We investigated patterns of spontaneous neuronal activity in mouse accessory olfactory bulb mitral cells, the direct neural link between vomeronasal sensory input and limbic output. Both in vitro and in vivo, we identify a subpopulation of mitral cells that exhibit slow stereotypical rhythmic discharge. In intrinsically rhythmogenic neurons, these periodic activity patterns are maintained in absence of fast synaptic drive. The physiological mechanism underlying mitral cell autorhythmicity involves cyclic activation of three interdependent ionic conductances: subthreshold persistent Na(+) current, R-type Ca(2+) current, and Ca(2+)-activated big conductance K(+) current. Together, the interplay of these distinct conductances triggers infraslow intrinsic oscillations with remarkable periodicity, a default output state likely to affect sensory processing in limbic circuits. The model reproduces the intrinsic firing in a reconstructed single AOB mitral cell with ion channels kinetics fitted to experimental measurements of their steady state and time course.
Model Type: Neuron or other electrically excitable cell
Region(s) or Organism(s): Olfactory bulb
Cell Type(s): Olfactory bulb (accessory) mitral cell
Currents: I Potassium; I Na,p; I Calcium; I Na,t; I K,Ca; I A; I K; I R
Model Concept(s): Sensory processing; Oscillations; Olfaction
Simulation Environment: NEURON
Implementer(s): O'Connor, Simon [simon.oconnor at btinternet.com]
References:
Gorin M et al. (2016). Interdependent Conductances Drive Infraslow Intrinsic Rhythmogenesis in a Subset of Accessory Olfactory Bulb Projection Neurons. The Journal of neuroscience : the official journal of the Society for Neuroscience. 36 [PubMed]