Dynamics of excitable tree networks: Application to sensory neurons*

We study the collective dynamics of diffusively coupled excitable elements on small tree networks with regular and random connectivity, which model sensory neurons with branched myelinated distal terminals. Examples of such neurons include touch receptors, muscle spindles, and some electroreceptors. We developed a theory that predicts the collective spiking activity in the physiologically-relevant strong coupling limit. We show that the mechanism of coherent firing is rooted in the synchronization of local activity of individual nodes, even though peripheral nodes may receive random independent inputs. The structural variability in random tree networks translates into collective network dynamics leading to a wide range of firing rates and coefficients of variations, which is most pronounced in the strong coupling regime.