演題番号 : P1-m09
藤原 清悦 / Sei-etsu Fujiwara:1 明間 立雄 / Tatsuo Akema:1 伊崎 義憲 / Yoshinori Izaki:1
1:聖マリアンナ医科大学 生理学教室 / Department of Physiology, St. Marianna University School of Medicine
Functional connectivity is an important aspect for understanding information representation in the brain´s neuronal networks. The functional connection between the posterior hippocampus (HPC) and the medial prefrontal cortex (PFC) can play a salient role in information processing because of these regions involvements in learning and memory, direct anatomical connection. Based on results of some learning experiments, their functional relation has been reported. Previously, we reported that significant peak of cross-correlogram(CC) between HPC and PFC can be detected based on multiple unit activities (MUAs) in urethane-anesthetized rats. The CCs can be classified into 2 types by the shapes: type HP (the HPC mainly fired before the PFC) and type PH (the PFC mainly fired before the HPC), and can be useful as a measure of functional connectivity between the HPC and PFC. Urethane anesthesia induces slow wave oscillation in the cortical neuronal activities mimicking cortical up/down state as seen in slow wave sleep. And synchronous firing between the HPC and PFC occurring in the up state is thought to information flow for memory function. In the present study, MUA-based CCs were analyzed in awake-quiescent rats, and which was compared with urethane-anesthetized rats. In quiescent state rats, significant peaks of CCs were also observed, however, only type HP was observed. The peak width and height of CCs were significantly narrow and low than those of urethane anesthetized rats. Furthermore, there were significant short peak lags in quiescent rats compared with urethane-anesthetized rats. These differences of the CCs between anesthetized and quiescent states suggest that the functional connectivity between HPC and PFC during quiescent states is different in information processing manor from urethane anesthesia.