The mode-sensing hypothesis: Matching sensors, actuators and flight dynamics

Abstract

Here we elaborate upon the recent hypothesis that the sensory systems of insects are matched to their flight dynamics, such that they are configured to make or encode measurements within a modal coordinate system. This hypothesis is inspired by several distinctive organizational principles of insect sensory systems: namely, that insects appear to be configured a) to sense relative, rather than absolute, quantities; b) to make measurements in highly non-orthogonal axis systems; and c) to fuse sensory inputs from different modalities prior to using them as feedback to the actuators. Having elaborated upon the hypothesis itself and considered the functional advantages of the resulting control architecture, we discuss some of the physiological details of how the requisite coordinate systems might in practice be set up in the fly visual system. We also provide a mathematical framework for testing the quantitative match between sensory system and flight dynamics in the specific context of the visual systems of flies.