Hippocampal ripples down-regulate synapses

Hiroaki Norimoto, Kenichi Makino, Mengxuan Gao, Yu Shikano, Kazuki Okamoto, Tomoe Ishikawa, Takuya Sasaki, Hiroyuki Hioki, Shigeyoshi Fujisawa, Yuji Ikegaya

Research output: Contribution to journalArticle

43 Citations (Scopus)


The specific effects of sleep on synaptic plasticity remain unclear.We report that mouse hippocampal sharp-wave ripple oscillations serve as intrinsic events that trigger long-lasting synaptic depression. Silencing of sharp-wave ripples during slow-wave states prevented the spontaneous down-regulation of net synaptic weights and impaired the learning of new memories.The synaptic down-regulation was dependent on the N-methyl-D-aspartate receptor and selective for a specific input pathway.Thus, our findings are consistent with the role of slow-wave states in refining memory engrams by reducing recent memory-irrelevant neuronal activity and suggest a previously unrecognized function for sharp-wave ripples.

Original languageEnglish
Pages (from-to)1524-1527
Number of pages4
Issue number6383
Publication statusPublished - 2018 Mar 30


ASJC Scopus subject areas

  • General

Cite this

Norimoto, H., Makino, K., Gao, M., Shikano, Y., Okamoto, K., Ishikawa, T., Sasaki, T., Hioki, H., Fujisawa, S., & Ikegaya, Y. (2018). Hippocampal ripples down-regulate synapses. Science, 359(6383), 1524-1527. https://doi.org/10.1126/science.aao0702