Response of alpha wave in visual cortex with quantitative light stimulus

Electroencephalogram (EEG) is generated by collective activity of neural population. In those waves, low frequency waves, called alpha waves (8-12[Hz]), are often observed in visual cortex, and the relationship between such waves and cognitive functions have been studied by many researchers. However, the mechanism of the generation of alpha waves is not understood well. In this study, we build an experimental system that can present quantitative light stimuli, and record the response of alpha waves. As a result, we observed that the onset of the recovery of alpha waves power is delayed comparing to the end of the stimuli, and also confirmed that there is a difference between decay speed and recovery speed of the alpha waves. By comparing such results with mathematical models of alpha waves already proposed, we can understand which model conforms to real alpha waves well, and that will be helpful for understanding how alpha waves are generated, and how human visual cortex works. © 2018 The Institute of Electrical Engineers of Japan.