Hippocampal Organization of Spatial Map

• Project/Area Number: 18K03168
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 10040:Experimental psychology-related
• Research Institution: University of Tsukuba
• Principal Investigator: Pavlides C 筑波大学, 人間系, 研究員 (50712808)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: hippocampus / med. entorhinal cortex / lat. entorhinal cortex / immediate early genes / sleep / cluster organization / memory / optogenetics / MEC/LEC / Zif268 / functional organization / spatial navigation / place cells / Hippocampus / fear memory / spatial memory / immediate-early genes / entorhinal cortex

Outline of Final Research Achievements

We undertook a set of experiments to determine: 1) functional neuronal organization in the hippocampus for the encoding of different types of memories; 2) effects of sleep on functional organization; and 3) possible differential role of medial and lateral entorhinal cortex (MEC, LEC) in spatial and object memory. We found that indeed, there was a formation of clusters in fear conditioned animals, in comparison to non-shocked controls. Further, sleep following conditioning enhanced cluster formation. In a second study, we found a similar cluster-type organization to encode sequential memory, suggesting that cluster-type is a fundamental principle for memory formation in the hippocampus. In a third study, we found that optogenetic suppression of neuronal activity in the MEC disrupted spatial memory while suppression of activity in LEC disrupted object memory. Effects on hippocampal neuronal activity of such suppression on hippocampal clustering are now being tested.

Academic Significance and Societal Importance of the Research Achievements

It is known that the hippocampus is involved in memory. Very little is known of how memory is organized in this structure. We had previously shown a cluster-type organization for the encoding of spatial memory. The current studies provide evidence that all types of memories are encoded in clusters.

Research Products

• [Journal Article] Hippocampal cellular functional organization for fear memory: effects of sleep (2022)
  • Author(s): Cho, J. and Pavlides, C.
  • Journal Title: Hippocampus Volume: 32 Issue: 11-12 Pages: 839-856
  • DOI: 10.1002/hipo.23477
  • Peer Reviewed
• [Journal Article] Hippocampal functional organization: A microstructure of the place cell network encoding space. (2019)
  • Author(s): Pavlides, C., Donishi, T., Ribeiro, S., Mello, C.V., Blanco, W., and Ogawa, S.
  • Journal Title: Neurobiology of Learning and Memory Volume: 161 Pages: 122-134
  • DOI: 10.1016/j.nlm.2019.03.010
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Fear memory consolidation in sleep requires protein kinase A. (2018)
  • Author(s): Cho, J., Sypniewski, K.A., Arai, S., Yamada, K., Ogawa, S., and Pavlides, C.
  • Journal Title: Learning and Memory Volume: 25 Issue: 5 Pages: 241-246
  • DOI: 10.1101/lm.046458.117
  • Peer Reviewed / Open Access
• [Presentation] The role of the medial and lateral entorhinal cortex in place and object fear memory. (2022)
  • Author(s): Arai, S. Sypniewski, K.A. and Pavlides, C
  • Organizer: The 45th Annual Meeting of the Japan Neuroscience Society
  • Int'l Joint Research
• [Presentation] The role of the medial and lateral entorhinal cortex in place and object fear memory. (2021)
  • Author(s): Arai, S., Sypniewski, K.A. and Pavlides, C.
  • Organizer: The 44th annual meeting of the Japan Neuroscience Society
• [Presentation] The role of the medial and lateral entorhinal cortex in memory. (2020)
  • Author(s): Arai, S., Sypniewski, K.A. and Pavlides, C.
  • Organizer: The 43th Annual meeting of the Japan Neuroscience Society
  • Int'l Joint Research
• [Presentation] The Role of the Medial and Lateral Entorhinal Cortex in Episodic Memory (2020)
  • Author(s): Arai, S., Sypniewski, K.A. and Pavlides, C.
  • Organizer: Tsukuba Global Science Week 2020 Digital Poster Session
  • Int'l Joint Research
• [Presentation] The role of the medial and lateral entorhinal cortex in memory. (2020)
  • Author(s): Arai, S. Sypniewski, KA and Pavlides, C.
  • Organizer: The 43rd Annual meeting of the Japan Neuroscience Society
  • Int'l Joint Research
• [Presentation] Hippocampal functional neuronal organization for spatial and episodic memory. (2020)
  • Author(s): Pavlides, C. Cho, J. Arai, S. and Sypniewski, KA.
  • Organizer: 12th FENS Forum of Neuroscience
  • Int'l Joint Research
• [Presentation] Hippocampal Functional Organization in Contextual Fear Memory Task. (2019)
  • Author(s): Arai, S. and Pavlides, C.
  • Organizer: The 42th Annual meeting of the Japan Neuroscience Society
  • Int'l Joint Research
• [Presentation] Hippocampal Functional Organization in Fear Memory. (2019)
  • Author(s): Arai, S. and Pavlides, C.
  • Organizer: The 30th meeting of the Japanese Society for Behavioral Neuroendocrinology
• [Presentation] Memory Consolidation in Sleep (2019)
  • Author(s): Pavlides, C.
  • Organizer: The Third Sino-Japan session: Symposium on the Frontier of Behavioral Neuroendocrinology.
  • Int'l Joint Research / Invited
• [Presentation] Hippocampal Functional Organization in Contextual Fear Memory Task. (2019)
  • Author(s): Arai, S. and Pavlides, C.
  • Organizer: The 42nd Annual meeting of the Japan Neuroscience Society
• [Presentation] Functional 3D-Reconstruction of the Hippocampus in a Spatial Memory Task. (2018)
  • Author(s): Arai, S. and Pavlides, C.
  • Organizer: The 41st Annual meeting of the Japan Neuroscience Society