682,643 research outputs found
Graph analysis of functional brain networks: practical issues in translational neuroscience
The brain can be regarded as a network: a connected system where nodes, or
units, represent different specialized regions and links, or connections,
represent communication pathways. From a functional perspective communication
is coded by temporal dependence between the activities of different brain
areas. In the last decade, the abstract representation of the brain as a graph
has allowed to visualize functional brain networks and describe their
non-trivial topological properties in a compact and objective way. Nowadays,
the use of graph analysis in translational neuroscience has become essential to
quantify brain dysfunctions in terms of aberrant reconfiguration of functional
brain networks. Despite its evident impact, graph analysis of functional brain
networks is not a simple toolbox that can be blindly applied to brain signals.
On the one hand, it requires a know-how of all the methodological steps of the
processing pipeline that manipulates the input brain signals and extract the
functional network properties. On the other hand, a knowledge of the neural
phenomenon under study is required to perform physiological-relevant analysis.
The aim of this review is to provide practical indications to make sense of
brain network analysis and contrast counterproductive attitudes
Microglia-derived microvesicles affect microglia phenotype in glioma
Extracellular-released vesicles (EVs), such as microvesicles (MV) and exosomes (Exo)
provide a new type of inter-cellular communication, directly transferring a ready to use
box of information, consisting of proteins, lipids and nucleic acids. In the nervous
system, EVs participate to neuron-glial cross-talk, a bidirectional communication
important to preserve brain homeostasis and, when dysfunctional, involved in several
CNS diseases. We investigated whether microglia-derived EVs could be used to transfer
a protective phenotype to dysfunctional microglia in the context of a brain tumor.
When MV, isolated from microglia stimulated with LPS/IFNg were brain injected in
glioma-bearing mice, we observed a phenotype switch of tumor associated myeloid
cells (TAMs) and a reduction of tumor size. Our findings indicate that the MV cargo,
which contains upregulated transcripts for several inflammation-related genes, can
transfer information in the brain of glioma bearing mice modifying microglial gene
expression, reducing neuronal death and glioma invasion, thus promoting the recovery
of brain homeostasis
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The Brain-Gut-Microbiome Axis.
Preclinical and clinical studies have shown bidirectional interactions within the brain-gut-microbiome axis. Gut microbes communicate to the central nervous system through at least 3 parallel and interacting channels involving nervous, endocrine, and immune signaling mechanisms. The brain can affect the community structure and function of the gut microbiota through the autonomic nervous system, by modulating regional gut motility, intestinal transit and secretion, and gut permeability, and potentially through the luminal secretion of hormones that directly modulate microbial gene expression. A systems biological model is proposed that posits circular communication loops amid the brain, gut, and gut microbiome, and in which perturbation at any level can propagate dysregulation throughout the circuit. A series of largely preclinical observations implicates alterations in brain-gut-microbiome communication in the pathogenesis and pathophysiology of irritable bowel syndrome, obesity, and several psychiatric and neurologic disorders. Continued research holds the promise of identifying novel therapeutic targets and developing treatment strategies to address some of the most debilitating, costly, and poorly understood diseases
Are there optical communication channels in the brain?
Despite great progress in neuroscience, there are still fundamental
unanswered questions about the brain, including the origin of subjective
experience and consciousness. Some answers might rely on new physical
mechanisms. Given that biophotons have been discovered in the brain, it is
interesting to explore if neurons use photonic communication in addition to the
well-studied electro-chemical signals. Such photonic communication in the brain
would require waveguides. Here we review recent work [S. Kumar, K. Boone, J.
