Meeting Abstract

85.5  Monday, Jan. 6 11:15  Motion Perception of Composite Patterns in Fruit Flies CURREA, J; Florida International University jcurr001@fiu.edu

Reliably detecting visual motion in a natural environment is an important survival trait for many animals, but a computationally difficult problem. Despite a radically different eye structure, insects are a surprisingly useful model for human motion perception. For example, they detect and respond to both first- and second-order motion, flying with patterns in a way analogous to human eye tracking. However, here we show that in the important stimulus category of plaids, or composite drifting sinusoidal gratings, fruit fly tracking diverges from human perception. Tethered flies tend to steer to follow motion in front of them, consistent with minimizing retinal slip, or correcting for unintended flight deviations. We overlaid pairs of drifting sinusoidal gratings and displayed them to the frontal visual region of rigidly tethered flying fruit flies, and tracked their steering responses. Plaids have the property that when viewed through an aperture, there is no way to discriminate two sinusoids moving independently from a fixed single pattern moving in a different direction, called the rigid direction. We constructed several common plaids in which humans and flies perceive opposite directions of motion, humans tracking the rigid direction and flies steering approximately to the vector sum of the sinusoids. This may result from the computational limits of fruit fly brains, or different adaptive strategies between humans and flies.