898 results match your criteria long-range connections

Unraveling the mechanisms of surround suppression in early visual processing.

PLoS Comput Biol 2021 Apr 22;17(4):e1008916. Epub 2021 Apr 22.

Courant Institute of Mathematical Sciences, New York University, New York, New York, United States of America.

This paper uses mathematical modeling to study the mechanisms of surround suppression in the primate visual cortex. We present a large-scale neural circuit alistic modeling work are used. The remaining parameters are chosen to produce model outputs that emulate experimentally observed size-tuning curves. Read More

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Deep Learning for Reintegrating Biology.

Integr Comp Biol 2021 Apr 20. Epub 2021 Apr 20.

Department of Electrical and Computer Engineering, University of Southern California, 3740 McClintock Avenue, Los Angeles, California 90089, USA.

The goal of this vision paper is to investigate the possible role that advanced machine learning techniques, especially deep learning, could play in the reintegration of various biological disciplines. To achieve this goal, a series of operational, but admittedly very simplistic, conceptualizations have been introduced: Life has been taken as a multidimensional phenomenon that inhabits three physical dimensions (time, space, and scale) and biological research as establishing connection between different points in the domain of life. Each of these points hence denotes a position in time, space, and scale at which a life phenomenon of interest takes place. Read More

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Mechanisms of synaptic transmission dysregulation in the prefrontal cortex: pathophysiological implications.

Mol Psychiatry 2021 Apr 19. Epub 2021 Apr 19.

Department of Physiology and Biophysics, State University of New York at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, USA.

The prefrontal cortex (PFC) serves as the chief executive officer of the brain, controlling the highest level cognitive and emotional processes. Its local circuits among glutamatergic principal neurons and GABAergic interneurons, as well as its long-range connections with other brain regions, have been functionally linked to specific behaviors, ranging from working memory to reward seeking. The efficacy of synaptic signaling in the PFC network is profundedly influenced by monoaminergic inputs via the activation of dopamine, adrenergic, or serotonin receptors. Read More

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Assessing Different Temporal Scales of Calcium Dynamics in Networks of Beta Cell Populations.

Front Physiol 2021 23;12:612233. Epub 2021 Mar 23.

Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia.

Beta cells within the pancreatic islets of Langerhans respond to stimulation with coherent oscillations of membrane potential and intracellular calcium concentration that presumably drive the pulsatile exocytosis of insulin. Their rhythmic activity is multimodal, resulting from networked feedback interactions of various oscillatory subsystems, such as the glycolytic, mitochondrial, and electrical/calcium components. How these oscillatory modules interact and affect the collective cellular activity, which is a prerequisite for proper hormone release, is incompletely understood. Read More

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Development of Individual Variability in Brain Functional Connectivity and Capability across the Adult Lifespan.

Cereb Cortex 2021 Apr 5. Epub 2021 Apr 5.

Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China.

Individual variability exists in both brain function and behavioral performance. However, changes in individual variability in brain functional connectivity and capability across adult development and aging have not yet been clearly examined. Based on resting-state functional magnetic resonance imaging data from a large cohort of participants (543 adults, aged 18-88 years), brain functional connectivity was analyzed to characterize the spatial distribution and differences in individual variability across the adult lifespan. Read More

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Heritability of brain resilience to perturbation in humans.

Neuroimage 2021 Mar 29;235:118013. Epub 2021 Mar 29.

Berenson-Allen Center for Non-invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215 USA. Electronic address:

Resilience is the capacity of complex systems to persist in the face of external perturbations and retain their functional properties and performance. In the present study, we investigated how individual variations in brain resilience, which might influence response to stress, aging and disease, are influenced by genetics and/or the environment, with potential implications for the implementation of resilience-boosting interventions. Resilience estimates were derived from in silico lesioning of either brain regions or functional connections constituting the connectome of healthy individuals belonging to two different large and unique datasets of twins, specifically: 463 individual twins from the Human Connectome Project and 453 individual twins from the Colorado Longitudinal Twin Study. Read More

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Characterizing changes in network connectivity following chronic head trauma in special forces military personnel: a combined resting-fMRI and DTI study.

Brain Inj 2021 Apr 1:1-9. Epub 2021 Apr 1.

Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.

Background: Soldiers are exposed to significant repetitive head trauma, which may disrupt functional and structural brain connectivity patterns.

Purpose/hypothesis: Integrate resting-state functional MRI (rs-fMRI) and diffusion tensor imaging (DTI) to characterize changes in connectivity biomarkers within Canadian Special Operations Forces (CANSOF), hypothesizing that alterations in architectural organization of cortical hubs may follow chronic repetitive head trauma.

Methods: Fifteen CANSOFs with a history of chronic exposure to sub-concussive head trauma and concussive injuries (1. Read More

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Assessing cerebellar-cortical connectivity using concurrent TMS-EEG: a feasibility study.

