188 research outputs found
Analysis of Activity Dependent Development of Topographic Maps in Neural Field Theory with Short Time Scale Dependent Plasticity
Topographic maps are a brain structure connecting pre-synpatic and
post-synaptic brain regions. Topographic development is dependent on
Hebbian-based plasticity mechanisms working in conjunction with spontaneous
patterns of neural activity generated in the pre-synaptic regions. Studies
performed in mouse have shown that these spontaneous patterns can exhibit
complex spatial-temporal structures which existing models cannot incorporate.
Neural field theories are appropriate modelling paradigms for topographic
systems due to the dense nature of the connections between regions and can be
augmented with a plasticity rule general enough to capture complex time-varying
structures.
We propose a theoretical framework for studying the development of topography
in the context of complex spatial-temporal activity fed-forward from the
pre-synaptic to post-synaptic regions. Analysis of the model leads to an
analytic solution corroborating the conclusion that activity can drive the
refinement of topographic projections. The analysis also suggests that
biological noise is used in the development of topography to stabilise the
dynamics. MCMC simulations are used to analyse and understand the differences
in topographic refinement between wild-type and the knock-out mutant
in mice. The time scale of the synaptic plasticity window is estimated as
seconds in this context with a model fit of .</jats:p
Predictors of Implantable Pulse Generator Placement After Sacral Neuromodulation: Who Does Better?
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107552/1/ner12109.pd
Association between temperament related traits and SNPs in the serotonin and oxytocin systems in Merino sheep
ABSTRACT Animal temperament is defined as the consistent behavioral and physiological differences that are seen between individuals in response to the same stressor. Neurotransmitter systems, like serotonin and oxytocin in the central nervous system, underlie variation in behavioral traits in humans and other animals. Variations like single nucleotide polymorphisms (SNPs) in the genes for tryptophan 5-hydroxylase (TPH2), the serotonin transporter (SLC6A4), the serotonin receptor (HTR2A), and the oxytocin receptor (OXTR) are associated with behavioral phenotype in humans. Thus, the objective of this study was to identify SNPs in those genes and to test if those variations are associated with the temperament in Merino sheep. Using ewes from the University of Western Australia temperament flock, that has been selected on emotional reactivity for more than 20 generations, eight SNPs (rs107856757, rs107856818, rs107856856 and rs107857156 in TPH2, rs20917091 in SLC6A4, rs17196799 and rs17193181 in HTR2A, and rs17664565 in OXTR) were found to be distributed differently between calm and nervous sheep. These eight SNPs were then genotyped in 260 sheep from a flock that has never been selected on emotional reactivity, followed by the estimation of the behavioral traits of those 260 sheep using an arena test and an isolation box test. We found that several SNPs in TPH2 (rs107856757, rs107856818, rs107856856 and rs107857156) were in strong linkage disequilibrium, and all were associated with behavioral phenotype in the non-selected sheep. Similarly, rs17196799 in HTR2A was also associated with the behavioral phenotype
Outcomes of Sacral Neuromodulation in a Privately Insured Population
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134200/1/ner12472_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134200/2/ner12472.pd
The Effect of Sacral Neuromodulation on Anticholinergic Use and Expenditures in a Privately Insured Population
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106102/1/ner12062.pd
Signal Appropriation of Explicit HIV Status Disclosure Fields in Sex-Social Apps used by Gay and Bisexual Men
HIV status disclosure fields in online sex-social applications ("apps") are designed to help increase awareness, reduce stigma, and promote sexual health. Public disclosure could also help those diagnosed relate to others with similar statuses to feel less isolated. However, in our interview study (n=28) with HIV positive and negative men who have sex with men (MSM), we found some users preferred to keep their status private, especially when disclosure could stigmatise and disadvantage them, or risk revealing their status to someone they knew offline in a different context. How do users manage these tensions between health, stigma, and privacy? We analysed our interview data using signalling theory as a conceptual framework and identify participants developing 'signal appropriation' strategies, helping them manage the disclosure of their HIV status. Additionally, we propose a set of design considerations that explore the use of signals in the design of sensitive disclosure fields
A Re-Examination of the Taxonomic Boundaries of \u3cem\u3eSymphysia\u3c/em\u3e (Ericaceae)
DNA sequence data were generated for the nuclear ITS region for Symphysia racemosa and for 26 additional Vaccinieae representing 12 sections in the genus Vaccinium plus one species from each of five additional segregate genera. Our focus is on the placement of S. racemosa relative to Vaccinium sensu scricto and Vaccinium sect. Oreades (represented by V. poasanum). Maximum parsimony analysis of 608 bp of nrITS region suggests that S. racemosa and V. poasanum form a well-supported clade in spite of substantial morphological divergence. Futhermore, this clade is a sister group to a clade consisting of all segregate genera examined. These molecular results led us to undertake a morphological cladistic analysis of all of the other Central American green-flowered taxa. We suggest that the genus Symphysia should be expanded to encompass these 15 taxa, despite the lack of phylogenetic resolution within this group. This will necessitate eight new combinations, via. Symphysia almedae (= V. almedae), Symphysia costaricensis (= V. costaricense), Symphysia jefensis (= V. jefense), Symphysia orosiensis (= V. orosiense), Symphysia ovata (= Lateropora ovata), Symphysia perardua (= V. santafeënsis), Symphysia poasana (= Vaccinium poasanum), Symphysia santafeënsis (= L. santafeënsis), and Symphysia tubulifera (= L. tubulifera)
Wilson: Connected to Past and Future
Few small cities have attempted—and still fewer have succeeded—in straddling both agricultural and corporate branding. Over the course of the 20th century, and with particular agility in the last two decades, Wilson has managed to attract and retain financial, pharmaceutical and technology-based industries while remaining in the forefront of regional tobacco marketing. While its agricultural connections have perhaps undergone the most drastic changes as a result of a globalized and politically-transformed market, the inroads Wilson has made in strategically pursuing other sectors have been no less remarkable or significant for the city’s economic prospects
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