How neuronal morphology impacts the synchronisation state of neuronal networks

Abstract

Neurons can produce a number of qualitatively different spiking dynamics, determined by external conditions like temperature and internal properties such as ion channel composition. The dynamical excitability type can impact the activity of the network, particularly its (de)synchronisation state. Neurons with an onset of spiking via a saddle homoclinic orbit (HOM) bifurcation tend to synchronise inhibitory networks while they organise the spiking activity of excitatory networks into a splay state, where firing phases differ across neurons such that they are regularly distributed in time. Based on mathematical neuron models with dendrites, we here demonstrate that the extent of dendritic arborisation can switch the excitability type to a HOM spiking onset and hence can induce (de)synchronised network states. Our analysis is applicable to a general class of spike-generating neuron models (from ball-and-stick models to anatomically reconstructed neuron models) and highlights the importance of neuronal morphology for the susceptibility of neural tissue to synchronisation in health and disease.