News
21/12/2016

CEXS-UPF: Why does exposure to rhythmic stimulation at certain frequencies facilitate the occurrence of epileptic seizures?

CEXS-UPF: Why does exposure to rhythmic stimulation at certain frequencies facilitate the occurrence of epileptic seizures?


News from CEXS-UPF


In 1997, flickering patterns in an episode of the series Pokémon triggered epileptic seizures in nearly 700 Japanese children. These spontaneous outbreaks in apparently healthy children were linked to so-called "photosensitive epilepsy", a type of epilepsy in which seizures are the result of certain visual stimuli. Now researchers at UPF, Polytechnic University of Catalonia (UPC) and the University of Exeter (UoE, UK) propose an explanation for the occurrence of epileptic seizures as a result of the exposure to certain stimuli. The study has been published in the journal NeuroImage.

Considering the brain as a dynamic system allows engaging tools from engineering and physics in order to find out what factors lead to the occurrence of these highly synchronized epileptic discharges. The research by UPF, UPC and UoE has used a computational model of a cortical column - a putative basic functional unit of the cerebral cortex - to show that neuronal tissue displays epileptic-like activity when exposed to enhanced stimulation of certain frequencies. This increase may be due to the brain's own activity or a consequence of external stimulation, such as the flickering in the Pokémon cartoon.

According to the research results, this behaviour stems from dynamic properties of the neuronal tissue, such as an ability to undergo resonance. Visual stimulation with frequencies close to alpha rhythm (which was the case of the flickering in Pokémon) may interfere with the natural alpha activity prevailing in the visual cortex leading to an increase of amplitude of the discharges and consequently to epileptic seizures. 

More information:
CEXS-UPF website

Reference work:
Maciej Jedynak, Antonio J. Pons, Jordi Garcia-Ojalvo, Marc Goodfellow Temporally correlated fluctuations drive epileptiform dynamics. NeuroImage, Open Access funded by Engineering and Physical Sciences Research Council. http://dx.doi.org/10.1016/j.neuroimage.2016.11.034