Figure 1.

Synaptic plasticity induced by intracellular tetanization. A, A scheme of intracellular tetanization experiment. Bursts of short depolarizing pulses (5 ms pulse duration, 5 pulses at 100 Hz; top) were applied through the recording electrode without presynaptic stimulation. The bursts were applied in trains of 10 (1 burst per second; bottom). Intracellular tetanization consisted of three such trains (1 train per minute). Synaptic responses to test stimuli were recorded before and after the intracellular tetanization. B1, B2, Long-term potentiation (B1) and depression (B2) induced by intracellular tetanization at two inputs to the same cell. Blue and red traces show averaged membrane potential responses to small steps of hyperpolarization current and to paired-pulse electric stimuli before (blue) and after (red) the intracellular tetanization. Respective time periods are labeled with blue and red bars between the panels. Time courses show the amplitudes of individual EPSPs evoked by first the first pulse in the paired-pulse stimulation paradigm. Vertical arrows indicate timing of intracellular tetanization. C, Responses to hyperpolarizing current steps and paired synaptic stimulation and time course of EPSP amplitude changes in another input that did not change after intracellular tetanization.