625 research outputs found
The quality of English-language websites offering falls-prevention advice to older members of the public and their families
Neuronal circuitry for pain processing in the dorsal horn
Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region
A putative relay circuit providing low-threshold mechanoreceptive input to lamina I projection neurons via vertical cells in lamina II of the rat dorsal horn
Background:
Lamina I projection neurons respond to painful stimuli, and some are also activated by touch or hair movement. Neuropathic pain resulting from peripheral nerve damage is often associated with tactile allodynia (touch-evoked pain), and this may result from increased responsiveness of lamina I projection neurons to non-noxious mechanical stimuli. It is thought that polysynaptic pathways involving excitatory interneurons can transmit tactile inputs to lamina I projection neurons, but that these are normally suppressed by inhibitory interneurons. Vertical cells in lamina II provide a potential route through which tactile stimuli can activate lamina I projection neurons, since their dendrites extend into the region where tactile afferents terminate, while their axons can innervate the projection cells. The aim of this study was to determine whether vertical cell dendrites were contacted by the central terminals of low-threshold mechanoreceptive primary afferents.
Results:
We initially demonstrated contacts between dendritic spines of vertical cells that had been recorded in spinal cord slices and axonal boutons containing the vesicular glutamate transporter 1 (VGLUT1), which is expressed by myelinated low-threshold mechanoreceptive afferents. To confirm that the VGLUT1 boutons included primary afferents, we then examined vertical cells recorded in rats that had received injections of cholera toxin B subunit (CTb) into the sciatic nerve. We found that over half of the VGLUT1 boutons contacting the vertical cells were CTb-immunoreactive, indicating that they were of primary afferent origin.
Conclusions:
These results show that vertical cell dendritic spines are frequently contacted by the central terminals of myelinated low-threshold mechanoreceptive afferents. Since dendritic spines are associated with excitatory synapses, it is likely that most of these contacts were synaptic. Vertical cells in lamina II are therefore a potential route through which tactile afferents can activate lamina I projection neurons, and this pathway could play a role in tactile allodynia
Transport through a strongly coupled graphene quantum dot in perpendicular magnetic field
We present transport measurements on a strongly coupled graphene quantum dot
in a perpendicular magnetic field. The device consists of an etched
single-layer graphene flake with two narrow constrictions separating a 140 nm
diameter island from source and drain graphene contacts. Lateral graphene gates
are used to electrostatically tune the device. Measurements of Coulomb
resonances, including constriction resonances and Coulomb diamonds prove the
functionality of the graphene quantum dot with a charging energy of around 4.5
meV. We show the evolution of Coulomb resonances as a function of perpendicular
magnetic field, which provides indications of the formation of the graphene
specific 0th Landau level. Finally, we demonstrate that the complex pattern
superimposing the quantum dot energy spectra is due to the formation of
additional localized states with increasing magnetic field.Comment: 6 pages, 4 figure
Achimota Pararubulavirus 3: A New Bat-Derived Paramyxovirus of the Genus Pararubulavirus
Bats are an important source of viral zoonoses, including paramyxoviruses. The paramyxoviral Pararubulavirus genus contains viruses mostly derived from bats that are common, diverse, distributed throughout the Old World, and known to be zoonotic. Here, we describe a new member of the genus Achimota pararubulavirus 3 (AchPV3) and its isolation from the urine of African straw-coloured fruit bats on primary bat kidneys cells. We sequenced and analysed the genome of AchPV3 relative to other Paramyxoviridae, revealing it to be similar to known pararubulaviruses. Phylogenetic analysis of AchPV3 revealed the failure of molecular detection in the urine sample from which AchPV3 was derived and an attachment protein most closely related with AchPV2—a pararubulavirus known to cause cross-species transmission. Together these findings add to the picture of pararubulaviruses, their sources, and variable zoonotic potential, which is key to our understanding of host restriction and spillover of bat-derived paramyxoviruses. AchPV3 represents a novel candidate zoonosis and an important tool for further study
