Influence of Brain Cooling on Frequency Characteristics of the Epileptic Focus and its Surrounding Area

In this study, we examined the suppression effect of brain cooling on the epileptic focus and surrounding area. An epileptic seizure was induced in rats to obtain electrocorticography (ECoG) data when brain cooling was performed on the epileptic focus and its surroundings. Then, the frequency response characteristics were calculated by applying fast Fourier transform (FFT) and band pass filter to the obtained multichannel brain wave data. At this time, the frequency band calculated by the band pass filter was α waves (8.0–13.0Hz) and β waves (13.0–30.0 Hz) which were remarkably observed in epileptic seizure in the previous study, the analysis window of FFT was 4.095 seconds, and the overlap was 75%. As a result of comparing the calculated frequency responses for each rat, it was found that at the site where epileptic seizures were observed, power was reduced by cooling and suppressing effect was observed, whereas at the same time, the power increased at the site a few millimeters adjacent to the seizure site. This result suggests that epileptic waves suppressed by brain cooling might propagate to the surrounding area by a few millimeters.