From Cold-Sensing to Rhythm-Generating Neurons: Dynamical Mechanisms of the Spectrum of Spiking, Bursting, and Episodic Activities

The ability of neural circuits to generate diverse patterns of electrical activity — from tonic spiking to bursting and episodic rhythms — underlies the full range of behaviors from sensory perception to locomotion and homeostatic regulation, yet the principles unifying these patterns across distinct circuit types have remained elusive. Here we show that a conserved set of ionic and neuromodulatory dynamical mechanisms governs transitions across this full spectrum, from peripheral cold-sensing nociceptors to rhythm-generating central pattern generators. The interplay of fast and slow ionic current dynamics alongside shifts in intracellular and extracellular concentrations of Ca²⁺, Cl⁻, and Na⁺ produces the rich repertoire of neural activities, with neuromodulation shifting circuits between regimes while conferring robustness against ionic perturbations. These findings reveal that sensory coding and rhythmic motor control share deep mechanistic principles of burst generation and episodic activity, with implications for understanding how nervous systems maintain functional rhythms under changing physiological conditions.