Figure 2

Changes in eEPSCs are predicted by changes in mEPSC properties. A, B, Hypothetical distributions of two measures of variability of evoked synaptic responses, the coefficient of variation (CV) and the Fano factor (FF), are illustrated with black lines. The red lines illustrate shifts in these distributions as a result of changes in quantal parameters p, q, or n indicated in the boxes. C, Proxy distributions for the CV of an evoked synaptic response, a measure independent of quantal amplitude q. Distributions are generated using unitary synaptic connections built from experimental measurements of quantal parameters at single boutons (Nauen and Bi, 2012), along with changes in mEPSC properties measured in Figure 1. D, Same as C, but for the FF, a measure independent of bouton number n. E, Measured distribution of the CV, taken from repeated measurements of eEPSCs recorded in pairs of neurons here. Each plotted point is obtained from the responses at one unitary connection. F, Same as E, but for the FF. Distributions in E and F are not significantly different from those predicted in C and D, respectively (p > 0.2, KS test).