Figure 8.

A possible model to explain the increment in the α exponent following α-LTX and LTP. (A) A cartoon representing the present model of synaptic vesicle exocytosis with a reserve and a recycling pool of vesicles. Black triangles on the membrane refer to docking or release sites (N). In this model recycling vesicles should freely diffuse in the cytosol until they bind to docking sites to be released (T_diff is the average time to reach the docking site). Spontaneous fusion would occur after a random period of residence at the docking sites (T_fus is the average time to have the release of a docked vesicle). If in control conditions release probability is very low then T_fus ≫ T_diff, then the Brownian dynamics of recycling vesicles diffusion inside the synaptic cytosol would not sensibly affect the timing of spontaneous exocytosis. (B,C) Conditions increasing release probability to high (panel B, α-LTX) or intermediate (panel C, LTP) levels would make the transfer of the 1/f dynamics more efficient because T_fus would approach or even go below the value of T_diff.