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Lifetime distribution of mature barrel cortex in brain

Range	transient (~1 day) 17%: semi-stable (2-3 days) 23%: stable (8 days) 60% %
Organism	Mouse Mus musculus
Reference	Meyer, M.P., Niell, C.M, and Smith, S.J (2003) Brain Imaging: How stable are synaptic connections? Curr. Biol., 13(5):R180-2. p.R181 left column top paragraphPubMed ID12620207
Method	p.R180 right column bottom paragraph:"To examine the degree of spine plasticity in young adult mice beyond the critical period for somatosensory map development ref 4. And ref 12., Trachtenberg et al. [ref 2] developed a preparation for high-resolution imaging of barrel cortex in vivo. A small intracranial window centered over the barrel cortex of transgenic mice expressing the fluorescent protein EGFP in a subpopulation of layer 5 pyramidal neurons allowed visualization by two-photon microscopy of spines on layer 1 and 2 dendritic arbors (Figure 1)."
Comments	p.R181 left column top paragraph:"The same dendritic regions could be identified from day to day, allowing long-term imaging of dendritic structure. In acute experiments, few changes in spine structure were observed. But in chronic experiments, where the same region of dendrite was imaged for eight consecutive days, analysis of spine lifetime revealed a surprisingly high rate of spine turnover. On any given day, the spine population was found to be about 17% transient, 23% semi-stable and 60% stable, with lifetimes averaging a day, 2–3 days and 8 days, respectively (Figure 2A). Of the stable spines, 15% had disappeared 20–24 days later, indicating that even relatively stable spines turnover. These experiments also revealed that, despite a high rate of spine turnover, spine density was stable. Changes in dendritic structure were limited to spines, as no changes were observed at the level of dendritic branching."
Entered by	Uri M
ID	112029