1,720,969 research outputs found
Optical dissection of pre- and postsynaptic plasticity in the olfactory system of Drosophila melanogaster.
No full textVisualization of connectivities between intrinsic and extrinsic mushroom body neurons in Drosophila
No full textVisualization of connectivities between intrinsic and extrinsic mushroom body neurons in Drosophila
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Optical calcium imaging in the nervous system of Drosophila melanogaster
No full textBackground: Drosophila melanogaster is one of the best-studied model organisms in biology, mainly because of the versatility of methods by which heredity and specific expression of genes can be traced and manipulated. Sophisticated genetic tools have been developed to express transgenes in selected cell types, and these techniques can be utilized to target DNA-encoded fluorescence probes to genetically defined subsets of neurons. Neuroscientists make use of this approach to monitor the activity of restricted types or subsets of neurons in the brain and the peripheral nervous system. Since membrane depolarization is typically accompanied by an increase in intracellular calcium ions, calcium-sensitive fluorescence proteins provide favorable tools to monitor the spatio-temporal activity across groups of neurons. Scope of review: Here we describe approaches to perform optical calcium imaging in Drosophila in consideration of various calcium sensors and expression systems. In addition, we outline by way of examples for which particular neuronal systems in Drosophila optical calcium imaging have been used. Finally, we exemplify briefly how optical calcium imaging in the brain of Drosophila can be carried out in practice. Major conclusions and general significance: Drosophila provides an excellent model organism to combine genetic expression systems with optical calcium imaging in order to investigate principles of sensory coding, neuronal plasticity, and processing of neuronal information underlying behavior. This article is part of a Special Issue entitled Biochemical, Biophysical and Genetic Approaches to Intracellular Calcium Signaling. (C) 2012 Elsevier B.V. All rights reserved
Brain Using SplitGFP Reconstitution
No full textThe mushroom body of the insect brain represents a neuronal circuit involved in the control of adaptive behavior, e.g., associative learning. Its function relies on the modulation of Kenyon cell activity or synaptic transmitter release by biogenic amines, e.g., octopamine, dopamine, or serotonin. Therefore, for a comprehensive understanding of the mushroom body, it is of interest not only to determine which modulatory neurons interact with Kenyon cells but also to pinpoint where exactly in the mushroom body they do so. To accomplish the latter, we made use of the GRASP technique and created transgenic Drosophila melanogaster that carry one part of a membrane-bound splitGFP in Kenyon cells, along with a cytosolic red fluorescent marker. The second part of the splitGFP is expressed in distinct neuronal populations using cell-specific Gal4 drivers. GFP is reconstituted only if these neurons interact with Kenyon cells in close proximity, which, in combination with two-photon microscopy, provides a very high spatial resolution. We characterize spatially and microstructurally distinct contact regions between Kenyon cells and dopaminergic, serotonergic, and octopaminergic/tyraminergic neurons in all subdivisions of the mushroom body. Subpopulations of dopaminergic neurons contact complementary lobe regions densely. Octopaminergic/tyraminergic neurons contact Kenyon cells sparsely and are restricted mainly to the calyx, the -lobes, and the -lobes. Contacts of Kenyon cells with serotonergic neurons are heterogeneously distributed over the entire mushroom body. In summary, the technique enables us to localize precisely a segmentation of the mushroom body by differential contacts with aminergic neurons. J. Comp. Neurol. 521:3992-4026, 2013. (c) 2013 Wiley Periodicals, Inc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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