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Namiki K, Nakai J, Lukowiak K, Ito E. Sleep-like State in Pond Snails Leads to Enhanced Memory Formation. BIOLOGY 2024; 13:336. [PMID: 38785818 PMCID: PMC11117650 DOI: 10.3390/biology13050336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/01/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
To test the hypothesis that a sleep-like quiescent state enhances memory consolidation in the pond snail Lymnaea stagnalis, we interposed a period in which snails experienced either a quiescent, sleeping state or an active, non-sleeping state following escape behavior suppression learning (EBSL). During EBSL training, the number of escapes made by a snail from a container was significantly suppressed using an external aversive stimulus (punishment). After training, the snails were divided into two groups. One group of snails was allowed to move freely and to experience a sleep-like quiescent state for 3 h in distilled water. The other group was stimulated with a sucrose solution every 10 min to keep them active (i.e., non-sleeping). In the memory test, escape behavior was suppressed in the group that experienced the quiescent state, whereas the suppression was not observed in snails that were kept active. Additionally, the latency of the first escape in the memory test was shorter in the snails kept active than in those that experienced the quiescent state. Together, these data are consistent with the hypothesis that a sleep-like quiescent state enhances EBSL memory consolidation in L. stagnalis.
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Affiliation(s)
- Kengo Namiki
- Department of Biology, Waseda University, Tokyo 162-8480, Japan; (K.N.); (J.N.)
| | - Junko Nakai
- Department of Biology, Waseda University, Tokyo 162-8480, Japan; (K.N.); (J.N.)
| | - Ken Lukowiak
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada;
| | - Etsuro Ito
- Department of Biology, Waseda University, Tokyo 162-8480, Japan; (K.N.); (J.N.)
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Zhang S, Guo Z, Xu Y, Mi J, Liu J, Li Z, Xie X, Xu G. Transcranial magneto-acoustic stimulation improves spatial memory and modulates hippocampal neural oscillations in a mouse model of Alzheimer's disease. Front Neurosci 2024; 18:1313639. [PMID: 38384480 PMCID: PMC10879395 DOI: 10.3389/fnins.2024.1313639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/22/2024] [Indexed: 02/23/2024] Open
Abstract
Introduction In our study, we applied transcranial magneto-acoustic stimulation (TMAS), a technique based on focused ultrasound stimulation within a static magnetic field, in the APP/PS1 mouse model of Alzheimer's disease (AD) to explore the feasibility of TMAS on improving AD related spatial memory deficits and abnormal neural oscillations. Methods The mice treated with TMAS once daily for 21 days. We recorded local field potential signals in the hippocampal CA1 region of the mice after TMAS treatment with in-vivo electrophysiology and evaluated the neural rehabilitative effect of TMAS with sharp-wave ripple (SWR), gamma oscillations during SWRs, and phase-amplitude coupling (PAC). The spatial memory function of the mice was examined by the Morris water maze (MWM) task. Results We found that TMAS improved the performance of MWM related spatial cognitive functions compared with AD group. Furthermore, our results implied that TMAS alleviated abnormalities in hippocampal SWRs, increased slow gamma power during SWRs, and promoted theta-slow gamma phase-amplitude coupling. These findings suggest that TMAS could have a positive influence on spatial memory through the modulation of neural oscillations. Discussion This work emphasizes the potential of TMAS to serve as a non-invasive method for Alzheimer's disease rehabilitation and promote the application of TMAS for the treatment of more neurological and brain aging diseases in the future.
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Affiliation(s)
- Shuai Zhang
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, China
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
| | - Zhongsheng Guo
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, China
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
| | - Yihao Xu
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
| | - Jinrui Mi
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
| | - Jun Liu
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
| | - Zichun Li
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
| | - Xiaofeng Xie
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
| | - Guizhi Xu
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, China
- Hebei key Laboratory of Bioelectromagnetism and Neural Engineering, Hebei University of Technology, Tianjin, China
- Tianjin Key Laboratory of Bioelectromagnetic Technology and Intelligent Health, Tianjin, China
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Okada R, Ikegaya Y, Matsumoto N. Short-Term Preexposure to Novel Enriched Environment Augments Hippocampal Ripples in Urethane-Anesthetized Mice. Biol Pharm Bull 2024; 47:1021-1027. [PMID: 38797694 DOI: 10.1248/bpb.b24-00118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Learning and memory are affected by novel enriched environment, a condition where animals play and interact with a variety of toys and conspecifics. Exposure of animals to the novel enriched environments improves memory by altering neural plasticity during natural sleep, a process called memory consolidation. The hippocampus, a pivotal brain region for learning and memory, generates high-frequency oscillations called ripples during sleep, which is required for memory consolidation. Naturally occurring sleep shares characteristics in common with general anesthesia in terms of extracellular oscillations, guaranteeing anesthetized animals suitable to examine neural activity in a sleep-like state. However, it is poorly understood whether the preexposure of animals to the novel enriched environment modulates neural activity in the hippocampus under subsequent anesthesia. To ask this question, we allowed mice to freely explore the novel enriched environment or their standard environment, anesthetized them, and recorded local field potentials in the hippocampal CA1 area. We then compared the characteristics of hippocampal ripples between the two groups and found that the amplitude of ripples and the number of successive ripples were larger in the novel enriched environment group than in the standard environment group, suggesting that the afferent synaptic input from the CA3 area to the CA1 area was higher when the animals underwent the novel enriched environment. These results underscore the importance of prior experience that surpasses subsequent physical states from the neurophysiological point of view.
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Affiliation(s)
- Rio Okada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
- Institute for AI and Beyond, The University of Tokyo
- Center for Information and Neural Networks, National Institute of Information and Communications Technology
| | - Nobuyoshi Matsumoto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
- Institute for AI and Beyond, The University of Tokyo
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Pronier É, Morici JF, Girardeau G. The role of the hippocampus in the consolidation of emotional memories during sleep. Trends Neurosci 2023; 46:912-925. [PMID: 37714808 DOI: 10.1016/j.tins.2023.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/23/2023] [Accepted: 08/09/2023] [Indexed: 09/17/2023]
Abstract
Episodic memory relies on the hippocampus, a heterogeneous brain region with distinct functions. Spatial representations in the dorsal hippocampus (dHPC) are crucial for contextual memory, while the ventral hippocampus (vHPC) is more involved in emotional processing. Here, we review the literature in rodents highlighting the anatomical and functional properties of the hippocampus along its dorsoventral axis that underlie its role in contextual and emotional memory encoding, consolidation, and retrieval. We propose that the coordination between the dorsal and vHPC through theta oscillations during rapid eye movement (REM) sleep, and through sharp-wave ripples during non-REM (NREM) sleep, might facilitate the transfer of contextual information for integration with valence-related processing in other structures of the network. Further investigation into the physiology of the vHPC and its connections with other brain areas is needed to deepen the current understanding of emotional memory consolidation during sleep.
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Affiliation(s)
- Éléonore Pronier
- Institut du Fer à Moulin, Inserm U1270, Sorbonne Université, Paris, France
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