Neural correlates of enhanced visual short-term memory for angry faces: An fMRI study
Copyright: © 2008 Jackson et al.Background: Fluid and effective social communication requires that both face identity and emotional expression information are encoded and maintained in visual short-term memory (VSTM) to enable a coherent, ongoing picture of the world and its players. This appears to be of particular evolutionary importance when confronted with potentially threatening displays of emotion - previous research has shown better VSTM for angry versus happy or neutral face identities.Methodology/Principal Findings: Using functional magnetic resonance imaging, here we investigated the neural correlates of this angry face benefit in VSTM. Participants were shown between one and four to-be-remembered angry, happy, or neutral faces, and after a short retention delay they stated whether a single probe face had been present or not in the previous display. All faces in any one display expressed the same emotion, and the task required memory for face identity. We find enhanced VSTM for angry face identities and describe the right hemisphere brain network underpinning this effect, which involves the globus pallidus, superior temporal sulcus, and frontal lobe. Increased activity in the globus pallidus was significantly correlated with the angry benefit in VSTM. Areas modulated by emotion were distinct from those modulated by memory load.Conclusions/Significance: Our results provide evidence for a key role of the basal ganglia as an interface between emotion and cognition, supported by a frontal, temporal, and occipital network.The authors were supported by a Wellcome Trust grant (grant number 077185/Z/05/Z) and by BBSRC (UK) grant BBS/B/16178
Why Do Species Co-Occur? A Test of Alternative Hypotheses Describing Abiotic Differences in Sympatry versus Allopatry Using Spadefoot Toads
Areas of co-occurrence between two species (sympatry) are often thought to arise in regions where abiotic conditions are conducive to both species and are therefore intermediate between regions where either species occurs alone (allopatry). Depending on historical factors or interactions between species, however, sympatry might not differ from allopatry, or, alternatively, sympatry might actually be more extreme in abiotic conditions relative to allopatry. Here, we evaluate these three hypothesized patterns for how sympatry compares to allopatry in abiotic conditions. We use two species of congeneric spadefoot toads, Spea multiplicata and S. bombifrons, as our study system. To test these hypotheses, we created ecological niche models (specifically using Maxent) for both species to create a map of the joint probability of occurrence of both species. Using the results of these models, we identified three types of locations: two where either species was predicted to occur alone (i.e., allopatry for S. multiplicata and allopatry for S. bombifrons) and one where both species were predicted to co-occur (i.e., sympatry). We then compared the abiotic environment between these three location types and found that sympatry was significantly hotter and drier than the allopatric regions. Thus, sympatry was not intermediate between the alternative allopatric sites. Instead, sympatry occurred at one extreme of the conditions occupied by both species. We hypothesize that biotic interactions in these extreme environments facilitate co-occurrence. Specifically, hybridization between S. bombifrons females and S. multiplicata males may facilitate co-occurrence by decreasing development time of tadpoles. Additionally, the presence of alternative food resources in more extreme conditions may preclude competitive exclusion of one species by the other. This work has implications for predicting how interacting species will respond to climate change, because species interactions may facilitate survival in extreme habitats
The inner centromere is a biomolecular condensate scaffolded by the chromosomal passenger complex.
