title: A positive feedback at the cellular level promotes robustness and modulation at the circuit level.
abstract: This article highlights the role of a positive feedback gating mechanism at the cellular level in the robustness and modulation properties of rhythmic activities at the circuit level. The results are presented in the context of half-center oscillators, which are simple rhythmic circuits composed of two reciprocally connected inhibitory neuronal populations. Specifically, we focus on rhythms that rely on a particular excitability property, the postinhibitory rebound, an intrinsic cellular property that elicits transient membrane depolarization when released from hyperpolarization. Two distinct ionic currents can evoke this transient depolarization: a hyperpolarization-activated cation current and a low-threshold T-type calcium current. The presence of a slow activation is specific to the T-type calcium current and provides a slow positive feedback at the cellular level that is absent in the cation current. We show that this slow positive feedback is required to endow the network rhythm with physiological modulation and robustness properties. This study thereby identifies an essential cellular property to be retained at the network level in modeling network robustness and modulation.
authors: Department of Electrical Engineering and Computer Science, University of Liège, Liège, Belgium; Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey;
authors: Julie
authors: J
authors: Dethier
authors: Department of Electrical Engineering and Computer Science, University of Liège, Liège, Belgium; Laboratory of Pharmacology and GIGA Neurosciences, University of Liège, Liège, Belgium; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts; and.
authors: Guillaume
authors: G
authors: Drion
authors: Department of Electrical Engineering and Computer Science, University of Liège, Liège, Belgium; Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
authors: Alessio
authors: A
authors: Franci
authors: Department of Electrical Engineering and Computer Science, University of Liège, Liège, Belgium; Department of Engineering, University of Cambridge, Cambridge, United Kingdom r.sepulchre@eng.cam.ac.uk.
authors: Rodolphe
authors: R
authors: Sepulchre
mesh_terms: D000818:Animals; D003386:Brachyura; D020747:Calcium Channels, T-Type / Q000378:metabolism*; D003198:Computer Simulation; D025461:Feedback, Physiological / Q000502:physiology*; D017952:Ganglia, Invertebrate / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology*; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D010507:Periodicity
chemical_list: D020747:Calcium Channels, T-Type
keywords: central pattern generators; modulation; networks; postinhibitory rebound; robustness