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https://www.readbyqxmd.com/read/28448253/a-map-of-abstract-relational-knowledge-in-the-human-hippocampal-entorhinal-cortex
#1
Mona M Garvert, Raymond J Dolan, Timothy Ej Behrens
The hippocampal-entorhinal system encodes a map of space that guides spatial navigation. Goal-directed behaviour outside of spatial navigation similarly requires a representation of abstract forms of relational knowledge. This information relies on the same neural system, but it is not known whether the organisational principles governing continuous maps may extend to the implicit encoding of discrete, non-spatial graphs. Here, we show that the human hippocampal-entorhinal system can represent relationships between objects using a metric that depends on associative strength...
April 27, 2017: ELife
https://www.readbyqxmd.com/read/28424398/-brodmann-areas-27-28-36-and-37-the-parahippocampal-and-the-fusiform-gyri
#2
Satoshi Eifuku
First, Brodmann areas 27, 28, 36 and 37, were anatomically defined in the beginning of this review. These areas exist in the parahippocampal or fusiform gyrus of the ventral temporal lobe in humans. Subsequently, the current understanding of their functions was summarized on the basis of recent findings mainly through human functional neuroimaging studies and animal studies. Rodent studies have shown the existence of neuronal activities for representing space, such as those involving head-direction cells or grid cells, in areas 27 (the parasubicular cortex) and 28 (the ventral entorhinal cortex)...
April 2017: Brain and Nerve, Shinkei Kenkyū No Shinpo
https://www.readbyqxmd.com/read/28418593/nonparametric-tree-based-predictive-modeling-of-storm-outages-on-an-electric-distribution-network
#3
Jichao He, David W Wanik, Brian M Hartman, Emmanouil N Anagnostou, Marina Astitha, Maria E B Frediani
This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF...
March 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/28396399/context-dependent-spatially-periodic-activity-in-the-human-entorhinal-cortex
#4
Zoltan Nadasdy, T Peter Nguyen, Ágoston Török, Jason Y Shen, Deborah E Briggs, Pradeep N Modur, Robert J Buchanan
The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60° rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents...
April 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28392071/a-multiplexed-heterogeneous-and-adaptive-code-for-navigation-in-medial-entorhinal-cortex
#5
Kiah Hardcastle, Niru Maheswaranathan, Surya Ganguli, Lisa M Giocomo
Medial entorhinal grid cells display strikingly symmetric spatial firing patterns. The clarity of these patterns motivated the use of specific activity pattern shapes to classify entorhinal cell types. While this approach successfully revealed cells that encode boundaries, head direction, and running speed, it left a majority of cells unclassified, and its pre-defined nature may have missed unconventional, yet important coding properties. Here, we apply an unbiased statistical approach to search for cells that encode navigationally relevant variables...
April 19, 2017: Neuron
https://www.readbyqxmd.com/read/28380248/development-of-an-asset-value-map-for-disaster-risk-assessment-in-china-by-spatial-disaggregation-using-ancillary-remote-sensing-data
#6
Jidong Wu, Ying Li, Ning Li, Peijun Shi
The extent of economic losses due to a natural hazard and disaster depends largely on the spatial distribution of asset values in relation to the hazard intensity distribution within the affected area. Given that statistical data on asset value are collected by administrative units in China, generating spatially explicit asset exposure maps remains a key challenge for rapid postdisaster economic loss assessment. The goal of this study is to introduce a top-down (or downscaling) approach to disaggregate administrative-unit level asset value to grid-cell level...
April 5, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/28371135/climate-and-geochemistry-as-drivers-of-eucalypt-diversification-in-australia
#7
E N Bui, A H Thornhill, C E González-Orozco, N Knerr, J T Miller
Eucalypts cover most of Australia. Here, we investigate the relative contribution of climate and geochemistry to the distribution and diversity of eucalypts. Using geostatistics, we estimate major element concentrations, pH, and electrical conductivity at sites where eucalypts have been recorded. We compare the median predicted geochemistry and reported substrate for individual species that appear associated with extreme conditions; this provides a partial evaluation of the predictions. We generate a site-by-species matrix by aggregating observations to the centroids of 100-km-wide grid cells, calculate diversity indices, and use numerical ecology methods (ordination, variation partitioning) to investigate the ecology of eucalypts and their response to climatic and geochemical gradients...
May 2017: Geobiology
https://www.readbyqxmd.com/read/28370671/multiscale-mapping-of-species-diversity-under-changed-land-use-using-imaging-spectroscopy
#8
Tarin Paz-Kagan, Tamir Caras, Ittai Herrmann, Moshe Shachak, Arnon Karnieli
Land-use changes are one of the most important factors causing environmental transformations and species diversity alterations. The aim of the current study was to develop a geoinformatics-based framework to quantify alpha and beta diversity indices in two sites in Israel with different land-uses, i.e., an agricultural system of fruit orchards, an afforestation system of planted groves, and an unmanaged system of groves. The framework comprises four scaling steps: (1) classification of a tree species distribution (SD) map using imaging spectroscopy (IS) at a pixel size of 1 m; (2) estimation of local species richness by calculating the alpha diversity index for 30-m grid cells; (3) calculation of beta diversity for different land-use categories and sub-categories at different sizes; and (4) calculation of the beta diversity difference between the two sites...
