ELSC Seminar Series

The distribution of preferred phases of whisking neurons in the somatosensory system of rats and mice presents a conundrum: simple models predict distributions that are an order of magnitude narrower than empirically observed. Thus, it remains unclear which mechanism generates this unexplained distribution. We studied the hypothesis that the unexplained distribution of preferred phases in the whisker system results from spike timing dependent plasticity (STDP), and explored STDP dynamics in the framework of a modeling study. Our investigation reveals that under a wide range of parameters, STDP dynamics does not converge to a fixed-point. Rather, the synaptic weights continue to evolve in time. As a result, the preferred phases of the downstream population drift in time at a non-uniform velocity, which in turn induces a non-uniform distribution of preferred phases. In this manner, the distribution results from the continuous remodeling of synaptic efficacies. Thus, our theory can account for the distribution of preferred phases as well as for drifting representations – even in the noiseless limit, and provides several empirical predictions.