Data and software for: Temporal novelty detection and multiple timescale integration drive Drosophila orientation dynamics in temporally diverse olfactory environments

To survive, insects must effectively navigate odors plumes to their
source. In natural plumes, turbulent winds break up smooth odor regions
into disconnected patches, so navigators encounter brief bursts of odor
interrupted by bouts of clean air. The timing of these encounters plays a
critical role in navigation, determining the direction, rate, and
magnitude of insects’ orientation and speed dynamics. Disambiguating the
specific role of odor timing from other cues, such as spatial structure,
is challenging due to natural correlations between plumes’ temporal and
spatial features. Here, we use optogenetics to isolate temporal features
of odor signals, examining how the frequency and duration of odor
encounters shape the navigational decisions of
freely-walking Drosophila. We find that fly angular velocity
depends on signal frequency and intermittency – fraction of time signal
can be detected – but not directly on durations. Rather than switching
strategies when signal statistics change, flies smoothly transition
between signal regimes, by combining an odor offset response with a
frequency-dependent novelty-like response. In the latter, flies are more
likely to turn in response to each odor hit only when the hits are sparse.
Finally, the upwind bias of individual turns relies on a filtering scheme
with two distinct timescales, allowing rapid and sustained responses in a
variety of signal statistics. A quantitative model incorporating these
ingredients recapitulates fly orientation dynamics across a wide range of
environments and shows that temporal novelty detection, when combined with
odor motion detection, enhances odor plume navigation.