Nonlinear shunting model of the pupil light reflex.

A leaky-integrator equation with shunting is introduced to represent processing at the retinal level as part of a system of delay-differential equations modelling the pupil light reflex. This system of equations exhibits the correct behaviour in response to monocular and binocular sinusoidal inputs. Understanding such behaviour can help to establish (non-invasively) the location and nature of nonlinearities in the reflex arc and how signals from the two eyes combine.