Keegan Keplinger, Department of Applied Mathematics, University of Waterloo
Switching dynamics of the Aplysia bag cell neuron
The bag cell neuron clusters of the sea slug Aplysia act as a master switch for a chain of downstream peptide signals that are relevant to reproduction. Given a sufficient stimulus, a single bag cell neuron can be excited from a rest state to a persistent oscillatory state called the afterdischarge. The oscillatory state is ultimately transient, eventually leading to a refractory period whereby excitation to an oscillatory state becomes temporarily impossible. Regulation of afterdischarge behavior depends on the action of second messenger systems within the bag cell neuron. The details of such second messengers remain unclear, but major players, such as calcium, calmodulin, protein kinase A, and protein kinase C have been indicated in the transition from excitatory dynamics to persistent oscillatory spiking, as well as suppression of oscillations during the refractory period. Through collaboration with experimentalists, the objective of this research project is to build a single bag cell neuron model, complete with second-messenger dynamics and couple it to a network of similarly constructed neurons to reproduce the dynamical switching behavior of the bag cell neuron clusters.