Imagine a fly navigating through a forest at 2 m/s. In order to correct for the effects of the wind and other flight instabilities, the fly must continually estimate its heading direction if only to avoid running into a tree or inadvertently flying in circles. Given the striking prominence of eyes on a fly's body, it is not surprising that vision plays a key role in many of its behaviors, including flight (Egelhaaf and Borst 1993). In fact, when a fly is suspended from a wire inside a rotating drum so that the visual scene in front of the fly moves to the right, the fly uses its wings to turn its body to the right, presumably to try to maintain what it perceives as its current heading direction (Reichardt and Poggio 1976). However, flies do not exhibit this behavior following lesions to subsets of the 50 or so identified neurons in the lobular plate that respond to wide-field visual motion (Hausen and Wehrhahn 1983). The fact that these neurons are involved in stabilizing heading direction, which is critical for chasing potential mating partners and avoiding obstacles, suggests that there has probably been strong evolutionary pressure on their performance. One of these neurons, H1, is particularly accessible experimentally, allowing stable extracellular recordings for hours and even days.