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43 Publications

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    07/06/19 | Cellular level analysis of the locomotor neural circuits in Drosophila melanogaster.
    minegishi r, Feng K, Dickson B
    Biomimetic and Biohybrid Systems. 2019 Jul 6:334-7
    03/12/19 | Split-QF system for fine-tuned transgene expression in Drosophila.
    Riabinina O, Vernon SW, Dickson BJ, Baines RA
    Genetics. 2019 Mar 12;212(1):53-63. doi: 10.1534/genetics.119.302034

    The Q-system is a binary expression system that works well across species. Here we report the development and demonstrate applications of a split-QF system that drives strong expression in , is repressible by QS and inducible by a small non-toxic molecule quinic acid. The split-QF system is fully compatible with existing split-GAL4 and split-LexA lines, thus greatly expanding the range of possible advanced intersectional experiments and anatomical, physiological and behavioural assays in and in other organisms.

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    03/08/19 | Neural evolution of context-dependent fly song.
    Ding Y, Lillvis JL, Cande J, Berman GJ, Arthur BJ, Long X, Xu M, Dickson BJ, Stern DL
    Current Biology : CB. 2019 Mar 08;29(7):1089-99. doi: 10.1016/j.cub.2019.02.019

    It is unclear where in the nervous system evolutionary changes tend to occur. To localize the source of neural evolution that has generated divergent behaviors, we developed a new approach to label and functionally manipulate homologous neurons across Drosophila species. We examined homologous descending neurons that drive courtship song in two species that sing divergent song types and localized relevant evolutionary changes in circuit function downstream of the intrinsic physiology of these descending neurons. This evolutionary change causes different species to produce divergent motor patterns in similar social contexts. Artificial stimulation of these descending neurons drives multiple song types, suggesting that multifunctional properties of song circuits may facilitate rapid evolution of song types.

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    01/07/19 | Threshold-based ordering of sequential actions during Drosophila courtship.
    McKellar CE, Lillvis JL, Bath DE, Fitzgerald JE, Cannon JG, Simpson JH, Dickson BJ
    Current Biology : CB. 2019 Jan 07;29(3):426-34. doi: 10.1016/j.cub.2018.12.019

    Goal-directed animal behaviors are typically composed of sequences of motor actions whose order and timing are critical for a successful outcome. Although numerous theoretical models for sequential action generation have been proposed, few have been supported by the identification of control neurons sufficient to elicit a sequence. Here, we identify a pair of descending neurons that coordinate a stereotyped sequence of engagement actions during Drosophila melanogaster male courtship behavior. These actions are initiated sequentially but persist cumulatively, a feature not explained by existing models of sequential behaviors. We find evidence consistent with a ramp-to-threshold mechanism, in which increasing neuronal activity elicits each action independently at successively higher activity thresholds.

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    07/04/18 | Visual projection neurons mediating directed courtship in Drosophila.
    Ribeiro IM, Drews M, Bahl A, Machacek C, Borst A, Dickson BJ
    Cell. 2018 Jul 04;174(3):607-21. doi: 10.1016/j.cell.2018.06.020

    Many animals rely on vision to detect, locate, and track moving objects. In Drosophila courtship, males primarily use visual cues to orient toward and follow females and to select the ipsilateral wing for courtship song. Here, we show that the LC10 visual projection neurons convey essential visual information during courtship. Males with LC10 neurons silenced are unable to orient toward or maintain proximity to the female and do not predominantly use the ipsilateral wing when singing. LC10 neurons preferentially respond to small moving objects using an antagonistic motion-based center-surround mechanism. Unilateral activation of LC10 neurons recapitulates the orienting and ipsilateral wing extension normally elicited by females, and the potency with which LC10 induces wing extension is enhanced in a state of courtship arousal controlled by male-specific P1 neurons. These data suggest that LC10 is a major pathway relaying visual input to the courtship circuits in the male brain.

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    01/11/18 | Persistent activity in a recurrent circuit underlies courtship memory in Drosophila.
    Zhao X, Lenek D, Dag U, Dickson B, Keleman K
    eLife. 2018 Jan 11;7:. doi: 10.7554/eLife.31425

    Recurrent connections are thought to be a common feature of the neural circuits that encode memories, but how memories are laid down in such circuits is not fully understood. Here we present evidence that courtship memory in Drosophila relies on the recurrent circuit between mushroom body gamma (MBg), M6 output, and aSP13 dopaminergic neurons. We demonstrate persistent neuronal activity of aSP13 neurons and show that it transiently potentiates synaptic transmission from MBγ>M6 neurons. M6 neurons in turn provide input to aSP13 neurons, prolonging potentiation of MBγ>M6 synapses over time periods that match short-term memory. These data support a model in which persistent aSP13 activity within a recurrent circuit lays the foundation for a short-term memory.

