Resurgent Na+ Current Offers Noise Modulation in Bursting Neurons

Abstract

Uncertainties pose an ongoing challenge for information processing in the nervous system. It is not entirely clear how neurons maintain dynamic stability of information, encoded in the temporal features of spike trains, notwithstanding stochastic influences. Here we examined the contribution of subclasses of membrane sodium currents in real-time noise modulation in sensory neurons. Fast sodium (Na+) currents are essential for spike generation, and a persistent Na+ current can entrain preferred input frequencies via membrane resonance. Using mathematical modeling, theory and experiments, we show that a resurgent Na+ current can stabilize the temporal features of burst discharge and confer noise tolerance. These novel insights reckon the role of biophysical properties of Na+ currents beyond mere spike generation. Instead, these mechanisms might be how neurons perform real-time signal processing to maintain order and entropy in neural discharge. Our model analysis further predicts a negative feedback loop in the molecular machinery of an underlying Nav1.6-type Na+ channel gating considered in this study.