The theory complements our earlier work, which developed extensions to cable theory for the micro-scale equations of neural stimulation that apply to individual fibres. The modelling framework provides a number of advantages over other approaches currently adopted in the literature and, therefore, can be used to accurately estimate the membrane potential generated by extracellular electrical stimulation.

The unique features of the composite model and its simplified versions can be used to accurately estimate the spatio-temporal response of neural tissue to extracellular electrical stimulation.

Significant differences exist between cortical responses to stimulation of healthy and degenerate retinae. Our results highlight the importance of using a retinal degeneration model when evaluating the efficacy of novel stimulation paradigms.

In models of electrical stimulation of the retina, somata are typically represented either as several compartments or just a single compartment. When stimulated by a subretinal or suprachoroidal prosthesis, the soma polarizes within a microsecond after the application of extracellular field, whereas neurites polarize at a slower rate. We describe an idealized model that compares these two mechanisms conceptually, and a biologically plausible model that places the two mechanisms in the context of a morphologically and biophysically detailed retinal ganglion cell. Two versions of the latter model are compared, which differ only in the number of compartments used to represent the soma. Simulation results show that predicted thresholds may be lower by as much as 70% when using a multicompartment soma rather than a single-compartment one.