The Experts below are selected from a list of 327 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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the aerodynamics and control of Free Flight manoeuvres in drosophila
Philosophical Transactions of the Royal Society B, 2016Co-Authors: Michael H Dickinson, Florian T MuijresAbstract:A firm understanding of how fruit flies hover has emerged over the past two decades, and recent work has focused on the aerodynamic, biomechanical and neurobiological mechanisms that enable them to manoeuvre and resist perturbations. In this review, we describe how flies manipulate wing movement to control their body motion during active manoeuvres, and how these actions are regulated by sensory feedback. We also discuss how the application of control theory is providing new insight into the logic and structure of the circuitry that underlies Flight stability.
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visual stimulation of saccades in magnetically tethered drosophila
The Journal of Experimental Biology, 2006Co-Authors: John A Bender, Michael H DickinsonAbstract:Flying fruit flies, Drosophila melanogaster, perform `body saccades', in which they change heading by about 90° in roughly 70 ms. In Free Flight, visual expansion can evoke saccades, and saccade-like turns are triggered by similar stimuli in tethered flies. However, because the fictive turns in rigidly tethered flies follow a much longer time course, the extent to which these two behaviors share a common neural basis is unknown. A key difference between tethered and Free Flight conditions is the presence of additional sensory cues in the latter, which might serve to modify the time course of the saccade motor program. To study the role of sensory feedback in saccades, we have developed a new preparation in which a fly is tethered to a fine steel pin that is aligned within a vertically oriented magnetic field, allowing it to rotate Freely around its yaw axis. In this experimental paradigm, flies perform rapid turns averaging 35° in 80 ms, similar to the kinematics of Free Flight saccades. Our results indicate that tethered and Free Flight saccades share a common neural basis, but that the lack of appropriate feedback signals distorts the behavior performed by rigidly fixed flies. Using our new paradigm, we also investigated the features of visual stimuli that elicit saccades. Our data suggest that saccades are triggered when expanding objects reach a critical threshold size, but that their timing depends little on the precise time course of expansion. These results are consistent with expansion detection circuits studied in other insects, but do not exclude other models based on the integration of local movement detectors.
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Free Flight responses of drosophila melanogaster to attractive odors
The Journal of Experimental Biology, 2006Co-Authors: Seth A Budick, Michael H DickinsonAbstract:Many motile organisms localize the source of attractive odorants by following plumes upwind. In the case of D. melanogaster, little is known of how individuals alter their Flight trajectories after encountering and losing a plume of an attractive odorant. We have characterized the three-dimensional Flight behavior of D. melanogaster in a wind tunnel under a variety of odor conditions. In the absence of olfactory cues, hungry flies initiate Flight and display anemotactic orientation. Following contact with a narrow ribbon plume of an attractive odor, flies reduce their crosswind velocity while flying faster upwind, resulting in a surge directed toward the odor source. Following loss of odor contact due to plume truncation, flies frequently initiate a stereotyped crosswind casting response, a behavior rarely observed in a continuous odor plume. Similarly, within a homogeneous odor cloud, flies move fast while maintaining an upwind heading. These results indicate both similarities and differences between the behavior of D. melanogaster and the responses of male moths to pheromone plumes, suggesting possible differences in underlying neural mechanisms.
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the aerodynamics of Free Flight maneuvers in drosophila
Science, 2003Co-Authors: Steven N Fry, Rosalyn W Sayaman, Michael H DickinsonAbstract:Using three-dimensional infrared high-speed video, we captured the wing and body kinematics of Free-flying fruit flies as they performed rapid Flight maneuvers. We then “replayed” the wing kinematics on a dynamically scaled robotic model to measure the aerodynamic forces produced by the wings. The results show that a fly generates rapid turns with surprisingly subtle modifications in wing motion, which nonetheless generate sufficient torque for the fly to rotate its body through each turn. The magnitude and time course of the torque and body motion during rapid turns indicate that inertia, not friction, dominates the Flight dynamics of insects.
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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.
David D. Yager - One of the best experts on this subject based on the ideXlab platform.
