Yoshichika Yoshioka1, 2, Hiroshi Oikawa3, Yoshiyuki Kanbara4, Yutaka Matsumura4, Takashi Inoue5, Yutaka Shinohe6, Shigeharu Joh6, Tsuyoshi Matsuda7, Akira Nabatani8, Junji Seki9
1Immunology Frontier Research Center (WPI-IFReC), Osaka University, Suita, Osaka, Japan; 2Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Suita, Osaka, Japan; 3Radiology, Ninohe Hospital, Ninohe, Iwate, Japan; 4High Field MRI Research Institute, Iwate Medical University, Takizawa, Iwate, Japan; 5Neurosurgery, Kohnan Hospital, Sendai, Miyagi, Japan; 6Dental Anesthesiology, Iwate Medical University, Morioka, Iwate, Japan; 7Applied Science Laboratory, GE Healthcare Japan, Hino, Tokyo, Japan; 8Madical Imaging Strategic Planning Div., Canon, Ohtaku, Tokyo, Japan; 9National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
Physiological human brain temperatures have been measured by MRS. However, it is not clear whether the brain temperature rises or falls during brain activations. We have tried to monitor brain temperature changes during exercises and some other maneuvers. We found that the brain temperatures fall during light tasks such as hand grasp, tongue stimulation, and sedation. We also could estimate the brain energy decrease during sedation as 0.2 W (estimated as a whole brain) with brain temperature changes. The energy difference between arousal and sedation in our case was about 1 % of the energy that brain needs.