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190 Janelia Publications

Showing 81-90 of 190 results
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    Ahrens LabLooger LabKeller LabFreeman Lab
    07/27/14 | Light-sheet functional imaging in fictively behaving zebrafish.
    Vladimirov N, Mu Y, Kawashima T, Bennett DV, Yang C, Looger LL, Keller PJ, Freeman J, Ahrens MB
    Nature Methods. 2014 Jul 27;11(9):883-4. doi: 10.1038/nmeth.3040

    The processing of sensory input and the generation of behavior involves large networks of neurons, which necessitates new technology for recording from many neurons in behaving animals. In the larval zebrafish, light-sheet microscopy can be used to record the activity of almost all neurons in the brain simultaneously at single-cell resolution. Existing implementations, however, cannot be combined with visually driven behavior because the light sheet scans over the eye, interfering with presentation of controlled visual stimuli. Here we describe a system that overcomes the confounding eye stimulation through the use of two light sheets and combines whole-brain light-sheet imaging with virtual reality for fictively behaving larval zebrafish.

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    Looger LabAhrens LabFreeman LabSvoboda Lab
    07/27/14 | Mapping brain activity at scale with cluster computing.
    Freeman J, Vladimirov N, Kawashima T, Mu Y, Sofroniew NJ, Bennett DV, Rosen J, Yang C, Looger LL, Ahrens MB
    Nature Methods. 2014 Jul 27;11(9):941-950. doi: 10.1038/nmeth.3041

    Understanding brain function requires monitoring and interpreting the activity of large networks of neurons during behavior. Advances in recording technology are greatly increasing the size and complexity of neural data. Analyzing such data will pose a fundamental bottleneck for neuroscience. We present a library of analytical tools called Thunder built on the open-source Apache Spark platform for large-scale distributed computing. The library implements a variety of univariate and multivariate analyses with a modular, extendable structure well-suited to interactive exploration and analysis development. We demonstrate how these analyses find structure in large-scale neural data, including whole-brain light-sheet imaging data from fictively behaving larval zebrafish, and two-photon imaging data from behaving mouse. The analyses relate neuronal responses to sensory input and behavior, run in minutes or less and can be used on a private cluster or in the cloud. Our open-source framework thus holds promise for turning brain activity mapping efforts into biological insights.

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    07/24/14 | Looking under the lamp post: neither fruitless nor doublesex has evolved to generate divergent male courtship in Drosophila.
    Cande J, Stern DL, Morita T, Prud'homme B, Gompel N
    Cell Reports. 2014 Jul 24;8(2):363-70. doi: 10.1016/j.celrep.2014.06.023

    How do evolved genetic changes alter the nervous system to produce different patterns of behavior? We address this question using Drosophila male courtship behavior, which is innate, stereotyped, and evolves rapidly between species. D. melanogaster male courtship requires the male-specific isoforms of two transcription factors, fruitless and doublesex. These genes underlie genetic switches between female and male behaviors, making them excellent candidate genes for courtship behavior evolution. We tested their role in courtship evolution by transferring the entire locus for each gene from divergent species to D. melanogaster. We found that despite differences in Fru+ and Dsx+ cell numbers in wild-type species, cross-species transgenes rescued D. melanogaster courtship behavior and no species-specific behaviors were conferred. Therefore, fru and dsx are not a significant source of evolutionary variation in courtship behavior.

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    07/22/14 | Optimized CRISPR/Cas tools for efficient germline and somatic genome engineering in Drosophila.
    Port F, Chen H, Lee T, Bullock SL
    Proceedings of the National Academy of Sciences of the United States of America. 2014 Jul 22;111(29):E2967-76. doi: 10.1073/pnas.1405500111

    The type II clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system has emerged recently as a powerful method to manipulate the genomes of various organisms. Here, we report a toolbox for high-efficiency genome engineering of Drosophila melanogaster consisting of transgenic Cas9 lines and versatile guide RNA (gRNA) expression plasmids. Systematic evaluation reveals Cas9 lines with ubiquitous or germ-line-restricted patterns of activity. We also demonstrate differential activity of the same gRNA expressed from different U6 snRNA promoters, with the previously untested U6:3 promoter giving the most potent effect. An appropriate combination of Cas9 and gRNA allows targeting of essential and nonessential genes with transmission rates ranging from 25-100%. We also demonstrate that our optimized CRISPR/Cas tools can be used for offset nicking-based mutagenesis. Furthermore, in combination with oligonucleotide or long double-stranded donor templates, our reagents allow precise genome editing by homology-directed repair with rates that make selection markers unnecessary. Last, we demonstrate a novel application of CRISPR/Cas-mediated technology in revealing loss-of-function phenotypes in somatic cells following efficient biallelic targeting by Cas9 expressed in a ubiquitous or tissue-restricted manner. Our CRISPR/Cas tools will facilitate the rapid evaluation of mutant phenotypes of specific genes and the precise modification of the genome with single-nucleotide precision. Our results also pave the way for high-throughput genetic screening with CRISPR/Cas.