J Neurophysiol 2021 Mar 31. Epub 2021 Mar 31.

Deakin University, Australia.

Combined single-pulse transcranial magnetic stimulation (TMS) and electroencephalography (EEG) has been used to probe the features of local networks in the cerebral cortex. Here we investigate whether we can use this approach to explore long-range connections between the cerebellum and cerebral cortex. Ten healthy adults received single-pulse suprathreshold TMS to the cerebellum and an occipital/parietal control site with double-cone and figure-of-eight coils while cerebral activity was recorded. Read More

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Secondary motor cortex: Broadcasting and biasing animal's decisions through long-range circuits.

Int Rev Neurobiol 2021 25;158:443-470. Epub 2020 Dec 25.

Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States. Electronic address:

Medial secondary motor cortex (MOs or M2) constitutes the dorsal aspect of the rodent medial frontal cortex. We previously proposed that the function of MOs is to link antecedent conditions, including sensory stimuli and prior choices, to impending actions. In this review, we focus on the long-range pathways between MOs and other cortical and subcortical regions. Read More

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December 2020

Focal lesions induce large-scale percolation of sleep-like intracerebral activity in awake humans.

Neuroimage 2021 Mar 23;234:117964. Epub 2021 Mar 23.

Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy; IRCCS, Fondazione Don Carlo Gnocchi, Milan 20148, Italy; Azrieli Program in Brain, Mind and Consciousness, Canadian Institute for Advanced Research, Toronto, Canada. Electronic address:

Focal cortical lesions are known to result in large-scale functional alterations involving distant areas; however, little is known about the electrophysiological mechanisms underlying these network effects. Here, we addressed this issue by analysing the short and long distance intracranial effects of controlled structural lesions in humans. The changes in Stereo-Electroencephalographic (SEEG) activity after Radiofrequency-Thermocoagulation (RFTC) recorded in 21 epileptic subjects were assessed with respect to baseline resting wakefulness and sleep activity. Read More

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Proc IEEE Int Conf Acoust Speech Signal Process 2020 May 14;2020:6659-6663. Epub 2020 May 14.

Rutgers, the State University of New Jersey, USA.

Most current speech enhancement models use spectrogram features that require an expensive transformation and result in phase information loss. Previous work has overcome these issues by using convolutional networks to learn the temporal correlations across high-resolution waveforms. These models, however, are limited by memory-intensive dilated convolution and aliasing artifacts from upsampling. Read More

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Statistical mechanics of local force dipole responses in computer glasses.

J Chem Phys 2020 May;152(19):194503

Institute for Theoretical Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.

Soft quasilocalized modes (QLMs) are universally featured by structural glasses quenched from a melt, and are involved in several glassy anomalies such as the low-temperature scaling of their thermal conductivity and specific heat, and sound attenuation at intermediate frequencies. In computer glasses, QLMs may assume the form of harmonic vibrational modes under a narrow set of circumstances; however, direct access to their full distribution over frequency is hindered by hybridizations of QLMs with other low-frequency modes (e.g. Read More

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Analysis of segmentation ontology reveals the similarities and differences in connectivity onto L2/3 neurons in mouse V1.

Sci Rep 2021 Mar 2;11(1):4983. Epub 2021 Mar 2.

Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, 25 Howland Street, London, W1T 4JG, UK.

Quantitatively comparing brain-wide connectivity of different types of neuron is of vital importance in understanding the function of the mammalian cortex. Here we have designed an analytical approach to examine and compare datasets from hierarchical segmentation ontologies, and applied it to long-range presynaptic connectivity onto excitatory and inhibitory neurons, mainly located in layer 2/3 (L2/3), of mouse primary visual cortex (V1). We find that the origins of long-range connections onto these two general cell classes-as well as their proportions-are quite similar, in contrast to the inputs on to a cell type in L6. Read More

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Cell-type-specific recruitment of GABAergic interneurons in the primary somatosensory cortex by long-range inputs.

Cell Rep 2021 Feb;34(8):108774

Unit on Functional Neural Circuits, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address:

Extensive hierarchical yet highly reciprocal interactions among cortical areas are fundamental for information processing. However, connectivity rules governing the specificity of such corticocortical connections, and top-down feedback projections in particular, are poorly understood. We analyze synaptic strength from functionally relevant brain areas to diverse neuronal types in the primary somatosensory cortex (S1). Read More

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February 2021

Supernumerary neurons within the cerebral cortical subplate in autism spectrum disorders.

Brain Res 2021 Jun 16;1760:147350. Epub 2021 Feb 16.

