The Detection and Analysis of Optic Flow by Crabs: from Eye Movements to Electrophysiology

Abstract

Although the nature of the retinal image motion that results from an animal’s own movements was first described 50 years ago (Gibson 1950), studies of how this optic or visual flow field is analysed and used by animals is much more recent. Much of this research has been carried out on arthropods, birds and primates. It has received considerable impetus from the discovery of neurones sensitive to optic flow in the macaque monkey (Tanaka and Saito 1989; Duffy and Wurtz 1991), in pigeons (Wylie and Frost 1993) and in flies (Hausen 1993; Krapp and Hengstenberg 1996). The field has generated exciting new data both on the detection of optic flow by visual interneurones, and the way in which animals use the information about their own movements and the layout of their surroundings that the optic flow field provides (Lappe 2000). Within the Crustacea, research in this area has been particularly important in demonstrating the importance of eye movements in the analysis of optic flow (Barnes and Nalbach 1993; Blanke et al., 1997; Nalbach and Nalbach 1987).