The Experts below are selected from a list of 32196 Experts worldwide ranked by ideXlab platform
Michael H Dickinson - One of the best experts on this subject based on the ideXlab platform.
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death valley drosophila and the devonian toolkit
Annual Review of Entomology, 2014Co-Authors: Michael H DickinsonAbstract:Most experiments on the Flight Behavior of Drosophila melanogaster have been performed within confined laboratory chambers, yet the natural history of these animals involves dispersal that takes place on a much larger spatial scale. Thirty years ago, a group of population geneticists performed a series of mark-and-recapture experiments on Drosophila flies, which demonstrated that even cosmopolitan species are capable of covering 10 km of open desert, probably in just a few hours and without the possibility of feeding along the way. In this review I revisit these fascinating and informative experiments and attempt to explain how—from takeoff to landing—the flies might have made these journeys based on our current knowledge of Flight Behavior. This exercise provides insight into how animals generate long Behavioral sequences using sensory-motor modules that may have an ancient evolutionary origin.
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visual edge orientation shapes free Flight Behavior in drosophila
Fly, 2007Co-Authors: Mark A Frye, Michael H DickinsonAbstract:Insects rely on visual cues to estimate and control their distance to approaching objects and their Flight speed. Here we show that in free-Flight, the motion cues generated by high-contrast vertical edges are crucial for these estimates. Within a visual environment dominated by high-contrast horizontal edges, flies fly unusually fast and barely avoid colliding with the walls of the enclosure. The disruption of Flight Behavior by horizontal edges provides insight into the structure of visually-mediated control algorithms.
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closing the loop between neurobiology and Flight Behavior in drosophila
Current Opinion in Neurobiology, 2004Co-Authors: Mark A Frye, Michael H DickinsonAbstract:Fruit flies alter Flight direction by generating rapid stereotyped turns called saccades. Using a combination of tethered and free-Flight methods, both the aerodynamic mechanisms and the sensory triggers for saccades have been investigated. The results indicate that saccades are elicited by visual expansion, and are brought about by remarkably subtle changes in wing motion. Mechanosensory feedback from the fly's 'gyroscope' complements visual cues to terminate saccades, as well as to stabilize forward Flight. Olfactory stimuli elicit tonic increases in wingbeat amplitude and frequency but do not alter the time course or magnitude of visual reflexes.
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odor localization requires visual feedback during free Flight in drosophila melanogaster
The Journal of Experimental Biology, 2003Co-Authors: Mark A Frye, Michael Tarsitano, Michael H DickinsonAbstract:Adult fruit flies follow attractive odors associated with food and oviposition sites through widely varied visual landscapes. To examine the interaction between olfactory and visual cues during search Behavior, we recorded three-dimensional Flight trajectories as individuals explored controlled sensory landscapes. When presented with the source of an attractive odor invisibly embedded in the floor of a 1 m arena, flies spend most of their time hovering back and forth over the source when flying within a randomly textured visual background but fail to localize the source when searching within a uniform white surround. To test whether flies are associating unique features of the visual background with the strength of odor cues, we flew them within arenas containing evenly spaced vertical stripes. Flies readily localized the odor when flying within visual landscapes lacking azimuthal landmarks provided that vertical edges were present. Flies failed to localize odor when flying within a background pattern consisting of horizontal stripes. These results suggest that, whereas flies do not require spatially unique visual patterns to localize an odor source, they do require visual feedback generated by vertical edges. Quantitative shifts in several components of Flight Behavior accompanied successful odor localization. Flies decrease Flight altitude, turn more often and approach visually textured walls of the arena near an odor source. A simple model based on the statistics of Flight Behavior supports the hypothesis that a subtle influence on these Behaviors is sufficient to lead a fly to its food.
