Active antennal movements in Drosophila can tune wind encoding.

Insects use their antennae to smell odors, detect auditory cues, and sense mechanosensory stimuli such as wind and objects, frequently by combining sensory processing with active movements. Genetic access to antennal motor systems would therefore provide a powerful tool for dissecting the circuit mechanisms underlying active sensing, but little is known about how the most genetically tractable insect, Drosophila melanogaster, moves its antennae. Here, we use deep learning to measure how tethered Drosophila move their antennae in the presence of sensory stimuli and identify genetic reagents for controlling antennal movement.

Encoding of Wind Direction by Central Neurons in Drosophila.

Wind is a major navigational cue for insects, but how wind direction is decoded by central neurons in the insect brain is unknown. Here we find that walking flies combine signals from both antennae to orient to wind during olfactory search behavior. Movements of single antennae are ambiguous with respect to wind direction, but the difference between left and right antennal displacements yields a linear code for wind direction in azimuth.

Algorithms for Olfactory Search across Species.

Localizing the sources of stimuli is essential. Most organisms cannot eat, mate, or escape without knowing where the relevant stimuli originate. For many, if not most, animals, olfaction plays an essential role in search.

An Array of Descending Visual Interneurons Encoding Self-Motion in Drosophila.

Unlabelled: The means by which brains transform sensory information into coherent motor actions is poorly understood. In flies, a relatively small set of descending interneurons are responsible for conveying sensory information and higher-order commands from the brain to motor circuits in the ventral nerve cord. Here, we describe three pairs of genetically identified descending interneurons that integrate information from wide-field visual interneurons and project directly to motor centers controlling flight behavior.

Octopaminergic modulation of the visual flight speed regulator of Drosophila.

Recent evidence suggests that flies' sensitivity to large-field optic flow is increased by the release of octopamine during flight. This increase in gain presumably enhances visually mediated behaviors such as the active regulation of forward speed, a process that involves the comparison of a vision-based estimate of velocity with an internal set point. To determine where in the neural circuit this comparison is made, we selectively silenced the octopamine neurons in the fruit fly Drosophila, and examined the effect on vision-based velocity regulation in free-flying flies.

Octopamine neurons mediate flight-induced modulation of visual processing in Drosophila.

Background: Activity-dependent modulation of sensory systems has been documented in many organisms and is likely to be essential for appropriate processing of information during different behavioral states. However, the mechanisms underlying these phenomena remain poorly characterized.

Results: We investigated the role of octopamine neurons in the flight-dependent modulation observed in visual interneurons in Drosophila.