“…In adult animals, these
substrates can reversibly remodel or turnover during short intervals of days to
weeks as a result, eg, of extensions/retractions of axonal branches and
boutons, 27–29 spines and
dendrites, 30–33 and glial
processes, 34–36 over
distances of a few micrometers for spines, 37 and several, tens, or more micrometers for cell processes. 27,35,38,39 Turnover
can also include cell loss, angiogenesis, 40,41 gliogenesis, 42,43 and fluxes
in volumes of cells 44,45 and intravascular and extravascular spaces. 46,47 Given
these ongoing changes and high substrate densities, related thickness
fluctuations are arguably quite plausible.…”