STDP at CA3-CA1 synapses with a single pre-synaptic spike and two post-synaptic spikes (the triplet protocol).

(A) Data reproduced from [19], fit with a difference of Gaussians (least squares fit). refers to time between the pre-synaptic spike and the second post-synaptic spike. (B) An inter-pairing frequency of produced a ‘symmetric’ STDP curve, where a narrow LTP window is shifted in the causal (pre-before-post) direction, surrounded by two latency-dependent LTD windows (solid black). An inter-pairing frequency of 0.5 Hz produced a depression-only curve (dotted grey). The post-synaptic spikes were separated by 10 ms. (C) Mean value of the dynamic time constant for each value of in panel B (corresponding curves).

(A) 数据复刻自文献[19]，采用高斯差分模型进行拟合（最小二乘拟合）。Δt指突触前脉冲与第二个突触后脉冲之间的时间间隔。
(B) 当配对刺激频率为f时，可得到一条“对称”的脉冲时序依赖可塑性（Spike-Timing-Dependent Plasticity, STDP）曲线：其狭窄的长时程增强（Long-Term Potentiation, LTP）窗口沿因果方向（突触前脉冲先于突触后脉冲）偏移，并被两个依赖于潜伏期的长时程抑制（Long-Term Depression, LTD）窗口（黑色实线）所包围。当配对刺激频率为0.5 Hz时，仅得到长时程抑制曲线（灰色虚线）。实验中突触后脉冲之间的间隔为10 ms。
(C) 对应图B中的各条曲线，为不同Δt取值下的动态时间常数τ的平均值。