To elucidate the function and organization of the complicated central nervous system, we have been developing novel methods using viral vectors. By using viral vectors and in vitro electrophysiological techniques, we are examining the complex wiring of the hippocampal/parahippocampal region in rodents. Our final goal is to reveal the function of the newly identified circuits, and understand the mechanism of memory formation.
|Activities in Academic Societies||
Japan Neuroscience Society
Introductory Science Experiments (General Education), Laboratory of Developmental Biology (undergraduate), etc.
The entorhinal cortex, in particular neurons in layer V, are the main recipient of hippocampal projections, and originate the main output to the neocortex. This hippocampal output circuit via layer V is considered to play an important role in transferring transiently stored information in the hippocampus to downstream neocortical networks for long-term memory formation. Recently, this circuit has been shown to comprise a hippocampal output recipient layer Vb and a cortical projecting layer Va. To delineate the organization of this hippocampal output circuit, we examined the connection from layer Vb-to-Va with the use of in vitro electrophysiology in transgenic mice specific for layer Vb. To our surprise, we found that the local circuits of layer Vb neurons differ between the functionally distinct medial (MEC) and lateral (LEC) subdivisions: connections from layer Vb-to-Va neurons are stronger in dorsal LEC compared with dorsal MEC. Although further in vivo experiments are needed, our findings imply a potential difference in how LEC and MEC mediate long-term memory formation (Ohara et al., eLife, 2021). This study was conducted in Kavli Institute for Systems Neurosciene, NTNU, together with Prof. Menno Witter, Prof. Clifford Kentros, and their colleagues.