正文
【作者】Luisade Vivo, Michele Bellesi, William Marshall, Eric A. Bushong , Mark H. Ellisman,Giulio Tononi , Chiara Cirelli
【期刊】Science
【DOI】10.1126/science.aah5982
【摘要】Itis assumed that synaptic strengthening and weakening balance throughoutlearning to avoid runaway potentiation and memory interference. However,energetic and informational considerations suggest that potentiation shouldoccur primarily during wake, when animals learn, and depression should occurduring sleep. We measured 6920 synapses in mouse motor and sensory corticesusing three-dimensional electron microscopy. The axon-spine interface (ASI)decreased ~18% after sleep compared with wake. This decrease was proportionalto ASI size, which is indicative of scaling. Scaling was selective, sparingsynapses that were large and lacked recycling endosomes. Similar scalingoccurred for spine head volume, suggesting a distinction between weaker, moreplastic synapses (~80%) and stronger, more stable synapses. These resultssupport the hypothesis that a core function of sleep is to renormalize overallsynaptic strength increased by wake.
【论文地址】http://science.sciencemag.org/content/355/6324/507
【论文题目】Homer1adrives homeostatic scaling-down of excitatory synapses during sleep
【作者】GrahamH. Diering , Raja S. Nirujogi , Richard H. Roth , Paul F. Worley, Akhilesh Pandey , Richard L. Huganir ,
【期刊】Science
【DOI】10.1126/science.aai8355
【摘要】Sleepis an essential process that supports learning and memory by acting on synapsesthrough poorly understood molecular mechanisms. Using biochemistry, proteomics,and imaging in mice, we find that during sleep, synapses undergo widespreadalterations in composition and signaling, including weakening of synapsesthrough removal and dephosphorylation of synaptic AMPA-type glutamatereceptors. These changes are driven by the immediate early gene Homer1a andsignaling from group I metabotropic glutamate receptors mGluR1/5. Homer1aserves as a molecular integrator of arousal and sleep need via the wake- andsleep-promoting neuromodulators, noradrenaline and adenosine, respectively. Ourdata suggest that homeostatic scaling-down, a global form of synapticplasticity, is active during sleep to remodel synapses and participates in theconsolidation of contextual memory.
【论文地址】http://science.sciencemag.org/content/355/6324/511
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