Several challenges to current views of thalamocortical processing are offered here. Glutamatergic pathways in thalamus and cortex are divided into two distinct classes: driver and modulator. We ...suggest that driver inputs are the main conduits of information and that modulator inputs modify how driver inputs are processed. Different driver sources reveal two types of thalamic relays: first order relays receive subcortical driver input (for example, retinal input to the lateral geniculate nucleus), whereas higher order relays (for example, pulvinar) receive driver input from layer 5 of cortex and participate in cortico-thalamo-cortical (or transthalamic) circuits. These transthalamic circuits represent an unappreciated aspect of cortical functioning, which I discuss here. Direct corticocortical connections are often paralleled by transthalamic ones. Furthermore, driver inputs to thalamus, both first and higher order, typically arrive via branching axons, and the transthalamic branch often innervates subcortical motor centers, leading to the suggestion that these inputs to thalamus serve as efference copies.
The role of the thalamus in cortical sensory transmission is well known, but its broader role in cognition is less appreciated. Recent studies have shown thalamic engagement in dynamic regulation of ...cortical activity in attention, executive control, and perceptual decision-making, but the circuit mechanisms underlying such functionality are unknown. Because the thalamus is composed of excitatory neurons that are devoid of local recurrent excitatory connectivity, delineating long-range, input-output connectivity patterns of single thalamic neurons is critical for building functional models. We discuss this need in relation to existing organizational schemes such as core versus matrix and first-order versus higher-order relay nuclei. We propose that a new classification is needed based on thalamocortical motifs, where structure naturally informs function. Overall, our synthesis puts understanding thalamic organization at the forefront of existing research in systems and computational neuroscience, with both basic and translational applications.
Halassa and Sherman highlight the role of the thalamus in cortical function and the lack of knowledge surrounding thalamocortical connectivity at single-cell resolution. They propose thalamocortical motifs as units of organization with potential to inform cognitively relevant functional models.
Multiple Imputation Murray, Jared S.
Statistical science,
05/2018, Letnik:
33, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Multiple imputation is a straightforward method for handling missing data in a principled fashion. This paper presents an overview of multiple imputation, including important theoretical results and ...their practical implications for generating and using multiple imputations. A review of strategies for generating imputations follows, including recent developments in flexible joint modeling and sequential regression/chained equations/fully conditional specification approaches. Finally, we compare and contrast different methods for generating imputations on a range of criteria before identifying promising avenues for future research.
Objective
To determine the risk of spontaneous and medically indicated preterm birth associated with mode of birth in previous term‐born pregnancy.
Design
Retrospective cohort study.
Setting
Two UK ...maternity units.
Population or sample
A total of 16 340 women with first two consecutive singleton births and the first birth at term.
Methods
Retrospective cohort study using routinely collected clinical data.
Main outcome measures
Incidence of spontaneous preterm birth and medically indicated preterm birth at less than 37 weeks of gestation after term birth, in relation to mode of birth in first pregnancy. Subgroup analysis on cervical dilatation at the time of first caesarean birth.
Results
Compared with vaginal birth, emergency caesarean birth at full dilatation was associated with an increase in spontaneous preterm birth (2.3% vaginal birth versus 4.5% full dilatation caesarean; adjusted odds ratio aOR 3.29, 95% CI 2.02–5.13, P < 0.001). Elective caesarean, emergency caesarean at <4 cm dilatation, and emergency caesarean at 4–9 cm dilatation were associated with increased medically indicated preterm birth (0.8% vaginal births versus 1.9% elective caesarean, 3.3% <4 cm caesarean, 1.3% 4–9 cm caesarean; aOR 2.30, 95% CI 1.19–4.15, P = 0.009; aOR 4.68, 95% CI 2.98–7.24, P < 0.001; and aOR 2.43, 95% CI 1.43–4.00, P = 0.001, respectively).
Conclusions
Term caesarean in the first stage of labour or performed prelabour is associated with medically indicated preterm birth. Term caesarean in the second stage of labour is associated with spontaneous preterm birth.
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Caesarean in the second stage of labour is associated with spontaneous preterm birth.
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Caesarean in the second stage of labour is associated with spontaneous preterm birth.
Pyramidal cells in cortical Layers 5 and 6 are the only cells in the cerebral cortex with axons that leave the cortex to influence the thalamus. Layer 6 cells provide modulatory feedback input to all ...thalamic nuclei. Layer 5 cells provide driving input to higher‐order thalamic nuclei and do not innervate first‐order nuclei, which get their driving inputs from subcortical sources. Higher‐order nuclei innervated by Layer 5 cells thus seem to be involved with cortico‐thalamo‐cortical communication. The Layer 5 axons branch to also target additional subcortical structures that mediate interactions with the external environment. These corticofugal pathways represent the only means by which the cortex influences the rest of the neuraxis and thus are essential for proper cortical function and species survival. Here we review current understanding of the corticofugal pathways from Layers 5 and 6 and speculate on their functional contributions to neural processing and behavior.