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    07/21/14 | Abdominal-B neurons control Drosophila virgin female receptivity.
    Bussell JJ, Yapici N, Zhang SX, Dickson BJ, Vosshall LB
    Current Biology. 2014 Jul 21;24(14):1584-95. doi: 10.1016/j.cub.2014.06.011

    BACKGROUND: Female sexual receptivity offers an excellent model for complex behavioral decisions. The female must parse her own reproductive state, the external environment, and male sensory cues to decide whether to copulate. In the fly Drosophila melanogaster, virgin female receptivity has received relatively little attention, and its neural circuitry and individual behavioral components remain unmapped. Using a genome-wide neuronal RNAi screen, we identify a subpopulation of neurons responsible for pausing, a novel behavioral aspect of virgin female receptivity characterized in this study.

    RESULTS: We show that Abdominal-B (Abd-B), a homeobox transcription factor, is required in developing neurons for high levels of virgin female receptivity. Silencing adult Abd-B neurons significantly decreased receptivity. We characterize two components of receptivity that are elicited in sexually mature females by male courtship: pausing and vaginal plate opening. Silencing Abd-B neurons decreased pausing but did not affect vaginal plate opening, demonstrating that these two components of female sexual behavior are functionally separable. Synthetic activation of Abd-B neurons increased pausing, but male courtship song alone was not sufficient to elicit this behavior.

    CONCLUSIONS: Our results provide an entry point to the neural circuit controlling virgin female receptivity. The female integrates multiple sensory cues from the male to execute discrete motor programs prior to copulation. Abd-B neurons control pausing, a key aspect of female sexual receptivity, in response to male courtship.

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    07/20/14 | Fast, accurate reconstruction of cell lineages from large-scale fluorescence microscopy data.
    Amat F, Lemon W, Mossing DP, McDole K, Wan Y, Branson K, Myers EW, Keller PJ
    Nature Methods. 2014 Jul 20;11(9):951-8. doi: 10.1038/nmeth.3036

    The comprehensive reconstruction of cell lineages in complex multicellular organisms is a central goal of developmental biology. We present an open-source computational framework for the segmentation and tracking of cell nuclei with high accuracy and speed. We demonstrate its (i) generality by reconstructing cell lineages in four-dimensional, terabyte-sized image data sets of fruit fly, zebrafish and mouse embryos acquired with three types of fluorescence microscopes, (ii) scalability by analyzing advanced stages of development with up to 20,000 cells per time point at 26,000 cells min(-1) on a single computer workstation and (iii) ease of use by adjusting only two parameters across all data sets and providing visualization and editing tools for efficient data curation. Our approach achieves on average 97.0% linkage accuracy across all species and imaging modalities. Using our system, we performed the first cell lineage reconstruction of early Drosophila melanogaster nervous system development, revealing neuroblast dynamics throughout an entire embryo.

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    07/18/14 | Precise spatial coding is preserved along the longitudinal hippocampal axis.
    Keinath AT, Wang ME, Wann EG, Yuan RK, Dudman JT, Muzzio IA
    Hippocampus. 2014 Jul 18;24(12):1-16. doi: 10.1002/hipo.22333

