Shinji Urakami, a master's degree student at the Graduate School of Health Sciences, Kio University (currently affiliated with Hoshigaoka Medical Center) and Associate Professor Michihiro Osumi of the University's Neurorehabilitation Research Center, experienced the thermal grill illusion. It was clarified that characteristic electroencephalogram activity was observed in the human brain.
When you touch something warm and something cold at the same time, you may experience "pain," and this experience is called the "thermal grill illusion."For example, placing a hand on a grill with alternating hot and cold bars evokes a painful burning sensation when it should not be hot.Although this phenomenon is thought to be caused by a central nervous system mechanism, the mechanism has not yet been fully elucidated.
In this study, we asked 21 healthy subjects to participate in the experiment, and by measuring and analyzing the brain wave activity during the thermal grill illusion, we attempted to extract the brain wave components characteristic of the thermal grill illusion.As a result, when you place your hand on a grill with alternating hot and cold bars and experience the thermal grill illusion, unlike when you place your hand on a grill with only warm bars, We discovered characteristic changes in EEG rhythms around the insular cortex, which is representative of the pain-related brain area/Pain Matrix.In other words, we can assume that the brain region that causes the illusion of thermal grilling is located in the insular cortex.
The insular cortex is a brain region involved in warm/cold sensory input as well as the emotional experience of 'pain', as well as causing central pain.This study not only clarified one end of the central nervous system mechanism in the thermal grill illusion, but is also considered to be a useful result for elucidating the mechanism of central pain.
Paper information:[NeuroReport] Cortical oscillatory changes during thermal grill illusion
