Authors :
Presenting Author: Kiyohide Usami, MD, PhD – Kyoto University Hospital
Masao Matsuhashi, MD, PhD – Kyoto University Graduate School of Medicine
Akihiro Shimotake, MD, PhD – Kyoto University Graduate School of Medicine
Takuro Nakae, MD, PhD – Shiga General Hospital
Katsuya Kobayashi, MD, PhD – Kyoto University Graduate School of Medicine
Jumpei Togawa, MD, PhD – Kyoto University Graduate School of Medicine
Takefumi Hitomi, MD, PhD – Hirakata General Hospital For Developmental Disorders
Takayuki Kikuchi, MD, PhD – Kyoto University Graduate School of Medicine
Miki Nagao, MD, PhD – Kyoto University Graduate School of Medicine
Takeharu Kunieda, MD, PhD – Ehime University Graduate School of Medicine
Yoshiki Arakawa, MD, PhD – Kyoto University Graduate School of Medicine
Akio Ikeda, MD, PhD – Kyoto University Graduate School of Medicine
Riki Matsumoto, MD, PhD – Kyoto University Graduate School of Medicine.
Rationale:
Certain cortical areas in the brain are activated by various tasks. These areas are considered significant because they are associated with higher brain functions, which should be preserved during epilepsy surgery. Previous studies suggest multisensory convergence occurs in the temporo-parietal junction (Matsuhashi M., et al. 2004. Clin Neurophysiol). However, it remains unclear how they function during resting-state, and how they dynamically change across sleep stages. In this study, we examined how information flow occurs in the vicinity of the site activated by multiple tasks during wakefulness, non-REM sleep and REM sleep.
Methods:
Eight patients (5 males, 3 females) were recruited, in whom subdural electrodes were clinically implanted for presurgical investigation before epilepsy surgery from 2011 to 2023, sensory/auditory evoked potential, and naming evoked-response potential tasks were all performed, and resting-state EEG data were recorded across sleep stages (IRB#C533). Electrodes that showed activation within 5-750 ms of the stimulus onset for each task were examined. High-gamma activity (70-150 Hz) was used as a proxy for neuronal activation. Then, transfer entropy (TE) between within 1.5 cm of the activated electrodes was calculated as a function of the number of activated tasks (none and single vs. multiple). Results:
Of the 710 recording electrodes across the eight patients, 328 electrodes were activated by one task, and 99 were activated by multiple tasks (defined as information crossroads). The most of the 99 electrodes were not located in the temporo-parietal junction. Analysis of TE revealed that both inbound and outbound connectivity were significantly larger in the information crossroads during wakefulness (p = 0.006, p = 0.002). During non-REM sleep, the TE decreased regardless of the number of activated tasks, although TE was still higher in the information crossroads (inbound/outbound: p < 0.001, p < 0.001). During REM sleep, the difference of TE as a function of the number of activated tasks disappeared (inbound/outbound: p = 0.22, p = 0.24), while TE is larger compared to wakefulness (inbound/outbound, non-information crossroads/information crossroads: p < 0.05 for all, multiple comparison corrected).