March 28, 2017: Ecological Applications: a Publication of the Ecological Society of America
https://www.readbyqxmd.com/read/28362872/evaluating-methods-for-estimating-home-ranges-using-gps-collars-a-comparison-using-proboscis-monkeys-nasalis-larvatus
#9
Danica J Stark, Ian P Vaughan, Diana A Ramirez Saldivar, Senthilvel K S S Nathan, Benoit Goossens
The development of GPS tags for tracking wildlife has revolutionised the study of home ranges, habitat use and behaviour. Concomitantly, there have been rapid developments in methods for estimating habitat use from GPS data. In combination, these changes can cause challenges in choosing the best methods for estimating home ranges. In primatology, this issue has received little attention, as there have been few GPS collar-based studies to date. However, as advancing technology is making collaring studies more feasible, there is a need for the analysis to advance alongside the technology...
2017: PloS One
https://www.readbyqxmd.com/read/28358077/mapping-of-a-non-spatial-dimension-by-the-hippocampal-entorhinal-circuit
#10
Dmitriy Aronov, Rhino Nevers, David W Tank
During spatial navigation, neural activity in the hippocampus and the medial entorhinal cortex (MEC) is correlated to navigational variables such as location, head direction, speed, and proximity to boundaries. These activity patterns are thought to provide a map-like representation of physical space. However, the hippocampal-entorhinal circuit is involved not only in spatial navigation, but also in a variety of memory-guided behaviours. The relationship between this general function and the specialized spatial activity patterns is unclear...
March 29, 2017: Nature
https://www.readbyqxmd.com/read/28344929/comparing-regional-precipitation-and-temperature-extremes-in-climate-model-and-reanalysis-products
#11
Oliver Angélil, Sarah Perkins-Kirkpatrick, Lisa V Alexander, Dáithí Stone, Markus G Donat, Michael Wehner, Hideo Shiogama, Andrew Ciavarella, Nikolaos Christidis
A growing field of research aims to characterise the contribution of anthropogenic emissions to the likelihood of extreme weather and climate events. These analyses can be sensitive to the shapes of the tails of simulated distributions. If tails are found to be unrealistically short or long, the anthropogenic signal emerges more or less clearly, respectively, from the noise of possible weather. Here we compare the chance of daily land-surface precipitation and near-surface temperature extremes generated by three Atmospheric Global Climate Models typically used for event attribution, with distributions from six reanalysis products...
September 2016: Weather and Climate Extremes
https://www.readbyqxmd.com/read/28343867/grid-and-nongrid-cells-in-medial-entorhinal-cortex-represent-spatial-location-and-environmental-features-with-complementary-coding-schemes
#12
Geoffrey W Diehl, Olivia J Hon, Stefan Leutgeb, Jill K Leutgeb
The medial entorhinal cortex (mEC) has been identified as a hub for spatial information processing by the discovery of grid, border, and head-direction cells. Here we find that in addition to these well-characterized classes, nearly all of the remaining two-thirds of mEC cells can be categorized as spatially selective. We refer to these cells as nongrid spatial cells and confirmed that their spatial firing patterns were unrelated to running speed and highly reproducible within the same environment. However, in response to manipulations of environmental features, such as box shape or box color, nongrid spatial cells completely reorganized their spatial firing patterns...
April 5, 2017: Neuron
https://www.readbyqxmd.com/read/28334142/layer-specific-organization-of-local-excitatory-and-inhibitory-synaptic-connectivity-in-the-rat-presubiculum
#13
Yangfan Peng, Federico J Barreda Tomás, Constantin Klisch, Imre Vida, Jörg R P Geiger
The presubiculum is part of the parahippocampal spatial navigation system and contains head direction and grid cells upstream of the medial entorhinal cortex. This position within the parahippocampal cortex renders the presubiculum uniquely suited for analyzing the circuit requirements underlying the emergence of spatially tuned neuronal activity. To identify the local circuit properties, we analyzed the topology of synaptic connections between pyramidal cells and interneurons in all layers of the presubiculum by testing 4250 potential synaptic connections using multiple whole-cell recordings of up to 8 cells simultaneously...
