50 research outputs found

    Geniculo-Cortical Projection Diversity Revealed within the Mouse Visual Thalamus

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    This is the final version of the article. It was first available from PLOS via http://dx.doi.org/10.1371/journal.pone.0144846All dLGN cell co-ordinates, V1 injection sites, dLGN boundary coordinates, experimental protocols and analysis scripts are available for download from figshare at https://figshare.com/s/36c6d937b1844eec80a1.The mouse dorsal lateral geniculate nucleus (dLGN) is an intermediary between retina and primary visual cortex (V1). Recent investigations are beginning to reveal regional complexity in mouse dLGN. Using local injections of retrograde tracers into V1 of adult and neonatal mice, we examined the developing organisation of geniculate projection columns: the population of dLGN-V1 projection neurons that converge in cortex. Serial sectioning of the dLGN enabled the distribution of labelled projection neurons to be reconstructed and collated within a common standardised space. This enabled us to determine: the organisation of cells within the dLGN-V1 projection columns; their internal organisation (topology); and their order relative to V1 (topography). Here, we report parameters of projection columns that are highly variable in young animals and refined in the adult, exhibiting profiles consistent with shell and core zones of the dLGN. Additionally, such profiles are disrupted in adult animals with reduced correlated spontaneous activity during development. Assessing the variability between groups with partial least squares regression suggests that 4?6 cryptic lamina may exist along the length of the projection column. Our findings further spotlight the diversity of the mouse dLGN?an increasingly important model system for understanding the pre-cortical organisation and processing of visual information. Furthermore, our approach of using standardised spaces and pooling information across many animals will enhance future functional studies of the dLGN.Funding was provided by a Wellcome Trust grant jointly awarded to IDT and SJE (083205, www.wellcome.ac.uk), and by MRC PhD Studentships awarded to MNL and ACH (http://www.mrc.ac.uk/)

    Protecting an estuary from floods: A policy analysis of the Oosterschelde. Vol 2: Assessment of security from flooding

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    The second volume in a series of reports describing the methodology and results of a joint research venture between RAND and the Netherlands Rijkswaterstaat. The POLANO project was founded to help the Dutch government analyze the different alternatives (open, closed, and storm-surge barrier cases) for protecting the Oosterschelde region from North Sea floods. Volume II describes the methodology developed to estimate the likelihood and severity of flood damage to people, property, and land under each of the alternatives. These are subjected to many simulated threats expressed in terms of storm water levels. The methodology's damage estimates compared favorably with the actual damage observed in a severe 1953 storm. Also assessed is the reliability of the storm-surge barrier. The report demonstrates how security varies, in both the long-run and construction periods, with changes in the alternatives and assumptions.Polan
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