    Compared to the dorsal hippocampus, relatively few studies have characterized neuronal responses in the ventral hippocampus. In particular, it is unclear whether and how cells in the ventral region represent space and/or respond to contextual changes. We recorded from dorsal and ventral CA1 neurons in freely moving mice exposed to manipulations of visuospatial and olfactory contexts. We found that ventral cells respond to alterations of the visuospatial environment such as exposure to novel local cues, cue rotations, and contextual expansion in similar ways to dorsal cells, with the exception of cue rotations. Furthermore, we found that ventral cells responded to odors much more strongly than dorsal cells, particularly to odors of high valence. Similar to earlier studies recording from the ventral hippocampus in CA3, we also found increased scaling of place cell field size along the longitudinal hippocampal axis. Although the increase in place field size observed toward the ventral pole has previously been taken to suggest a decrease in spatial information coded by ventral place cells, we hypothesized that a change in spatial scaling could instead signal a shift in representational coding that preserves the resolution of spatial information. To explore this possibility, we examined population activity using principal component analysis (PCA) and neural location reconstruction techniques. Our results suggest that ventral populations encode a distributed representation of space, and that the resolution of spatial information at the population level is comparable to that of dorsal populations of similar size. Finally, through the use of neural network modeling, we suggest that the redundancy in spatial representation along the longitudinal hippocampal axis may allow the hippocampus to overcome the conflict between memory interference and generalization inherent in neural network memory. Our results suggest that ventral population activity is well suited for generalization across locations and contexts. © 2014 Wiley Periodicals, Inc.

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    Card LabLeonardo Lab
    07/17/14 | A spike-timing mechanism for action selection.
    von Reyn CR, Breads P, Peek MY, Zheng GZ, Williamson WR, Yee AL, Leonardo A, Card GM
    Nature Neuroscience. 2014 Jul 17;17(7):962-70. doi: 10.1038/nn.3741

    We discovered a bimodal behavior in the genetically tractable organism Drosophila melanogaster that allowed us to directly probe the neural mechanisms of an action selection process. When confronted by a predator-mimicking looming stimulus, a fly responds with either a long-duration escape behavior sequence that initiates stable flight or a distinct, short-duration sequence that sacrifices flight stability for speed. Intracellular recording of the descending giant fiber (GF) interneuron during head-fixed escape revealed that GF spike timing relative to parallel circuits for escape actions determined which of the two behavioral responses was elicited. The process was well described by a simple model in which the GF circuit has a higher activation threshold than the parallel circuits, but can override ongoing behavior to force a short takeoff. Our findings suggest a neural mechanism for action selection in which relative activation timing of parallel circuits creates the appropriate motor output.

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    Menon Lab
    07/16/14 | A high-resolution spatiotemporal atlas of gene expression of the developing mouse brain.
    Thompson CL, Ng L, Menon V, Martinez S, Lee C, Glattfelder K, Sunkin SM, Henry A, Lau C, Dang C, Garcia-Lopez R, Martinez-Ferre A, Pombero A, Rubenstein JL, Wakeman WB, Hohmann J, Dee N, Sodt AJ, Young R, Smith K, Nguyen T, Kidney J, Kuan L, Jeromin A, Kaykas A, Miller J, Page D, Orta G, Bernard A, Riley Z, Smith S, Wohnoutka P, Hawrylycz MJ, Puelles L, Jones AR
    Neuron. 2014 Jul 16;83(2):309-23. doi: 10.1016/j.neuron.2014.05.033

    To provide a temporal framework for the genoarchitecture of brain development, we generated in situ hybridization data for embryonic and postnatal mouse brain at seven developmental stages for ∼2,100 genes, which were processed with an automated informatics pipeline and manually annotated. This resource comprises 434,946 images, seven reference atlases, an ontogenetic ontology, and tools to explore coexpression of genes across neurodevelopment. Gene sets coinciding with developmental phenomena were identified. A temporal shift in the principles governing the molecular organization of the brain was detected, with transient neuromeric, plate-based organization of the brain present at E11.5 and E13.5. Finally, these data provided a transcription factor code that discriminates brain structures and identifies the developmental age of a tissue, providing a foundation for eventual genetic manipulation or tracking of specific brain structures over development. The resource is available as the Allen Developing Mouse Brain Atlas (http://developingmouse.brain-map.org).

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    07/16/14 | Accessing the third dimension in localization-based super-resolution microscopy.
    Hajj B, El Beheiry M, Izeddin I, Darzacq X, Dahan M
    Physical Chemistry Chemical Physics. 2014 Jul 16;16(31):16340-8. doi: 10.1039/c4cp01380h

    Only a few years after its inception, localization-based super-resolution microscopy has become widely employed in biological studies. Yet, it is primarily used in two-dimensional imaging and accessing the organization of cellular structures at the nanoscale in three dimensions (3D) still poses important challenges. Here, we review optical and computational techniques that enable the 3D localization of individual emitters and the reconstruction of 3D super-resolution images. These techniques are grouped into three main categories: PSF engineering, multiple plane imaging and interferometric approaches. We provide an overview of their technical implementation as well as commentary on their applicability. Finally, we discuss future trends in 3D localization-based super-resolution microscopy.

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