94% of spines were stable >three days: 81% stable >2 weeks: 73% stable >one month %
||Mouse Mus musculus
||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 right column top paragraphPubMed ID12620207
||J. Grutzendler, K. Narayanan, W.-B. Gan Long-term dendritic spine stability in the adult cortex Nature, 420 (2002), pp. 812–816PubMed ID12490949
||p.R181 left column bottom paragraph:"Grutzendler et al. [primary source] took a similar approach to studying structural plasticity of dendritic spines, but in the visual cortex. They shaved down an area of skull in transgenic mice expressing yellow fluorescent protein (YFP) in layer 5 pyramidal neurons of the cortex. Filopodia and spines on apical dendrites in layer 1 and 2 were visualized at high resolution through the thinned area of skull using two-photon microscopy (Figure 1)."
||p.R181 right column top paragraph:"In relatively immature, one month old mice, two populations of dendritic protrusions were observed: highly dynamic filopodia, which were long, thin and lacked spine heads, 90% of which were seen to appear, disappear, extend or retract over a four hour period and spines, only 1% of which extended or retracted over the same interval (Figure 2B). In contrast to filopodia, 94% of spines were stable over three days, 81% stable over 2 weeks, and 73% stable over one month."