Fly Flight Simulator to Study Visual and Rotational Stimuli
John Bender, Michael Dickinson, Pietro Perona

The fly flight arena was designed (not by me!) to explore the connections between the different sensory modalities that fruit flies use to control their flight. The fly is glued to a metal post mounted in the center of a cylindrical arena. The walls of this cylinder are made out of 11,340 LEDs which are controlled in real time by a computer. (Flies have poor spatial resolution, estimated at 5°, but very fast temporal resolution - around 200 Hz. Human vision has spatial resolution of about 1/30th degree and temporal resolution around 20 Hz.) (full report)

Visuo-olfactory sensory fusion for flight behavior in flies
Mark Frye, Michael Dickinson

Over the past year I have used the support of this grant to study the neurobiological basis of multisensory flight control in flies. I have specifically focused on vision and olfaction and how feedback from these sensory modalities is integrated to coordinate complex spatiotemporal dynamics of search behaviors. Using a state-of-the-art stereo video system, I tracked freely flying flies within different sensory landscapes and found that visual expansion cues generated as flies approach vertical edges is required for odor localization (Fig. 5A). Using a 'virtual reality' tethered flight simulator, I examined the fine scale motor responses to visual expansion, odor, and both presented simultaneously. Our results show that during flight sensorimotor responses to odor are linearly superimposed upon visual responses (Fig. 5B). This is a remarkable finding because it suggests that – from an engineering perspective - the underlying neural processing for tracking multiple sensory cues is relatively simple. A parallel sensory-to-motor control architecture may be an evolutionary adaptation that imparts both the extraordinary flexibility and robustness exhibited by flies in diverse sensory landscapes. These results have culminated in one publication, presentations at two international meetings, and two more manuscripts to be submitted for publication this month. (full report)

Modular Electronics for Rapid Development of Behavioral Stimuli
Michael Reiser, Michael Dickinson

Whereas flies use many sensory modalities, most of the behaviors we casually observe are dominated by visual control. For this reason, presenting controlled visual environment to tethered flies continues to be a powerful experimental paradigm. Most experiments have been done in simple arenas, either patterns attached to a rotating drum, or in recent years, using cylinders covered with LEDs. Conventional display technologies (LCDs, CRTs, etc.) can not be used as stimuli for insect experiments, because their refresh rates are typically several times slower than the flicker fusion rate of insect visual systems. LEDs are used because they can be rapidly refreshed, which is necessary to maintain the illusion of motion. We have designed modular panels of 64 LEDs each, which can be snapped together to ‘tile’ an experimental environment with controllable displays. The panels are individually addressed and communicated with via a rapid serial interface. The panels have been designed to be extremely bright (with the added flexibility of individual pixel programmable brightness control), allowing experimentation over a broad range of behaviorally relevant stimuli conditions. The panels are controlled via a microprocessor controller which, for most experiments, will not require a computer in the loop, significantly reducing the infrastructure necessary for experiments. This technology allows an experimenter to build a visual arena with a customized geometry in a matter of hours.
(full report)

Vision as a Compensatory Mechanism for Disturbance Rejection in Upwind Flight
Michael Reiser, Michael Dickinson, Sean Humbert, Richard Murray

For several decades the visuo-motor control system of flies has been extensively studied. However, recent results have cast new light on many long standing assumptions about the operation of the flight control system. In this project we seek to demonstrate that through a faithful model of the fly's behavior, it is possible to provide some context within which controlled behavioral assays can be interpreted. (full report)

A Biosphere for Studying Neural Circuits of Drosophila melanogaster
Jasper Simon, Michael Dickinson

Research Proposal. Observation rather than experimentation dominates the study of animal behavior, a limit to our understanding. We require the ability to study behavior while aspects of an animal's environment can be controlled. To meet this goal, I plan a biosphere in which I can control various parameters to recapitulate the pertinent aspects of an animal's natural environment.

Seasonal change and undesirable habitats force animals to assess local resources and decide between to stay or to move somewhere potentially more desirable. Cues from both the environment and an animal's current internal state influence such decisions. What mechanisms underlie the ability to integrate and process these cues? Is movement directed simply by cue saliency? Or do animals carry out some rudimentary cost-benefit analysis?

Within a neuroethological context, resource leaving in the fruit fly Drosophila melanogaster provides a useful model to study such elementary decision making. With the molecular tools available in Drosophila, I propose to study the neural circuits involved in this process.

Neurogenetic Dissection of Resource Choice in the Fruit Fly Drosophila melanogaster
Jasper Simon, Michael Dickinson

Abstract. I propose to study the neurogenetic mechanisms that underlie resource choice in the fruit fly Drosophila melanogaster. Specifically, how do genes regulate the decision to leave resources? In natural environments the distribution and abundance of resources vary over space and time—quite scarce during certain times in the life of a fly. Thus, it seems flies would stay indefinitely on an established resource, but casual observation proves this false. At various times scales: moment-to-moment, over the course of a day, or throughout a lifetime, flies leave resources. What external and internal cues influence the probability to leave? How do these cues interact? Moreover, this behavior initiates dispersal and has implications for the animal’s life history. Within a neuroethologcal context, resource leaving in flies provides a useful model to study elementary decision-making in a simple nervous system. I aim to characterize, identify, and define the relative contribution of external sensory cues, internal state cues, and their interactions in the determination of resource choice. Using molecular and population genetic approaches, I will attempt to identify the neuronal circuits and genes that participate in the regulation of resource choice.