We computed the steady-state activity of a large-scale model of the granular layer of the rat cerebellum. Within a few tens of milliseconds after the start of random mossy fiber input, the populations of Golgi and granule cells became entrained in a single synchronous oscillation, the basic frequency of which ranged from 10 to 40 Hz depending on the average rate of firing in the mossy fiber population. ... The synchronous, rhythmic firing pattern was robust over a broad range of biologically realistic parameter values and to parameter randomization. Three conditions, however, made the oscillations more transient and could desynchronize the entire network in the end: a very low mossy fiber activity, a very dominant excitation of Golgi cells through mossy fiber synapses (rather than through parallel fiber synapses), and a tonic activation of granule cell GABAA receptors (with an almost complete absence of synaptically induced inhibitory postsynaptic currents). The model predicts that, under conditions of strong mossy fiber input to the cerebellum, Golgi cells do not only control the strength of parallel fiber activity but also the timing of the individual spikes. Provided that their parallel fiber synapses constitute an important source of excitation, Golgi cells fire rhythmically and synchronized with granule cells over large distances along the parallel fiber axis. See paper for more and details.
Model Type: Realistic Network
Region(s) or Organism(s): Cerebellum
Cell Type(s): Cerebellum interneuron granule GLU cell
Currents: I Na,t; I L high threshold; I A; I K; I h; I K,Ca
Model Concept(s): Oscillations; Synchronization; Simplified Models
Simulation Environment: GENESIS (web link to model)
Implementer(s): Maex, Reinoud [reinoud at bbf.uia.ac.be]
References:
Maex R, De Schutter E. (1998). Synchronization of golgi and granule cell firing in a detailed network model of the cerebellar granule cell layer. Journal of neurophysiology. 80 [PubMed]