The inner centromere is a region on every mitotic chromosome that enables specific biochemical reactions that underlie properties, such as the maintenance of cohesion, the regulation of kinetochores and the assembly of specialized chromatin, that can resist microtubule pulling forces. The chromosomal passenger complex (CPC) is abundantly localized to the inner centromeres and it is unclear whether it is involved in non-kinase activities that contribute to the generation of these unique chromatin properties. We find that the borealin subunit of the CPC drives phase separation of the CPC in vitro at concentrations that are below those found on the inner centromere. We also provide strong evidence that the CPC exists in a phase-separated state at the inner centromere. CPC phase separation is required for its inner-centromere localization and function during mitosis. We suggest that the CPC combines phase separation, kinase and histone code-reading activities to enable the formation of a chromatin body with unique biochemical activities at the inner centromere
The scientific basis of climate-smart agriculture: A systematic review protocol
Background: ‘Climate-smart agriculture’ (CSA)—agriculture and food systems that
sustainably increase food production, improve resilience (or adaptive capacity) of farming
systems, and mitigate climate change when possible—has quickly been integrated into the
global development agenda. However, the empirical evidence base for CSA has not been
assembled, complicating the transition from CSA concept to concrete actions, and
contributing to ideological disagreement among development practitioners. Thus, there is an
urgent need to evaluate current knowledge on the effectiveness of CSA to achieve its intended
benefits and inform discourse on food, agriculture, and climate change. This systematic
review intends to establish the scientific evidence base of CSA practices to inform the next
steps in development of agricultural programming and policy. We will evaluate the impact of
73 promising farm-level management practices across five categories (agronomy,
agroforestry, livestock, postharvest management, and energy systems) to assess their
contributions to the three CSA pillars: (1) agronomic and economic productivity, (2)
resilience and adaptive capacity, and (3) climate change mitigation in the developing world.
The resulting data will be compiled into a searchable Web-based database and analytical
engine that can be used to assess the relative effectiveness and strength of evidence for CSA,
as well as identify best-fit practices for specific farming and development contexts. This
represents the largest meta-analysis of agricultural practices to date.
Methods/Design: This protocol sets out the approach for investigating the question: How do
farm-level CSA management practices and technologies affect food production and/or
farmers’ incomes, resilience/adaptive capacity, and climate change mitigation in farming
systems of developing countries? The objective of this ongoing systematic review is to
provide a first appraisal of the evidence for CSA practices in order to inform subsequent
programming. The review is based on data found in English-language peer-reviewed journals
with searches using terms relevant to CSA practices and CSA outcomes. Searches were
conducted via Web of Science (WoS) and Scopus. Articles located were screened first by
abstract and then full text according to predefined eligibility criteria for inclusion in the
review. Data capturing the context of the study (e.g., geographic location, environmental
context), management practices, and impacts (e.g., indicators of CSA outcomes) will be
compiled from those studies that meet the predetermined criteria. Statistical relationships
between practices and impacts will be evaluated via meta-analytical approaches including
response ratios and effect sizes. Mechanisms to identify bias and maintain consistency
continue to be applied throughout the review process. These analyses will be complemented
with an analysis of determinants of/barriers to adoption of promising CSA practices covered
in the meta-analysis. Results of the review will be incorporated into a publicly available Web-based
database. Data will be publicly available under Creative Commons License in 2016
Synaptic Connections of the Neurokinin 1 Receptor-Like Immunoreactive Neurons in the Rat Medullary Dorsal Horn
The synaptic connections between neurokinin 1 (NK1) receptor-like immunoreactive (LI) neurons and γ-aminobutyric acid (GABA)-, glycine (Gly)-, serotonin (5-HT)- or dopamine-β-hydroxylase (DBH, a specific marker for norepinephrinergic neuronal structures)-LI axon terminals in the rat medullary dorsal horn (MDH) were examined under electron microscope by using a pre-embedding immunohistochemical double-staining technique. NK1 receptor-LI neurons were observed principally in laminae I and III, only a few of them were found in lamina II of the MDH. GABA-, Gly-, 5-HT-, or DBH-LI axon terminals were densely encountered in laminae I and II, and sparsely in lamina III of the MDH. Some of these GABA-, Gly-, 5-HT-, or DBH-LI axon terminals were observed to make principally symmetric synapses with NK1 receptor-LI neuronal cell bodies and dendritic processes in laminae I, II and III of the MDH. The present results suggest that neurons expressing NK1 receptor within the MDH might be modulated by GABAergic and glycinergic inhibitory intrinsic neurons located in the MDH and 5-HT- or norepinephrine (NE)-containing descending fibers originated from structures in the brainstem
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