Tuszynski, P. Barclay, and C. Simon, Scientific Reports 6, 36508 (2016)]
suggesting that myelinated axons could serve as photonic waveguides. The light
transmission in the myelinated axon was modeled, taking into account its
realistic imperfections, and experiments were proposed both in-vivo and
in-vitro to test this hypothesis. Potential implications for quantum biology
are discussed.Comment: 13 pages, 5 figures, review of arXiv:1607.02969 for Frontiers in
Bioscience, updated figures, new references on existence of opsins in the
brain and experimental effects of light on neuron
Navigation of brain networks
Understanding the mechanisms of neural communication in large-scale brain
networks remains a major goal in neuroscience. We investigated whether
navigation is a parsimonious routing model for connectomics. Navigating a
network involves progressing to the next node that is closest in distance to a
desired destination. We developed a measure to quantify navigation efficiency
and found that connectomes in a range of mammalian species (human, mouse and
macaque) can be successfully navigated with near-optimal efficiency (>80% of
optimal efficiency for typical connection densities). Rewiring network topology
or repositioning network nodes resulted in 45%-60% reductions in navigation
performance. Specifically, we found that brain networks cannot be progressively
rewired (randomized or clusterized) to result in topologies with significantly
improved navigation performance. Navigation was also found to: i) promote a
resource-efficient distribution of the information traffic load, potentially
relieving communication bottlenecks; and, ii) explain significant variation in
functional connectivity. Unlike prevalently studied communication strategies in
connectomics, navigation does not mandate biologically unrealistic assumptions
about global knowledge of network topology. We conclude that the wiring and
spatial embedding of brain networks is conducive to effective decentralized
communication. Graph-theoretic studies of the connectome should consider
measures of network efficiency and centrality that are consistent with
decentralized models of neural communication
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Participants’ perspectives of feasibility of a novel group treatment for people with cognitive communication difficulties following acquired brain injury
Purpose: To determine whether treatment was acceptable to participants and perceived as beneficial by exploring the experiences of people with cognitive communication difficulties following acquired brain injury who participated in a novel, group, communication, project-based treatment. The purpose of the treatment was to improve participants’ communication skills and quality of life, by focusing group activity towards the production of a project and by incorporating individualised communication goals into group sessions.
Methods: Twenty-one people with acquired brain injury recruited from community settings participated in project-based treatment, which comprised one individual and nine group sessions (of 2-3 people) over six weeks. Structured interviews were conducted post-treatment as part of a broader assessment battery. Interviews were transcribed verbatim and analysed using content analysis to identify codes, categories and themes.
Results: Themes identified from the analysis centred around the treatment experience (general experience; group experience; project experience; working on goals) and benefit of treatment (communicative benefit; other benefits; emotional effects; meeting others; something to do). These themes were consistent with the treatment being perceived as acceptable and having initial efficacy for the participant group.
Conclusion: The qualitative data presented here provide positive feasibility findings (acceptability and initial efficacy) of project-based treatment for people with acquired brain injury. The results
highlight the value of incorporating participants’ views in assessing feasibility in developing novel interventions
Measuring Skilled Migration Rates: The Case of Small States
Recent changes in information and communication technologies have contributed to a dramatic increase in the degree of integration and interdependency of countries, markets, and people. Against this background, one aspect of particular concern for small states is the international movement of people. This paper focuses on this particularly important aspect of globalization, with emphasis on the movement of skilled people and its relationship with country size. In addition to overall skilled migration, it provides evidence that controls for migration age in order to distinguish between those educated in the home country and those educated abroad. The authors discuss the growth implications of the brain drain from small countries and policies that may help control it.age structure; aliens; average emigration; average migration; brain; brain drain; brain gain; Census Bureau; Census data; citizen; citizens; citizenship; communication technologies;
Evidence for Information Processing in the Brain
Many cognitive and neuroscientists attempt to assign biological functions to brain structures. To achieve this end, scientists perform experiments that relate the physical properties of brain structures to organism-level abilities, behaviors, and environmental stimuli. Researchers make use of various measuring instruments and methodological techniques to obtain this kind of relational evidence, ranging from single-unit electrophysiology and optogenetics to whole brain functional MRI. Each experiment is intended to identify brain function. However, seemingly independent of experimental evidence, many cognitive scientists, neuroscientists, and philosophers of science assume that the brain processes information as a scientific fact. In this work we analyze categories of relational evidence and find that although physical features of specific brain areas selectively covary with external stimuli and abilities, and that the brain shows reliable causal organization, there is no direct evidence supporting the claim that information processing is a natural function of the brain. We conclude that the belief in brain information processing adds little to the science of cognitive science and functions primarily as a metaphor for efficient communication of neuroscientific data
A study on temporal segmentation strategies for extracting common spatial patterns for brain computer interfacing
Brain computer interfaces (BCI) create a new approach to human computer communication, allowing the user to control a system simply by performing mental tasks such as motor imagery. This paper proposes and analyses different strategies for time segmentation in extracting common spatial patterns of the brain signals associated to these tasks leading to an improvement of BCI performance
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