Figure 2.

Dynamics of potentiation of interconnections between T-stellate cells illustrated in a dual recording. a, When the presynaptic cell was caused to fire, no EPSCs were observed postsynaptically. b, After pairing of presynaptic firing with postsynaptic depolarization for 36 s (*), EPSCs of approximately uniform amplitude appeared. c, After the EPSCs faded, the postsynaptic cell was depolarized again for a longer period, 72 s (**). After the postsynaptic voltage was returned to rest, EPSCs occurred more frequently than before. d, Time course of this experiment summarized in the plot of the frequency and amplitude of EPSCs as a function of time. Pairing presynaptic firing and postsynaptic depolarization evoked EPSCs whose frequency (red symbols) waned over ∼2 min. A longer pairing (72 s) evoked more EPSCs that remained potentiated for 2 min and then faded over the next 2 min. The amplitude of EPSCs remained constant throughout the experiment.