Abstract
The functional properties of cerebellar stellate cells and the way they regulate molecular layer activity are still unclear. We have measured stellate cells electroresponsiveness and their activation by parallel fiber bursts. Stellate cells showed intrinsic pacemaking, along with characteristic responses to depolarization and hyperpolarization, and showed a marked short-term facilitation during repetitive parallel fiber transmission. Spikes were emitted after a lag and only at high frequency, making stellate cells to operate as delay-high-pass filters. A detailed computational model summarizing these physiological properties allowed to explore different functional configurations of the parallel fiber—stellate cell—Purkinje cell circuit. Simulations showed that, following parallel fiber stimulation, Purkinje cells almost linearly increased their response with input frequency, but such an increase was inhibited by stellate cells, which leveled the Purkinje cell gain curve to its 4 Hz value. When reciprocal inhibitory connections between stellate cells were activated, the control of stellate cells over Purkinje cell discharge was maintained only at very high frequencies. These simulations thus predict a new role for stellate cells, which could endow the molecular layer with low-pass and band-pass filtering properties regulating Purkinje cell gain and, along with this, also burst delay and the burst-pause responses pattern.
Highlights
The functional properties of cerebellar stellate cells and the way they regulate molecular layer activity are still unclear
Given that a full characterization of all the relevant mechanisms is unavailable at the moment, a first hypothesis on stellate cell role could be generated through computational modeling, which can synthesize morpho-electrical information in a coherent rule-based framework (e.g. see the case of granule cell (GrC), Golgi cells and Purkinje cells (PCs), just to remain in the cerebellum)[28,29,30,31,32,33,34,35]
Detailed models of SCs of mouse cerebellum were generated starting from morphological reconstructions and using electrophysiological recordings as a template for the optimization of membrane m echanisms[34,35]
Summary
The functional properties of cerebellar stellate cells and the way they regulate molecular layer activity are still unclear. When reciprocal inhibitory connections between stellate cells were activated, the control of stellate cells over Purkinje cell discharge was maintained only at very high frequencies These simulations predict a new role for stellate cells, which could endow the molecular layer with low-pass and band-pass filtering properties regulating Purkinje cell gain and, along with this, burst delay and the burst-pause responses pattern. We have measured SCs electroresponsiveness and their activation by parallel fiber (PF) bursts with the aim of generating precise models, which had been used to explore the computational impact of these neurons on Purkinje cells (PCs). Given that a full characterization of all the relevant mechanisms is unavailable at the moment, a first hypothesis on stellate cell role could be generated through computational modeling, which can synthesize morpho-electrical information in a coherent rule-based framework (e.g. see the case of granule cell (GrC), Golgi cells and PCs, just to remain in the cerebellum)[28,29,30,31,32,33,34,35]
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