Properties of the Saccadic Eye Movement System Introduction

Publisher Summary The study of saccadic eye movements is currently experiencing a period of enormous fertility, yielding much of interest both for physiologists and for psychologists. The reasons for this are not hard to find. In contrast to most of the motor activity that the body produces that of the eye is subject to very close constraints (three rotational degrees of freedom only) and is also achieved with a constant mechanical load. This renders the oculomotor system amenable to analysis by precise quantitative modelling, and at the level of neurophysiology it is probably true to say that the understanding of the neural networks and channels leading this motor output is at least as good as that of the visual sensory pathways. Even more awe-inspiring is the fact that in many cases it is possible to link these two research areas and, in the case of simple oculomotor reflexes, to trace the whole sensorimotor links and see in detail the ingenious and beautiful systems by means of which the brain achieves its goals. In the case of the saccadic system, this also forms a starting point for the investigation of certain aspects of voluntary activity. Saccadic eye movements in almost all cases represent a co-ordination of both sensory and voluntary factors.