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    03/06/17 | Moonwalker descending neurons mediate visually evoked retreat in Drosophila.
    Sen R, Wu M, Branson K, Robie A, Rubin GM, Dickson BJ
    Current Biology : CB. 2017 Mar 6;27(5):766-71. doi: 10.1016/j.cub.2017.02.008

    Insects, like most animals, tend to steer away from imminent threats [1-7]. Drosophila melanogaster, for example, generally initiate an escape take-off in response to a looming visual stimulus, mimicking a potential predator [8]. The escape response to a visual threat is, however, flexible [9-12] and can alternatively consist of walking backward away from the perceived threat [11], which may be a more effective response to ambush predators such as nymphal praying mantids [7]. Flexibility in escape behavior may also add an element of unpredictability that makes it difficult for predators to anticipate or learn the prey's likely response [3-6]. Whereas the fly's escape jump has been well studied [8, 9, 13-18], the neuronal underpinnings of evasive walking remain largely unexplored. We previously reported the identification of a cluster of descending neurons-the moonwalker descending neurons (MDNs)-the activity of which is necessary and sufficient to trigger backward walking [19], as well as a population of visual projection neurons-the lobula columnar 16 (LC16) cells-that respond to looming visual stimuli and elicit backward walking and turning [11]. Given the similarity of their activation phenotypes, we hypothesized that LC16 neurons induce backward walking via MDNs and that turning while walking backward might reflect asymmetric activation of the left and right MDNs. Here, we present data from functional imaging, behavioral epistasis, and unilateral activation experiments that support these hypotheses. We conclude that LC16 and MDNs are critical components of the neural circuit that transduces threatening visual stimuli into directional locomotor output.

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    06/16/16 | Motor control of fly feeding.
    McKellar CE
    Journal of Neurogenetics. 2016 Jun 16;30(2):101-11. doi: 10.1080/01677063.2016.1177047

    Following considerable progress on the molecular and cellular basis of taste perception in fly sensory neurons, the time is now ripe to explore how taste information, integrated with hunger and satiety, undergo a sensorimotor transformation to lead to the motor actions of feeding behavior. I examine what is known of feeding circuitry in adult flies from more than 250 years of work in larger flies and from newer work in Drosophila. I review the anatomy of the proboscis, its muscles and their functions (where known), its motor neurons, interneurons known to receive taste inputs, interneurons that diverge from taste circuitry to provide information to other circuits, interneurons from other circuits that converge on feeding circuits, proprioceptors that influence the motor control of feeding, and sites of integration of hunger and satiety on feeding circuits. In spite of the several neuron types now known, a connected pathway from taste inputs to feeding motor outputs has yet to be found. We are on the threshold of an era where these individual components will be assembled into circuits, revealing how nervous system architecture leads to the control of behavior.

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    06/01/16 | Editorial overview: Neurobiology of sex.
    Dulac C, Dickson BJ
    Current Opinion in Neurobiology. 2016 Jun;38:A1-3. doi: 10.1016/j.conb.2016.06.001
    01/28/16 | Visualization and quantification for interactive analysis of neural connectivity in Drosophila.
    Swoboda N, Moosburner J, Bruckner S, Yu J, Dickson BJ, Bühler K
    Computer Graphics Forum. 2016 Jan 28:. doi: 10.1111/cgf.12792

    Neurobiologists investigate the brain of the common fruit fly Drosophila melanogaster to discover neural circuits and link them to complex behaviour. Formulating new hypotheses about connectivity requires potential connectivity information between individual neurons, indicated by overlaps of arborizations of two or more neurons. As the number of higher order overlaps (i.e. overlaps of three or more arborizations) increases exponentially with the number of neurons under investigation, visualization is impeded by clutter and quantification becomes a burden. Existing solutions are restricted to visual or quantitative analysis of pairwise overlaps, as they rely on precomputed overlap data. We present a novel tool that complements existing methods for potential connectivity exploration by providing for the first time the possibility to compute and visualize higher order arborization overlaps on the fly and to interactively explore this information in both its spatial anatomical context and on a quantitative level. Qualitative evaluation by neuroscientists and non-experts demonstrated the utility and usability of the tool.

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