Average synaptic weights as a function of the stimulus interval for STDP with temporal symmetry.

<p>Average synaptic weights for three different connection types: feedforward (squares), feedback (circles) and recurrent (upward triangles) as a function of the stimulus interval after the 20 training trials (a). The amounts of average synaptic modification relative to its initial value 0.5, (b) and (c) for feedforward (b) and feedback (c) connections exhibit exponential falloffs as the stimulus interval increases with exponents (b) and (c), respectively in linear-log scales. we also show the average synaptic weights for the connections including both feedforward and feedback types (downward triangles) in (a). The parameters are the same as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084644#pone-0084644-g002" target="_blank">Fig. 2</a>.