A biophysical model explains the oscillatory behaviour of immature starburst amacrine cells

Dora Karvouniari (1) , Lionel Gil (2) , Olivier Marre (3) , Serge Picaud (3) , Bruno Cessac (1)

1 BIOVISION - Biologically plausible Integrative mOdels of the Visual system : towards synergIstic Solutions for visually-Impaired people and artificial visiON
2 INLN - Institut Non Linéaire de Nice Sophia-Antipolis
3 Institut de la Vision

During early development, waves of activity propagate across the retinal surface, and play a key role in the proper wiring of the early visual system. How these waves are generated by the retinal network though is still unclear. During stage II retinal waves, Starburst Amacrine Cells (SACs) exhibit an intrinsic rhythmic bursting behaviour , triggering waves of activity across the retinal surface. While several models have tried to reproduce retinal waves, none of them reproduces the rhythmic bursting of individual SACs. Here, we propose a biophysical model which reproduces certain intrinsic properties of immature bursting starburst amacrine cells. We perform a bifurca-tions analysis to identify the key mechanisms explaining the bursting behaviour of SACs and isolate two essential biophysical parameters controlling it; the potassium conductance gK and the rest membrane potential VL. This model also explains how different species can exhibit variable interburst intervals, as observed experimentally. Finally, our model provides a testable experimental prediction about the expression of voltage-dependent potassium channels along development and their role on the excitability properties of immature starburst amacrine cells.

Domaines: Science non linéaire [physics]; Biophysique; Neurosciences

Dora Karvouniari, Lionel Gil, Olivier Marre, Serge Picaud, Bruno Cessac. A biophysical model explains the oscillatory behaviour of immature starburst amacrine cells. 2017. ⟨hal-01484133v1⟩