Spindle oscillations emerge at the critical state of electrically coupled networks in the thalamic reticular nucleus

Spindle oscillation is a waxing-and-waning neural oscillation observed in the brain, initiated at the thalamic reticular nucleus (TRN) and typically occurring at 7–15 Hz. Experiments have shown that in the adult brain, electrical synapses, rather than chemical synapses, dominate between TRN neurons, suggesting that the traditional view of spindle generation via chemical synapses may need reconsideration. Based on known experimental data, we develop a computational model of the TRN network, where heterogeneous neurons are connected by electrical synapses. The model shows that the interplay between synchronizing electrical synapses and desynchronizing heterogeneity leads to multiple synchronized clusters with slightly different oscillation frequencies whose summed-up activity produces spindle oscillation as seen in local field potentials. Our results suggest that during spindle oscillation, the network operates at the critical state, which is known for facilitating efficient information processing. This study provides insights into the underlying mechanism of spindle oscillation and its functional significance. [Display omitted] •TRN neurons show heterogeneity and are connected by electrical synapses•Electrical synapses and heterogeneity shape network dynamics via competition•Spindle oscillations emerge when the TRN network reaches the critical state Li et al. present a computational model describing how heterogeneous TRN neurons connected via electrical synapses generate spindle oscillations. In this model, electrical synapses and neuronal heterogeneity interact to drive the network toward the critical state, where the superposition of neuronal activities produces the characteristic waxing-and-waning spindle oscillations.