A major focus of my research concerns the neurophysiological basis of visual processing, in particular those parts of the brain involved in the processing of
optic flow that results from self-motion. Because the world consists of stationary objects and surfaces, self-motion through the environment induces patterns of motion across the entire retina, known as optic flow.
Optic flow provides a rich source of proprioceptive information, and can be used for several behaviors including determination of heading, control of posture and locomotion, perception of self-motion and navigation.
Optic flow is analyzed by two specific visual pathways, a pretectal pathway and the Accessory Optic System (AOS), and is integrated with vestibular information in the vestibulocerebellum (VbC). We know that the these pathways to the cerebellum are critical for controlling the optomotor or optokinetic response. The optokinetic response is ubiquitous to the animal kingdom and can be demonstrated in both vertebrates and invertebrates. Gaze stabilization is critical for normal visual function: without gaze stabilization visual acuity is dramatically impaired as is velocity discrimination. Damage to the AOS and pretectum, but not other visual pathways, severely compromises or even abolishes the optokinetic response. Most of my work has shown that the nucleus of the basal optic root (nBOR) in pigeon AOS, the pretectal nucleus lentiformis mesencephali (LM) and the VbC, form channels that are specialized for processing particular patterns of optic flow that result from either self-rotation or self-translation.