A Survey of Eye Movements

This chapter reviews the visual requirements, properties, and neural substrate of eye movements and the advantages they offer to clinicians and scientists. Eye movements are easily observed, measured, and classified by the way they serve vision. The relationship between eye rotations and extraocular motoneuron discharge is approximately linear, making it possible to study how networks of neurons temporally integrate raw sensory signals. Gaze-holding vestibular eye movements act at short latency to guarantee clear vision during natural head movements. Gaze-shifting saccades, pursuit, and vergence movements are concerned with pointing each eye’s line of sight (fovea) at features of interest in the environment. By combining ingenious experimental design with functional imaging and electrophysiology, it has become possible to understand much about the neural substrate underlying each class of eye movements. Consequently, eye movements have become powerful tools to study cognition and memory, adaptation and motor learning, as well as aiding topological diagnosis.