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Free Flight encounters between praying mantids parasphendale agrionina and bats eptesicus fuscus
The Journal of Experimental Biology, 2008Co-Authors: Jeffrey D Triblehorn, Kaushik Ghose, Kari Bohn, Cynthia F Moss, David D. YagerAbstract:Through staged Free-Flight encounters between echolocating bats and praying mantids, we examined the effectiveness of two potential predator-evasion behaviors mediated by different sensory modalities: (1) power dive responses triggered by bat echolocation detected by the mantis ultrasound-sensitive auditory system, and (2) ;last-ditch' maneuvers triggered by bat-generated wind detected by the mantis cercal system. Hearing mantids escaped more often than deafened mantids (76% vs 34%, respectively; hearing conveyed 42% advantage). Hearing mantis escape rates decreased when bat attack sequences contained very rapid increases in pulse repetition rates (escape rates 16 p.p.s. 10 ms(-1); escape rates >60% for transition slopes 16 p.p.s. 10 ms(-1)) could circumvent mantis/insect auditory defenses. However, echolocation attack sequences containing such transitions occurred in only 15% of the trials. Since mantis ultrasound-mediated responses are not 100% effective, cercal-mediated evasive behaviors triggered by bat-generated wind could be beneficial as a backup/secondary system. Although deafened mantids with functioning cerci did not escape more often than deafened mantids with deactivated cerci (35% vs 32%, respectively), bats dropped mantids with functioning cerci twice as frequently as mantids with deactivated cerci. This latter result was not statistically reliable due to small sample sizes, since this study was not designed to fully evaluate this result. It is an interesting observation that warrants further investigation, however, especially since these dropped mantids always survived the encounter.
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Free Flight encounters between praying mantids parasphendale agrionina and bats eptesicus fuscus
The Journal of Experimental Biology, 2008Co-Authors: Jeffrey D Triblehorn, Kaushik Ghose, Kari Bohn, Cynthia F Moss, David D. YagerAbstract:SUMMARY Through staged Free-Flight encounters between echolocating bats and praying mantids, we examined the effectiveness of two potential predator-evasion behaviors mediated by different sensory modalities: (1) power dive responses triggered by bat echolocation detected by the mantis ultrasound-sensitive auditory system, and (2) `last-ditch9 maneuvers triggered by bat-generated wind detected by the mantis cercal system. Hearing mantids escaped more often than deafened mantids (76% vs 34%, respectively; hearing conveyed 42% advantage). Hearing mantis escape rates decreased when bat attack sequences contained very rapid increases in pulse repetition rates (escape rates <40% for transition slopes >16 p.p.s. 10 ms –1 ; escape rates> 60% for transition slopes –1 ). This suggests that echolocation attack sequences containing very rapid transitions (>16 p.p.s. 10 ms –1 ) could circumvent mantis/insect auditory defenses. However, echolocation attack sequences containing such transitions occurred in only 15% of the trials. Since mantis ultrasound-mediated responses are not 100% effective, cercal-mediated evasive behaviors triggered by bat-generated wind could be beneficial as a backup/secondary system. Although deafened mantids with functioning cerci did not escape more often than deafened mantids with deactivated cerci (35% vs 32%, respectively), bats dropped mantids with functioning cerci twice as frequently as mantids with deactivated cerci. This latter result was not statistically reliable due to small sample sizes, since this study was not designed to fully evaluate this result. It is an interesting observation that warrants further investigation, however, especially since these dropped mantids always survived the encounter.
Michel M Maharbiz - One of the best experts on this subject based on the ideXlab platform.
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remote radio control of insect Flight
Frontiers in Integrative Neuroscience, 2009Co-Authors: Hirotaka Sato, Christopher W Berry, Yoav Peeri, Emen Baghoomian, Brendan E Casey, G Lavella, John M Vandenbrooks, Jon F Harrison, Michel M MaharbizAbstract:We demonstrated the remote control of insects in Free Flight via an implantable radio-equipped miniature neural stimulating system. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and Free-Flight trajectories elicited by our neural control systems in remotely-controlled beetles. We believe this type of technology will open the door to in-Flight perturbation and recording of insect Flight responses.
Jacco Hoekstra - One of the best experts on this subject based on the ideXlab platform.
