Adaptive encoding of motion information in the fly visual system

Abstract

Adaptation is a ubiquitous mechanism by which sensory cells and neurons match their response properties to the currently prevailing features of their input stimuli. Visual motion-sensitive neurons in the fly brain have been used as a valuable model system for the in vivo analysis of physiological mechanisms underlying neuronal adaptation. In this model system the functional significance of adaptation for visual control of flight movements can be evaluated. Although the effects of adaptation on neuronal sensitivity can in principle be understood as modifications of input-output functions, the exact nature of these changes is often unclear. In this review it is examined in how far the effects of adaptation with different stimulus parameters can be explained by different schemes of adaptation. One important conclusion from studies of adaptation in the fly motion vision system with simple stimulus paradigms as well as with complex, behaviorally generated stimuli is that adaptation improves the sensitivity for novel stimuli during exposure to sustained stimulation. Neuronal adaptation might thus facilitate important tasks such as object detection and obstacle avoidance during flight.