Computational modelling of speed microcircuits in larval zebrafish spinal cord with SiliFish.

Abstract

Larval zebrafish display various types of swimming behaviours that require a wide range of tail beat frequencies (TBF). Experimental data strongly suggest that these TBF ranges are generated by different speed microcircuits within the spinal cord assembled by neurons arising from different neuronal populations. How these different microcircuits generate different swimming speeds and interact with other microcircuits is not well understood. To gain a better understanding of the organizations and roles of the speed microcircuits, we developed a computational model informed by previous studies of zebrafish spinal speed microcircuits, using a software tool we developed for modelling spinal circuits for swimming. The model we created had slow, intermediate, and fast-speed microcircuits that were able to generate different TBF ranges as reported. We were also able to replicate several experimental findings on spinal neurons for zebrafish swimming to support the validity of the model. Our simulation suggests that the intrinsic properties of the neurons and their connectivity led to the activation of specific speed circuits that were embedded within the whole spinal cord model.