Does spike firing rate dependence imply rate coding?

Rate coding of information assumes frequency-dependent changes in synaptic efficiency. While this concept is widely accepted, current electrophysiological data have not validated it conclusively since they mix pre- and postsynaptic contributions. We study whether frequency-dependent plasticity inherently supports rate coding by comparing four STDP models under a novel stimulation protocol. Our results show that only the STRDP model and the triplet STDP with synaptic forgetting yield learning of rate-codded information, while classical STDP does not. Thus, our model findings suggest that new experiments designed to decouple pre and postsynaptic activities are essential to resolve the debate.