Figure 2.

Decay kinetics of facilitation in the predepressed state of the synapse. A, The EPSC in response to a paired-pulse protocol that consisted of a 10 Hz train of 10 stimuli to predepress the synapse, followed by an 11th stimulus given at variable interpulse intervals (5–100 ms). B, The EPSC traces during the last stimulus at 10 Hz and during five different interstimulus intervals following the 10 Hz trains are shown at a higher time resolution (corresponding to the boxed area in A). C, Average paired-pulse ratio (PPR; peak EPSC 11/peak EPSC 10) following the 10 Hz conditioning train (filled symbols) and for control conditions without preceding stimulation (open symbols). The decay of facilitation in the predepressed state (filled symbols) was fitted with an exponential function with a time constant of 38 ms (dashed line). Data in A–C are from the same cell. D, Mean decay time constant of facilitation recorded from n = 6 cells. E, Average paired-pulse ratio (Δt = 10 ms) in response to two stimuli applied under control conditions (open bar, no preceding stimulation) or following the conditioning (cond.) 10 Hz train (gray bar). Note the significantly different paired-pulse ratio following 10 Hz trains (p = 0.0015; n = 7 cells).