Reconstruction of neural control signals for saccades based on an inverse method

Abstract

The failure to obtain realistic saccadic velocity profiles, in earlier simulation studies using a linear oculomotor plant model and a stylized pulse-step input, has led to the development of quite complex plant models. The stylized-input assumption has later been shown to be unrealistic: it is known now that the pulse has a smooth shape in which the decay period is longer than the rising edge. To explore the applicability of linear models without imposing a priori constraints on the shape of the control signal, we have used Fourier deconvolution for reconstructing the neural-control signal. From the results obtained with this inverse method, we conclude that it is not necessary to use a complicated model in order to obtain realistic saccade velocity profiles. Furthermore, the results illustrate clearly that a second order linear plant model necessitates active braking at the input in order to explain the occurrence of short-lasting saccades.