Fig. 11.

Assessing synaptic independence.A, Peak AMPA receptor P_openas a function of distance under a variety of conditions: a single vesicle with no uptake (solid; ctrl), with uptake (25 μm transporters; dotted,uptake), three vesicles (with 25 μmtransporters; dot-dashed, 3 vesicles), and with obstructions to diffusion in the synaptic cleft (α_cleft = 0.7, λ_cleft = 1.3; one vesicle with 25 μm transporters; dashed,obstructed). The average peak synapticP_open values are represented by thehorizontal line segments in the top leftcorner of the graph. The synaptic responses in descending order are: 3 vesicles, obstructed, ctrl ≈ uptake. B, Analogous plot for NMDA receptors. Same key as in A.C, The P_open curves fromB for NMDA receptors are replotted (left axis; same key as in A) after normalization to the average synaptic P_open in each condition (horizontal line segment top left). Two probability density functions (lightly dotted lines) for the distance to the nearest neighbor synapse are plotted (right axis) and labeled with the corresponding densities:N_v = 3.5 synapses μm⁻³ or N_v = 1.25 synapses μm⁻³. nnd, Nearest neighbor distance.