The segregation of thalamocortical inputs into eye-specific stripes in the developing cat or monkey visual cortex is prevented by manipulations that perturb or abolish neural activity in the visual ...pathway. Such findings show that proper development of the functional organization of visual cortex is dependent on normal patterns of neural activity. The generalization of this conclusion to other sensory cortices has been questioned by findings that the segregation of thalamocortical afferents into a somatotopic barrel pattern in developing rodent primary somatosensory cortex (S1) is not prevented by activity blockade. We show that a temporary block of N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptors in rat S1 during the critical period for barrel development disrupts the topographic refinement of thalamocortical connectivity and columnar organization. These effects are evident well after the blockade is ineffective and thus may be permanent. Our findings show that neural activity and specifically the activation of postsynaptic cortical neurons has a prominent role in establishing the primary sensory map in S1, as well as the topographic organization of higher order synaptic connections.
The identification of specialized areas in the mammalian neocortex, such as the primary visual or somatosensory cortex, is based on distinctions in architectural and functional features. The extent ...to which certain features that distinguish neocortical areas in rats are prespecified or emerge as a result of epigenetic interactions was investigated. Late embryonic visual cortex transplanted to neonatal somatosensory cortex was later assayed for "barrels," anatomically identified functional units unique to somatosensory cortex, and for boundaries of glycoconjugated molecules associated with barrels. Barrels and boundaries form in transplanted visual cortex and are organized in an array that resembles the pattern in the normal barrelfield. These findings show that different regions of the developing neocortex have similar potentials to differentiate features that distinguish neocortical areas and contribute to their unique functional organizations.
The topographic ordering of retinal connections in the rat superior colliculus emerges during early postnatal life from an initially diffuse projection. Disruption of N-methyl-D-aspartate (NMDA) ...receptor activity in the superior colliculus during this period interferes with map remodeling. In rats chronically treated with NMDA receptor antagonists during the first two postnatal weeks, aberrant axons remain and arborize at topographically incorrect sites. These results indicate that, at a stage preceding visually evoked activity, normal NMDA receptor function is important for the development of an ordered neural map in the mammalian brain.
Individual neurons in the brain send their axons over considerable distances to multiple targets, but the mechanisms governing this process are unresolved. An amenable system for studying axon ...outgrowth, branching, and target selection is the mammalian corticopontine projection. This major connection develops from parent corticospinal axons that have already grown past the pons, by a delayed interstitial budding of collateral branches that then grow directly into their target, the basilar pons. When cocultured with explants of developing cortex in three-dimensional collagen matrices, the basilar pons elicits the formation and directional growth of cortical axon collaterals across the intervening matrix. This effect appears to be target-specific and selectively influences neurons in the appropriate cortical layer. These in vitro findings provide evidence that the basilar pons becomes innervated by controlling at a distance the budding and directed ingrowth of cortical axon collaterals through the release of a diffusible, chemotropic molecule.
We present device and circuit characterization resulting from technology/design co-development to improve the design and manufacture of analog/mixed-signal (AMS) circuits in processors. We introduce ...I D -based MOSFET transconductance measurements and a new measurement of drain saturation margin at realistic analog biasing. We also describe routinely monitored scribe lane replicas of key AMS passives and circuits. Such measurements enable construction and validation of compact models better suited to AMS needs than those historically tailored for logic design.
B.1.1.7 lineage SARS-CoV-2 is more transmissible, leads to greater clinical severity, and results in modest reductions in antibody neutralization. Subgenomic RNA (sgRNA) is produced by discontinuous ...transcription of the SARS-CoV-2 genome. Applying our tool (periscope) to ARTIC Network Oxford Nanopore Technologies genomic sequencing data from 4400 SARS-CoV-2 positive clinical samples, we show that normalised sgRNA is significantly increased in B.1.1.7 (alpha) infections (n = 879). This increase is seen over the previous dominant lineage in the UK, B.1.177 (n = 943), which is independent of genomic reads, E cycle threshold and days since symptom onset at sampling. A noncanonical sgRNA which could represent ORF9b is found in 98.4% of B.1.1.7 SARS-CoV-2 infections compared with only 13.8% of other lineages, with a 16-fold increase in median sgRNA abundance. We demonstrate that ORF9b protein levels are increased 6-fold in B.1.1.7 compared to a B lineage virus in vitro. We hypothesise that increased ORF9b in B.1.1.7 is a direct consequence of a triple nucleotide mutation in nucleocapsid (28280:GAT > CAT, D3L) creating a transcription regulatory-like sequence complementary to a region 3' of the genomic leader. These findings provide a unique insight into the biology of B.1.1.7 and support monitoring of sgRNA profiles to evaluate emerging potential variants of concern.
The Sale of Alcoholic Beverages to Minors Dennis O'Leary; Dennis M. Gorman; Speer, Paul W.
Public health reports (1974),
11/1994, Letnik:
109, Številka:
6
Journal Article
Recenzirano
This study reports the findings of a field trial designed to assess the extent of alcohol sales to minors in one county in northwest New Jersey. Two 19-year-old males were successful in purchasing ...alcoholic beverages in 27 of 46 (58.7 percent) establishments visited. On the following day, 23 of the establishments that sold the alcohol were visited again and, on this occasion, 18 (78.3 percent) sold alcohol to the minor. This study supports the findings from surveys that show that underage drinkers can obtain alcohol with ease. Many community groups are now taking action to rectify this situation, and data of the type reported in this paper can be used to assess the effectiveness of their actions.
The results of recent research indicate that the progeny of proliferating cells in the subventricular zone can differentiate in vitro into neurons and glia after completing their last division in the ...adult brain.
The present study was designed, first, to attempt to replicate the previously derived Goldstein and Linden Minnesota Multiphasic Personality Inventory alcoholic personality subtypes, and second, to ...relate these personality patterns to a multidimensional measure of alcohol usage. Two of the previously obtained profile types were replicated through two independent cluster analytic procedures. These subtypes were defined as psychopathic and neurotic-depressive, respectively. Higher levels of drinking-related impairment were associated with anxiety and depression, while lower levels of impairment were related to psychopathic features among patients hospitalized primarily for alcoholism. However, relatively heterogeneous, distinctive configurations of reported drinking benefits, styles, and consequences were found across the Goldstein-Linden subtypes. Methodological factors potentially contributing to the failure to replicate two of the previously derived subtypes were discussed. The potential therapeutic utility of a multivariate classification of personality functioning and the use of a multidimensional assessment of alcohol usage within alcoholic populations was also discussed.
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