Statistical structure of locomotion and its modulation by odors

Tao, Liangyu; Ozarkar, Siddhi; Beck, Jeffrey M.; Bhandawat, Vikas

doi:10.7554/elife.41235

Cited by 39 publications

(38 citation statements)

References 54 publications

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“…Since each state lasts 1 second on an average, it implies that the fly makes one decision (in selecting speed and curvature) every second on average. This feature of the model is consistent with the Hierarchical Hidden Markov Model (HHMM) employed in a previous study [37]. HHMM showed that the fly moved at similar speed and curvature over long durations.…”

Section: Discussionsupporting

confidence: 87%

“…2 (see Methods for details) by sampling from speed, curvature and duration distributions for each state (S3 Fig and S4 Fig). Consistent with previous work [27,37], the behavior of the fly is different inside the light-zone and outside it, therefore three different distributions were used to model the fly's behavior-before the presence of light, during-inside and during-outside. The duration that each transition lasted was also selected from the empirical distribution (S3 Fig and S4 Fig).…”

Section: Plos Computational Biologymentioning

confidence: 90%

“…Because flies tend to move over relatively long periods with similar speed and curvature (37), it is likely that each transition to one of the three states can be defined by a few parameters: Modeling stops is straightforward; stops can be modeled by two parameters-stop duration, and the change in a fly's orientation during the stop. To investigate whether curved walk and sharp turns can be modeled using a few parameters we compared empirical track segments to synthetic ones that represented abstractions of the empirical tracks.…”

Section: A Fly Changes Its Orientation Using Three Mechanismsmentioning

confidence: 99%

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Mechanisms underlying attraction to odors in walking Drosophila

2020

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Mechanisms that control movements range from navigational mechanisms, in which the animal employs directional cues to reach a specific destination, to search movements during which there are little or no environmental cues. Even though most real-world movements result from an interplay between these mechanisms, an experimental system and theoretical framework for the study of interplay of these mechanisms is not available. Here, we rectify this deficit. We create a new method to stimulate the olfactory system in Drosophila or fruit flies. As flies explore a circular arena, their olfactory receptor neuron (ORNs) are optogenetically activated within a central region making this region attractive to the flies without emitting any clear directional signals outside this central region. In the absence of ORN activation, the fly's locomotion can be described by a random walk model where a fly's movement is described by its speed and turn-rate (or kinematics). Upon optogenetic stimulation, the fly's behavior changes dramatically in two respects. First, there are large kinematic changes. Second, there are more turns at the border between light-zone and no-light-zone and these turns have an inward bias. Surprisingly, there is no increase in turn-rate, rather a large decrease in speed that makes it appear that the flies are turning at the border. Similarly, the inward bias of the turns is a result of the increase in turn angle. These two mechanisms entirely account for the change in a fly's locomotion. No complex mechanisms such as path-integration or a careful evaluation of gradients are necessary.

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Section: Discussionsupporting

confidence: 87%

Section: Plos Computational Biologymentioning

confidence: 90%

Section: A Fly Changes Its Orientation Using Three Mechanismsmentioning

confidence: 99%

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Mechanisms underlying attraction to odors in walking Drosophila

2020

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“…Although searches triggered by sugar, water, and odor sensation appear broadly similar in our experiments (Figures 1C, 2H and 2J), it is likely that their underlying behavioral structure differs [26,44]. For example, we found that whereas activation of Gr43a-, Gr5a-Ir76b-, ppk28-, or NPF-GAL4 results in a drop in locomotor rate or complete stopping, activation of ACV-odor-sensing Or42b-GAL4 neurons only elicits a brief startle response similar to controls ( Figures S4B and S4C).…”

Section: The Extent Of Local Search Is Modulated By Starvation Statementioning

confidence: 81%

Diverse Food-Sensing Neurons Trigger Idiothetic Local Search in Drosophila

2019

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Resources are often sparsely clustered in nature. Thus, foraging animals may benefit from remembering the location of a newly discovered food patch while continuing to explore nearby [1,2]. For example, after encountering a drop of yeast or sugar, hungry flies often perform a local search consisting of frequent departures and returns to the food site [3,4]. Fruit flies, Drosophila melanogaster, can perform this food-centered search behavior in the absence of external stimuli or landmarks, instead relying solely on internal (idiothetic) cues to keep track of their location [5]. This path integration behavior may represent a deeply conserved navigational capacity in insects [6,7], but the neural pathways underlying food-triggered searches remain unknown. Here, we used optogenetic activation to screen candidate cell classes and found that local searches can be initiated by diverse sensory neurons including sugar-sensors, water-sensors, olfactory-receptor neurons, as well as hunger-signaling neurons of the central nervous system. Optogenetically-induced searches resemble those triggered by actual food and are modulated by starvation state. Furthermore, search trajectories exhibit key features of path integration: searches remain tightly centered around the fictive-food site, even during long periods without reinforcement, and flies re-center their searches when they encounter a new fictive-food site. Flies can even perform elaborate local searches within a constrained maze. Together, these results suggest that flies enact local searches in response to a wide variety of food-associated cues, and that these sensory pathways may converge upon a common neural system for path integration. Optogenetically induced local searches in Drosophila can now serve as a tractable system for the study of spatial memory and navigation in insects.

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“…Each video frame was assigned a behavioral label, which was used to calculate the probabilities of using each behavioral state, as well as the probabilities of transitioning between states. The model output was also used to compute forward and side velocities as previously described 41 statistic. To assess individual differences between behavioral states, we estimated the variance of the data through bootstrapping.…”

Section: Continuous Behavioral Classificationmentioning

confidence: 99%

A diencephalic pathway for movement initiation and rescue of Parkinsonian symptoms

Watson

Petter

et al. 2018

Preprint

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The parafascicular nucleus (Pf) of the thalamus projects to the subthalamic nucleus (STN), a major target for deep brain stimulation (DBS) in Parkinson's disease (PD), but the function of this projection remains unknown. Here, we used optogenetics, 3D motion capture, in vivo electrophysiology and 1-photon calcium imaging, unsupervised behavioral classification, and viral-based neuroanatomical tracing to examine the contribution of Pf efferents to movement generation in mice. We discovered that Pf neurons are highly correlated with movement velocity and excitation of Pf neurons generates turning and orienting movements. Movement initiation was not due to Pf projections to the striatum, but rather its projections to the STN. Optogenetic excitation of the Pf-STN pathway restores movement in a common mouse model of PD with complete akinesia. Collectively, our results reveal a thalamo-subthalamic pathway regulating movement initiation, and demonstrate a circuit mechanism that could potentially explain the clinical efficacy of DBS for relief of PD motor symptoms.

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Statistical structure of locomotion and its modulation by odors

Cited by 39 publications

References 54 publications

Mechanisms underlying attraction to odors in walking Drosophila

Mechanisms underlying attraction to odors in walking Drosophila

Diverse Food-Sensing Neurons Trigger Idiothetic Local Search in Drosophila

A diencephalic pathway for movement initiation and rescue of Parkinsonian symptoms

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