Figure 4

Schematic illustration of modelling procedure. (a) A series of boxcar models simulate the magnitude of the spatial offset during adaptation, de-adaptation, and test periods. (b,c) Illustration of convolving an example boxcar (Adapt 32 s condition) with exponential functions (leaky integrators). (b) Example of single-exponential modelling procedure: a single leaky integrator is convolved with the boxcar, and the resulting output gives a prediction for the time course of the VAE. (c) Example of multiple-exponential modelling procedure: two leaky integrators with longer and shorter trial-constants respectively are each convolved with the boxcar in turn, and the summed output of both mechanisms provides a prediction for the time course of the VAE. In all cases, the procedure is then repeated for the remaining boxcars/adaptation conditions. Model parameters are optimised via maximum likelihood estimation to minimise the prediction error during the test periods across all conditions simultaneously.