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the influence of visual landscape on the free Flight Behavior of the fruit fly drosophila melanogaster
The Journal of Experimental Biology, 2002Co-Authors: Lance F Tammero, Michael H DickinsonAbstract:To study the visual cues that control steering Behavior in the fruit fly Drosophila melanogaster, we reconstructed three-dimensional trajectories from images taken by stereo infrared video cameras during free Flight within structured visual landscapes. Flies move through their environment using a series of straight Flight segments separated by rapid turns, termed saccades, during which the fly alters course by approximately 90 degrees in less than 100 ms. Altering the amount of background visual contrast caused significant changes in the fly's translational velocity and saccade frequency. Between saccades, asymmetries in the estimates of optic flow induce gradual turns away from the side experiencing a greater motion stimulus, a Behavior opposite to that predicted by a Flight control model based upon optomotor equilibrium. To determine which features of visual motion trigger saccades, we reconstructed the visual environment from the fly's perspective for each position in the Flight trajectory. From these reconstructions, we modeled the fly's estimation of optic flow on the basis of a two-dimensional array of Hassenstein-Reichardt elementary motion detectors and, through spatial summation, the large-field motion stimuli experienced by the fly during the course of its Flight. Event-triggered averages of the large-field motion preceding each saccade suggest that image expansion is the signal that triggers each saccade. The asymmetry in output of the local motion detector array prior to each saccade influences the direction (left versus right) but not the magnitude of the rapid turn. Once initiated, visual feedback does not appear to influence saccade kinematics further. The total expansion experienced before a saccade was similar for Flight within both uniform and visually textured backgrounds. In summary, our data suggest that complex Behavioral patterns seen during free Flight emerge from interactions between the Flight control system and the visual environment.
Cynthia F Moss - One of the best experts on this subject based on the ideXlab platform.
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Echo interval and not echo intensity drives bat Flight Behavior in structured corridors.
The Journal of experimental biology, 2018Co-Authors: Michaela Warnecke, Silvio Macías, Benjamin Falk, Cynthia F MossAbstract:To navigate in the natural environment, animals must adapt their locomotion in response to environmental stimuli. The echolocating bat relies on auditory processing of echo returns to represent its surroundings. Recent studies have shown that echo flow patterns influence bat navigation, but the acoustic basis for Flight path selection remains unknown. To investigate this problem, we released bats in a Flight corridor with walls constructed of adjacent individual wooden poles, which returned cascades of echoes to the flying bat. We manipulated the spacing and echo strength of the poles comprising each corridor side, and predicted that bats would adapt their Flight paths to deviate toward the corridor side returning weaker echo cascades. Our results show that the bat's trajectory through the corridor was not affected by the intensity of echo cascades. Instead, bats deviated toward the corridor wall with more sparsely spaced, highly reflective poles, suggesting that pole spacing, rather than echo intensity, influenced bat Flight path selection. This result motivated investigation of the neural processing of echo cascades. We measured local evoked auditory responses in the bat inferior colliculus to echo playback recordings from corridor walls constructed of sparsely and densely spaced poles. We predicted that evoked neural responses would be discretely modulated by temporally distinct echoes recorded from the sparsely spaced pole corridor wall, but not by echoes from the more densely spaced corridor wall. The data confirm this prediction and suggest that the bat's temporal resolution of echo cascades may drive its Flight Behavior in the corridor.
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echolocation and Flight Behavior of the bat hipposideros armiger terasensis in a structured corridor
Journal of the Acoustical Society of America, 2018Co-Authors: Michaela Warnecke, Benjamin Falk, Cynthia F MossAbstract:In this study, the echolocation and Flight Behaviors of the Taiwanese leaf-nosed bat (Hipposideros armiger terasensis), which uses constant-frequency (CF) biosonar signals combined with a frequency-modulated (FM) sweep, are compared with those of the big brown bat (Eptesicus fuscus), which uses FM signals alone. The CF-FM bat flew through a corridor bounded by vertical poles on either side, and the inter-pole spacing of the walls was manipulated to create different echo flow conditions. The bat's Flight trajectories and echolocation Behaviors across corridor conditions were analyzed. Like the big brown bat, the Taiwanese leaf-nosed bat centered its Flight trajectory within the corridor when the pole spacing was the same on the two walls. However, the two species showed different Flight Behaviors when the pole spacing differed on the two walls. While the big brown bat deviated from the corridor center towards the wall with sparse pole spacing, the Taiwanese leaf-nosed bat did not. Further, in comparison to E. fuscus, H. a. terasensis utilized different echolocation patterns showing a prevalence of grouping sounds into clusters of three. These findings indicate that the two species' distinct sonar signal designs contribute to their differences in Flight trajectories in a structured corridor.
