Entorhinal neurons exhibit cue locking in rodent VR

The regular firing pattern exhibited by medial entorhinal (mEC) grid cells of locomoting rodents is hypothesized to provide spatial metric information relevant for navigation. The development of virtual reality (VR) for head-fixed mice confers a number of experimental advantages and has become increasingly popular as a method for investigating spatiallyselective cells. Recent experiments using 1D VR linear tracks have shown that some mEC cells have multiple fields in virtual space, analogous to grid cells on real linear tracks. We recorded from the mEC as mice traversed virtual tracks featuring regularly spaced repetitive cues and identified a population of cells with multiple firing fields, resembling the regular firing of grid cells. However, further analyses indicated that many of these were not, in fact, grid cells because: (1) when recorded in the open field they did not display discrete firing fields with six-fold symmetry; and (2) in different VR environments their firing fields were found to match the spatial frequency of repetitive environmental cues. In contrast, cells identified as grid cells based on their open field firing patterns did not exhibit cue locking. In light of these results we highlight the importance of controlling the periodicity of the visual cues in VR and the necessity of identifying grid cells from real open field environments in order to correctly characterize spatially modulated neurons in VR experiments

Entorhinal Neurons Exhibit Cue Locking in Rodent VR

The regular firing pattern exhibited by medial entorhinal (mEC) grid cells of locomoting rodents is hypothesized to provide spatial metric information relevant for navigation. The development of virtual reality (VR) for head-fixed mice confers a number of experimental advantages and has become increasingly popular as a method for investigating spatially-selective cells. Recent experiments using 1D VR linear tracks have shown that some mEC cells have multiple fields in virtual space, analogous to grid cells on real linear tracks. We recorded from the mEC as mice traversed virtual tracks featuring regularly spaced repetitive cues and identified a population of cells with multiple firing fields, resembling the regular firing of grid cells. However, further analyses indicated that many of these were not, in fact, grid cells because: (1) when recorded in the open field they did not display discrete firing fields with six-fold symmetry; and (2) in different VR environments their firing fields were found to match the spatial frequency of repetitive environmental cues. In contrast, cells identified as grid cells based on their open field firing patterns did not exhibit cue locking. In light of these results we highlight the importance of controlling the periodicity of the visual cues in VR and the necessity of identifying grid cells from real open field environments in order to correctly characterize spatially modulated neurons in VR experiments

[United States Soil Survey Report]

Text describes the area, climate, agricultural history and statistics, soil-survey methods and definitions, soils and crops, land uses and agricultural methods, irrigation, and morphology and genesis of soils of Jack County, Texas

THE DUKES OF DIXIELAND : vol. 2 / the Dukes of Dixieland

Titre uniforme : [Ain't she sweet]Titre uniforme : [My blue heaven]Titre uniforme : [The Sheik of Araby]Titre uniforme : [Sweet Georgia Brown]Titre uniforme : [Limehouse blues]Titre uniforme : [My blue heaven]Titre uniforme : [Limehouse blues]Comprend : SWEET GEORGIA BROWN / Pinkard ; Bernie ; Casey - SLIDE, FROG, SLIDE / Assunto ; Frey - DILL PICKLES / Johnson ; chant. Assunto - BASIN STREET BLUES / Williams - MY BLUE HEAVEN / Donaldson ; Whiting ; chantBetty Owens - SHEIK OF ARABY / Snyder - MAMA DON' LOW / trad. arr. Assunto ; Frey - MOCKING BIRD / arr. Assunto ; Frey - LIMEHOUSE BLUES / Braham ; Furber - THAT DA DA STRAIN / Medina ; Dowell - GO BACK WHERE YOU STAYED / Betty Owens, chant ; Assunto ; Frey - AIN'T SHE SWEET ? / Yellen ; Ager ; BernsteinBnF-Partenariats, Collection sonore - BelieveContient une table des matière

Reproducibility of fluorescent expression from engineered biological constructs in E. coli

We present results of the first large-scale interlaboratory study carried out in synthetic biology, as part of the 2014 and 2015 International Genetically Engineered Machine (iGEM) competitions. Participants at 88 institutions around the world measured fluorescence from three engineered constitutive constructs in E. coli. Few participants were able to measure absolute fluorescence, so data was analyzed in terms of ratios. Precision was strongly related to fluorescent strength, ranging from 1.54-fold standard deviation for the ratio between strong promoters to 5.75-fold for the ratio between the strongest and weakest promoter, and while host strain did not affect expression ratios, choice of instrument did. This result shows that high quantitative precision and reproducibility of results is possible, while at the same time indicating areas needing improved laboratory practices.Peer reviewe