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designing for safety the Free Flight air traffic management concept
Reliability Engineering & System Safety, 2002Co-Authors: Jacco HoekstraAbstract:Abstract This paper describes the conceptual design and validation of an air traffic management (ATM) concept and the role the safety and human factors played in this design and validation process. The Free Flight (FF) concept is characterised by being a direct route concept where the pilots, instead of the air traffic controller, are responsible for the separation assurance. Moving this task to the cockpit has consequences for the man machine interface in the cockpit, which needs to be modified to accommodate this new task (micro level design). On top of that, a set of rules and procedures are required to ensure an efficient and safe traffic flow (macro level design). Both the micro and macro aspect of this design are intertwined and require an accurate tuning to arrive at an overall acceptable solution. Both micro-level (Flight simulator) experiments and macro-level (traffic simulations) experiments have been conducted to investigate the feasibility of this concept after optimising the initial conceptual design.
Jeffrey D Triblehorn - One of the best experts on this subject based on the ideXlab platform.
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Free Flight encounters between praying mantids parasphendale agrionina and bats eptesicus fuscus
The Journal of Experimental Biology, 2008Co-Authors: Jeffrey D Triblehorn, Kaushik Ghose, Kari Bohn, Cynthia F Moss, David D. YagerAbstract:Through staged Free-Flight encounters between echolocating bats and praying mantids, we examined the effectiveness of two potential predator-evasion behaviors mediated by different sensory modalities: (1) power dive responses triggered by bat echolocation detected by the mantis ultrasound-sensitive auditory system, and (2) ;last-ditch' maneuvers triggered by bat-generated wind detected by the mantis cercal system. Hearing mantids escaped more often than deafened mantids (76% vs 34%, respectively; hearing conveyed 42% advantage). Hearing mantis escape rates decreased when bat attack sequences contained very rapid increases in pulse repetition rates (escape rates 16 p.p.s. 10 ms(-1); escape rates >60% for transition slopes 16 p.p.s. 10 ms(-1)) could circumvent mantis/insect auditory defenses. However, echolocation attack sequences containing such transitions occurred in only 15% of the trials. Since mantis ultrasound-mediated responses are not 100% effective, cercal-mediated evasive behaviors triggered by bat-generated wind could be beneficial as a backup/secondary system. Although deafened mantids with functioning cerci did not escape more often than deafened mantids with deactivated cerci (35% vs 32%, respectively), bats dropped mantids with functioning cerci twice as frequently as mantids with deactivated cerci. This latter result was not statistically reliable due to small sample sizes, since this study was not designed to fully evaluate this result. It is an interesting observation that warrants further investigation, however, especially since these dropped mantids always survived the encounter.
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Free Flight encounters between praying mantids parasphendale agrionina and bats eptesicus fuscus
The Journal of Experimental Biology, 2008Co-Authors: Jeffrey D Triblehorn, Kaushik Ghose, Kari Bohn, Cynthia F Moss, David D. YagerAbstract:SUMMARY Through staged Free-Flight encounters between echolocating bats and praying mantids, we examined the effectiveness of two potential predator-evasion behaviors mediated by different sensory modalities: (1) power dive responses triggered by bat echolocation detected by the mantis ultrasound-sensitive auditory system, and (2) `last-ditch9 maneuvers triggered by bat-generated wind detected by the mantis cercal system. Hearing mantids escaped more often than deafened mantids (76% vs 34%, respectively; hearing conveyed 42% advantage). Hearing mantis escape rates decreased when bat attack sequences contained very rapid increases in pulse repetition rates (escape rates <40% for transition slopes >16 p.p.s. 10 ms –1 ; escape rates> 60% for transition slopes –1 ). This suggests that echolocation attack sequences containing very rapid transitions (>16 p.p.s. 10 ms –1 ) could circumvent mantis/insect auditory defenses. However, echolocation attack sequences containing such transitions occurred in only 15% of the trials. Since mantis ultrasound-mediated responses are not 100% effective, cercal-mediated evasive behaviors triggered by bat-generated wind could be beneficial as a backup/secondary system. Although deafened mantids with functioning cerci did not escape more often than deafened mantids with deactivated cerci (35% vs 32%, respectively), bats dropped mantids with functioning cerci twice as frequently as mantids with deactivated cerci. This latter result was not statistically reliable due to small sample sizes, since this study was not designed to fully evaluate this result. It is an interesting observation that warrants further investigation, however, especially since these dropped mantids always survived the encounter.
