Fig. 1.
Synaptic depression in principal neurons of the rat MNTB. A, An example of EPSCs elicited by afferent fiber stimulation trains of 30 stimuli at 0.5 Hz. Voltage-clamp recordings were made at a holding potential of −80 mV in 2 mm [Ca]o and 1 mm[Mg]o. Note that the first EPSC in the train is the largest and that the onset of the EPSCs was ≈1.5 msec after the stimulus artifact. B, In the same cell as inA, EPSCs were elicited by 30 stimuli at 10 Hz.C, The peak EPSC amplitude of examples Aand B are plotted for 0.5 Hz (open symbols) and 10 Hz (closed symbols). These AMPA receptor-mediated EPSCs depressed from the initial amplitude (I0) to a new steady-state value (Iss), which was obtained from the steady-state value of an exponential fit (solid line; τ = 2.47 sec for 0.5 Hz and τ = 159 msec for 10 Hz).