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bats coordinate sonar and Flight Behavior as they forage in open and cluttered environments
The Journal of Experimental Biology, 2014Co-Authors: Benjamin Falk, Lasse Hjort Jakobsen, Annemarie Surlykke, Cynthia F MossAbstract:Echolocating bats use active sensing as they emit sounds and listen to the returning echoes to probe their environment for navigation, obstacle avoidance and pursuit of prey. The sensing Behavior of bats includes the planning of 3D spatial trajectory paths, which are guided by echo information. In this study, we examined the relationship between active sonar sampling and Flight motor output as bats changed environments from open space to an artificial forest in a laboratory Flight room. Using high-speed video and audio recordings, we reconstructed and analyzed 3D Flight trajectories, sonar beam aim and acoustic sonar emission patterns as the bats captured prey. We found that big brown bats adjusted their sonar call structure, temporal patterning and Flight speed in response to environmental change. The sonar beam aim of the bats predicted the Flight turn rate in both the open room and the forest. However, the relationship between sonar beam aim and turn rate changed in the forest during the final stage of prey pursuit, during which the bat made shallower turns. We found Flight stereotypy developed over multiple days in the forest, but did not find evidence for a reduction in active sonar sampling with experience. The temporal patterning of sonar sound groups was related to path planning around obstacles in the forest. Together, these results contribute to our understanding of how bats coordinate echolocation and Flight Behavior to represent and navigate their environment.
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effects of competitive prey capture on Flight Behavior and sonar beam pattern in paired big brown bats eptesicus fuscus
The Journal of Experimental Biology, 2010Co-Authors: Chen Chiu, Puduru Viswanadha Reddy, Wei Xian, P S Krishnaprasad, Cynthia F MossAbstract:Foraging and Flight Behavior of echolocating bats were quantitatively analyzed in this study. Paired big brown bats, Eptesicus fuscus, competed for a single food item in a large laboratory Flight room. Their sonar beam patterns and Flight paths were recorded by a microphone array and two high-speed cameras, respectively. Bats often remained in nearly classical pursuit (CP) states when one bat is following another bat. A follower can detect and anticipate the movement of the leader, while the leader has the advantage of gaining access to the prey first. Bats in the trailing position throughout the trial were more successful in accessing the prey. In this study, bats also used their sonar beam to monitor the conspecific's movement and to track the prey. Each bat tended to use its sonar beam to track the prey when it was closer to the worm than to another bat. The trailing bat often directed its sonar beam toward the leading bat in following Flight. When two bats flew towards each other, they tended to direct their sonar beam axes away from each other, presumably to avoid signal jamming. This study provides a new perspective on how echolocating bats use their biosonar system to coordinate their Flight with conspecifics in a group and how they compete for the same food source with conspecifics.
Eric J. Warrant - One of the best experts on this subject based on the ideXlab platform.
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The Earth's Magnetic Field and Visual Landmarks Steer Migratory Flight Behavior in the Nocturnal Australian Bogong Moth.
Current Biology, 2018Co-Authors: David Dreyer, Barrie J. Frost, Henrik Mouritsen, Anja Günther, Ken Green, Mary E. A. Whitehouse, Sönke Johnsen, Stanley Heinze, Eric J. WarrantAbstract:Like many birds [1], numerous species of nocturnal moths undertake spectacular long-distance migrations at night [2]. Each spring, billions of Bogong moths (Agrotis infusa) escape hot conditions in different regions of southeast Australia by making a highly directed migration of over 1,000 km to a limited number of cool caves in the Australian Alps, historically used for aestivating over the summer [3, 4]. How moths determine the direction of inherited migratory trajectories at night and locate their destination (i.e., navigate) is currently unknown [5–7]. Here we show that Bogong moths can sense the Earth's magnetic field and use it in conjunction with visual landmarks to steer migratory Flight Behavior. By tethering migrating moths in an outdoor Flight simulator [8], we found that their Flight direction turned predictably when dominant visual landmarks and a natural Earth-strength magnetic field were turned together, but that the moths became disoriented within a few minutes when these cues were set in conflict. We thus conclude that Bogong moths, like nocturnally migrating birds [9], can use a magnetic sense. Our results represent the first reliable demonstration of the use of the Earth's magnetic field to steer Flight Behavior in a nocturnal migratory insect. The nocturnal Bogong moth performs a highly directed long-distance migration to and from alpine caves in the Australian Alps. Dreyer et al. show that this moth senses the Earth's magnetic field and uses it together with visual landmarks to steer migratory Flight Behavior. The geomagnetic field might thus be used as a compass during migration. (Less)
Mark A Frye - One of the best experts on this subject based on the ideXlab platform.
