Shigeyoshi Fujisawa, Ph.D.

Research Overview

Our main research goal is to elucidate the mechanisms of cognitive functions such as episodic memory and spatiotemporal recognition at the neural circuit level. To achieve this goal, we conduct studies using large-scale extracellular recordings from the hippocampus and cortex of behaving animals, such as rats, using silicon probes to simultaneously observe the activity of numerous neurons. Furthermore, by analyzing these data and constructing mathematical models, we aim to uncover how neurons contribute to cognitive functions and perform local circuit computations.

Keywords

• Neurophysiology

Selected Publications

1. Ouchi A & Fujisawa S
   “Predictive grid coding in the medial entorhinal cortex”
   Science, 385:776-784. (2024)
2. Glykos V & Fujisawa S
   “Memory-specific encoding activities of the ventral tegmental area dopamine and GABA neurons”
   Elife, 12:RP89743. (2024)
3. Kawahara D & Fujisawa S
   “Advantages of persistent cohomology in estimating animal location from grid cell population aactivity” Neural Computation, 36:385-411. (2024)
4. Shimbo A, Izawa EI, & Fujisawa S
   “Scalable representation of time in the hippocampus”
   Science Advances, 7:eabd7013. (2021)
5. Norimoto H, Makino K, Gao M, Shikano Y, Okamoto K, Ishikawa T, Sasaki T, Hioki H, Fujisawa S, & Ikegaya Y.:
   "Hippocampal ripples down-regulate synapses."
   Science, 359:524-1527. (2018)
   10.1126/science.aao0702
6. Danjo T, Toyoizumi T, & Fujisawa S.:
   "Spatial representations of self and other in the hippocampus."
   Science, 359:213-218. (2018)
   10.1126/science.aao3898
7. Terada S, Sakurai Y, Nakahara H, & Fujisawa S..:
   "Temporal and rate coding for discrete event sequences in the hippocampus."
   Neuron, 94:1248–62 (2017)
   10.1016/j.neuron.2017.05.024