April 1, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28314046/analysis-of-traffic-crashes-involving-pedestrians-using-big-data-investigation-of-contributing-factors-and-identification-of-hotspots
#14
Kun Xie, Kaan Ozbay, Abdullah Kurkcu, Hong Yang
This study aims to explore the potential of using big data in advancing the pedestrian risk analysis including the investigation of contributing factors and the hotspot identification. Massive amounts of data of Manhattan from a variety of sources were collected, integrated, and processed, including taxi trips, subway turnstile counts, traffic volumes, road network, land use, sociodemographic, and social media data. The whole study area was uniformly split into grid cells as the basic geographical units of analysis...
March 17, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/28302156/mapping-the-spatial-distribution-of-the-japanese-encephalitis-vector-culex-tritaeniorhynchus-giles-1901-diptera-culicidae-within-areas-of-japanese-encephalitis-risk
#15
Joshua Longbottom, Annie J Browne, David M Pigott, Marianne E Sinka, Nick Golding, Simon I Hay, Catherine L Moyes, Freya M Shearer
BACKGROUND: Japanese encephalitis (JE) is one of the most significant aetiological agents of viral encephalitis in Asia. This medically important arbovirus is primarily spread from vertebrate hosts to humans by the mosquito vector Culex tritaeniorhynchus. Knowledge of the contemporary distribution of this vector species is lacking, and efforts to define areas of disease risk greatly depend on a thorough understanding of the variation in this mosquito's geographical distribution. RESULTS: We assembled a contemporary database of Cx...
March 16, 2017: Parasites & Vectors
https://www.readbyqxmd.com/read/28270783/semi-supervised-learning-of-cartesian-factors-a-top-down-model-of-the-entorhinal-hippocampal-complex
#16
András Lőrincz, András Sárkány
The existence of place cells (PCs), grid cells (GCs), border cells (BCs), and head direction cells (HCs) as well as the dependencies between them have been enigmatic. We make an effort to explain their nature by introducing the concept of Cartesian Factors. These factors have specific properties: (i) they assume and complement each other, like direction and position and (ii) they have localized discrete representations with predictive attractors enabling implicit metric-like computations. In our model, HCs make the distributed and local representation of direction...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/28268589/place-field-detection-using-grid-based-clustering-in-a-large-scale-computational-model-of-the-rat-dentate-gyrus
#17
Gene J Yu, Dong Song, Theodore W Berger
Place cells are neurons in the hippocampus that are sensitive to location within an environment. Simulations of a large-scale, computational model of the rat dentate gyrus using grid cell input have been performed resulting in granule cells that express multiple place fields. The typical method of detecting place fields using a global threshold on this data is unreliable as the characteristics of the place fields from a single neuron can be highly variable. A grid-based implementation of DENCLUE has been developed to calculate local thresholds to identify each place field...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28262363/mapping-landslide-susceptibility-using-data-driven-methods
#18
J L Zêzere, S Pereira, R Melo, S C Oliveira, R A C Garcia
Most epistemic uncertainty within data-driven landslide susceptibility assessment results from errors in landslide inventories, difficulty in identifying and mapping landslide causes and decisions related with the modelling procedure. In this work we evaluate and discuss differences observed on landslide susceptibility maps resulting from: (i) the selection of the statistical method; (ii) the selection of the terrain mapping unit; and (iii) the selection of the feature type to represent landslides in the model (polygon versus point)...
March 2, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28253272/risk-mapping-of-clonorchiasis-in-the-people-s-republic-of-china-a-systematic-review-and-bayesian-geostatistical-analysis
#19
Ying-Si Lai, Xiao-Nong Zhou, Zhi-Heng Pan, Jürg Utzinger, Penelope Vounatsou
BACKGROUND: Clonorchiasis, one of the most important food-borne trematodiases, affects more than 12 million people in the People's Republic of China (P.R. China). Spatially explicit risk estimates of Clonorchis sinensis infection are needed in order to target control interventions. METHODOLOGY: Georeferenced survey data pertaining to infection prevalence of C. sinensis in P.R. China from 2000 onwards were obtained via a systematic review in PubMed, ISI Web of Science, Chinese National Knowledge Internet, and Wanfang Data from January 1, 2000 until January 10, 2016, with no restriction of language or study design...
March 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28244115/finely-resolved-on-road-pm2-5-and-estimated-premature-mortality-in-central-north-carolina
#20
Shih Ying Chang, William Vizuete, Marc Serre, Lakshmi Pradeepa Vennam, Mohammad Omary, Vlad Isakov, Michael Breen, Saravanan Arunachalam
To quantify the on-road PM2.5 -related premature mortality at a national scale, previous approaches to estimate concentrations at a 12-km × 12-km or larger grid cell resolution may not fully characterize concentration hotspots that occur near roadways and thus the areas of highest risk. Spatially resolved concentration estimates from on-road emissions to capture these hotspots may improve characterization of the associated risk, but are rarely used for estimating premature mortality. In this study, we compared the on-road PM2...
February 28, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
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