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visual edge orientation shapes free Flight Behavior in drosophila
Fly, 2007Co-Authors: Mark A Frye, Michael H DickinsonAbstract:Insects rely on visual cues to estimate and control their distance to approaching objects and their Flight speed. Here we show that in free-Flight, the motion cues generated by high-contrast vertical edges are crucial for these estimates. Within a visual environment dominated by high-contrast horizontal edges, flies fly unusually fast and barely avoid colliding with the walls of the enclosure. The disruption of Flight Behavior by horizontal edges provides insight into the structure of visually-mediated control algorithms.
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closing the loop between neurobiology and Flight Behavior in drosophila
Current Opinion in Neurobiology, 2004Co-Authors: Mark A Frye, Michael H DickinsonAbstract:Fruit flies alter Flight direction by generating rapid stereotyped turns called saccades. Using a combination of tethered and free-Flight methods, both the aerodynamic mechanisms and the sensory triggers for saccades have been investigated. The results indicate that saccades are elicited by visual expansion, and are brought about by remarkably subtle changes in wing motion. Mechanosensory feedback from the fly's 'gyroscope' complements visual cues to terminate saccades, as well as to stabilize forward Flight. Olfactory stimuli elicit tonic increases in wingbeat amplitude and frequency but do not alter the time course or magnitude of visual reflexes.
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odor localization requires visual feedback during free Flight in drosophila melanogaster
The Journal of Experimental Biology, 2003Co-Authors: Mark A Frye, Michael Tarsitano, Michael H DickinsonAbstract:Adult fruit flies follow attractive odors associated with food and oviposition sites through widely varied visual landscapes. To examine the interaction between olfactory and visual cues during search Behavior, we recorded three-dimensional Flight trajectories as individuals explored controlled sensory landscapes. When presented with the source of an attractive odor invisibly embedded in the floor of a 1 m arena, flies spend most of their time hovering back and forth over the source when flying within a randomly textured visual background but fail to localize the source when searching within a uniform white surround. To test whether flies are associating unique features of the visual background with the strength of odor cues, we flew them within arenas containing evenly spaced vertical stripes. Flies readily localized the odor when flying within visual landscapes lacking azimuthal landmarks provided that vertical edges were present. Flies failed to localize odor when flying within a background pattern consisting of horizontal stripes. These results suggest that, whereas flies do not require spatially unique visual patterns to localize an odor source, they do require visual feedback generated by vertical edges. Quantitative shifts in several components of Flight Behavior accompanied successful odor localization. Flies decrease Flight altitude, turn more often and approach visually textured walls of the arena near an odor source. A simple model based on the statistics of Flight Behavior supports the hypothesis that a subtle influence on these Behaviors is sufficient to lead a fly to its food.
Ru Song - One of the best experts on this subject based on the ideXlab platform.
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a vta gabaergic neural circuit mediates visually evoked innate defensive responses
Neuron, 2019Co-Authors: Zheng Zhou, Xuemei Liu, Shanping Chen, Zhijian Zhang, Yuanming Liu, Quentin Montardy, Yongqiang Tang, Pengfei Wei, Nan Liu, Ru SongAbstract:Innate defensive responses are essential for animal survival and are conserved across species. The ventral tegmental area (VTA) plays important roles in learned appetitive and aversive Behaviors, but whether it plays a role in mediating or modulating innate defensive responses is currently unknown. We report that VTAGABA+ neurons respond to a looming stimulus. Inhibition of VTAGABA+ neurons reduced looming-evoked defensive Flight Behavior, and photoactivation of these neurons resulted in defense-like Flight Behavior. Using viral tracing and electrophysiological recordings, we show that VTAGABA+ neurons receive direct excitatory inputs from the superior colliculus (SC). Furthermore, we show that glutamatergic SC-VTA projections synapse onto VTAGABA+ neurons that project to the central nucleus of the amygdala (CeA) and that the CeA is involved in mediating the defensive Behavior. Our findings demonstrate that aerial threat-related visual information is relayed to VTAGABA+ neurons mediating innate Behavioral responses, suggesting a more general role of the VTA.