Pyramidal cells in cortical Layers 5 and 6 are the only cells in the cerebral cortex with axons that leave the cortex to influence the thalamus. Layer 6 cells provide modulatory feedback input to all thalamic nuclei, whereas Layer 5 cells provide driving input to higher‐order thalamic nuclei. Here, we review current understanding of the corticofugal pathways and speculate on their functional contributions to neural processing and behavior.
Considering the global rise of obesity and food-linked cardiovascular diseases, food industries are often challenged to produce low fat or fat-free products. Incorporation of water in the form of ...water-in-oil (W/O) emulsions to replace fat offers a promising strategy to address this research challenge.
This review aims to provide succinct insights into the stabilization of W/O emulsions, focusing on interfacial design using surfactants, biopolymers, particles and/or combinations thereof that have been researched in the last decade. Particular emphasis has been given to particle (Pickering) stabilization of water droplets with bio-derived as well as non-bio-derived particles. In addition, the stabilization of W/O emulsions via viscosity modification is also briefly examined.
Although polyglycerol polyricinoleate (PGPR, E476) is considered as the ‘classic’ surfactant when it comes to stabilization of W/O emulsions, the focal point of current research has recently shifted towards the use of particle stabilizers that allow longer term stabilization against coalescence and Ostwald ripening. In particular, Pickering stabilizers that are derived from natural, biodegradable sources, such as zein, cellulose, lignin, starch and polyphenol crystals (curcumin and quercetin), with or without further modification, have attracted burgeoning attention due to the rising popularity of ‘clean-label’ products amongst consumers. Using such particles, or intelligently combining particles with biopolymers to stabilize high water volume fractions in oil continuous matrices, plus the use of biopolymers to gel the water phase, offer promising new applications in food and allied soft matter manufacturing areas in the future.
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•Development of foods with reduced levels of saturated and total fat is a necessity.•Designing water-in-oil (W/O) emulsions is a promising strategy to incorporate water.•W/O emulsions stabilized by surfactants, biopolymers and/or particles are reviewed.•There is a growing need for emulsifiers that are ‘clean-label’ and biodegradable.•Use of bio-derived Pickering particles is a relatively recent endeavour.
We now know that sensory processing in cortex occurs not only via direct communication between primary to secondary areas, but also via their parallel cortico-thalamo-cortical (i.e.,
-thalamic) ...pathways. Both corticocortical and
-thalamic pathways mainly signal through glutamatergic class 1 (driver) synapses, which have robust and efficient synaptic dynamics suited for the transfer of information such as receptive field properties, suggesting the importance of class 1 synapses in feedforward, hierarchical processing. However, such a parallel arrangement has only been identified in sensory cortical areas: visual, somatosensory, and auditory. To test the generality of
-thalamic pathways, we sought to establish its presence beyond purely sensory cortices to determine whether there is a
-thalamic pathway parallel to the established primary somatosensory (S1) to primary motor (M1) pathway. We used
-synaptic viral tracing, optogenetics in slice preparations, and bouton size analysis in the mouse (both sexes) to document that a circuit exists from layer 5 of S1 through the posterior medial nucleus of the thalamus to M1 with glutamatergic class 1 properties. This represents a hitherto unknown, robust sensorimotor linkage and suggests that the arrangement of parallel direct and
-thalamic corticocortical circuits may be present as a general feature of cortical functioning.
During sensory processing, feedforward pathways carry information such as receptive field properties via glutamatergic class 1 synapses, which have robust and efficient synaptic dynamics. As expected, class 1 synapses subserve the feedforward projection from primary to secondary sensory cortex, but also a route through specific higher-order thalamic nuclei, creating a parallel feedforward
-thalamic pathway. We now extend the concept of cortical areas being connected via parallel, direct, and
-thalamic circuits from purely sensory cortices to a sensorimotor cortical circuit (i.e., primary sensory cortex to primary motor cortex). This suggests a generalized arrangement for corticocortical communication.
The lateral geniculate nucleus and pulvinar are examples of two different types of relay: the former is a first order relay, transmitting information from a subcortical source (retina), while the ...latter is mostly a higher order relay, transmitting information from layer 5 of one cortical area to another cortical area. First and higher order thalamic relays can also be recognized for much of the rest of thalamus, and most of thalamus seems to be comprised of higher order relays. Higher order relays seem especially important to general corticocortical communication, and this challenges and extends the conventional view that such communication is based on direct corticocortical connections.
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