Advanced memristive model of synapses with adaptive thresholds

In this paper, we propose a memristive STDP model realizing the principle of suppression of Froemke and Dan for triplet spikes. The proposed model claims compatibility with both the pair and triplet STDP rules, going beyond the limit of the basic memristive STDP model. The compatibility is realized by assuming a mechanism of variable thresholds adapting to synaptic potentiation (LTP) and depression (LTD): the preceding LTP has a negative influence on the following LTD. The corresponding dynamical process is governed by a set of ordinary differential equations. It is an equivalent model of the original suppression STDP model. A relation of the adaptive thresholds to short-term plasticity is addressed.