CSIC)