Program in Neuroscience, University of Nevada, Reno, United States. Electronic address:

Autism spectrum disorders (ASDs) involve alterations to cortical connectivity that manifest as reduced coordinated activity between cortical regions. The neurons of the cortical subplate are a major contributor to establishing thalamocortical, corticothalamic and corticocortical long-range connections and only a subset of this cell population survives into adulthood. Previous reports of an indistinct gray-white matter boundary in subjects with ASD suggest that the adjacent subplate may also show organizational abnormalities. Read More

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Brain network motifs are markers of loss and recovery of consciousness.

Sci Rep 2021 Feb 16;11(1):3892. Epub 2021 Feb 16.

School of Physical and Occupational Therapy, McGill University, Montreal, Canada.

Motifs are patterns of inter-connections between nodes of a network, and have been investigated as building blocks of directed networks. This study explored the re-organization of 3-node motifs during loss and recovery of consciousness. Nine healthy subjects underwent a 3-h anesthetic protocol while 128-channel electroencephalography (EEG) was recorded. Read More

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February 2021

From Hyposociability to Hypersociability-The Effects of PSD-95 Deficiency on the Dysfunctional Development of Social Behavior.

Front Behav Neurosci 2021 28;15:618397. Epub 2021 Jan 28.

Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.

Abnormal social behavior, including both hypo- and hypersociability, is often observed in neurodevelopmental disorders such as autism spectrum disorders. However, the mechanisms associated with these two distinct social behavior abnormalities remain unknown. Postsynaptic density protein-95 (PSD-95) is a highly abundant scaffolding protein in the excitatory synapses and an essential regulator of synaptic maturation by binding to NMDA and AMPA receptors. Read More

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January 2021

Lack of redundancy between electrophysiological measures of long-range neuronal communication.

BMC Biol 2021 Feb 8;19(1):24. Epub 2021 Feb 8.

Institute of Applied Physiology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.

Background: Communication between brain areas has been implicated in a wide range of cognitive and emotive functions and is impaired in numerous mental disorders. In rodent models, various metrics have been used to quantify inter-regional neuronal communication. However, in individual studies, typically, only very few measures of coupling are reported and, hence, redundancy across such indicators is implicitly assumed. Read More

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February 2021

The Generation and Modulation of Distinct Gamma Oscillations with Local, Horizontal, and Feedback Connections in the Primary Visual Cortex: A Model Study on Large-Scale Networks.

Neural Plast 2021 18;2021:8874516. Epub 2021 Jan 18.

State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China.

Gamma oscillation (GAMMA) in the local field potential (LFP) is a synchronized activity commonly found in many brain regions, and it has been thought as a functional signature of network connectivity in the brain, which plays important roles in information processing. Studies have shown that the response property of GAMMA is related to neural interaction through local recurrent connections (RC), feed-forward (FF), and feedback (FB) connections. However, the relationship between GAMMA and long-range horizontal connections (HC) in the brain remains unclear. Read More

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January 2021

Coordination of local and long range signaling modulates developmental patterning.

J Theor Biol 2021 May 26;517:110596. Epub 2021 Jan 26.

Department of Mathematics, The Ohio State University, Columbus, OH 43210, United States; Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States. Electronic address:

The development of multicellular organisms relies on correct patterns of cell fates to produce functional tissues in the mature organism. A commonly observed developmental pattern consists of alternating cell fates, where neighboring cells take on distinct cell fates characterized by contrasting gene and protein expression levels, and this cell fate pattern repeats over two or more cells. The patterns produced by these fate decisions are regulated by a small number of highly conserved signaling networks, some of which are mediated by long range diffusible signals and others mediated by local contact-dependent signals. Read More

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Unsupervised Learning Facilitates Neural Coordination Across the Functional Clusters of the Connectome.

Front Robot AI 2020 2;7:40. Epub 2020 Apr 2.

Embodied Cognitive Science Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.

Modeling of complex adaptive systems has revealed a still poorly understood benefit of unsupervised learning: when neural networks are enabled to form an associative memory of a large set of their own attractor configurations, they begin to reorganize their connectivity in a direction that minimizes the coordination constraints posed by the initial network architecture. This self-optimization process has been replicated in various neural network formalisms, but it is still unclear whether it can be applied to biologically more realistic network topologies and scaled up to larger networks. Here we continue our efforts to respond to these challenges by demonstrating the process on the connectome of the widely studied nematode worm . Read More

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Topological Transport of Deconfined Hedgehogs in Magnets.

Phys Rev Lett 2020 Dec;125(26):267201

Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.

We theoretically investigate the dynamics of magnetic hedgehogs, which are three-dimensional topological spin textures that exist in common magnets, focusing on their transport properties and connections to spintronics. We show that fictitious magnetic monopoles carried by hedgehog textures obey a topological conservation law, based on which a hydrodynamic theory is developed. We propose a nonlocal transport measurement in the disordered phase, where the conservation of the hedgehog flow results in a nonlocal signal decaying inversely proportional to the distance. Read More

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December 2020

Epothilones Improve Axonal Growth and Motor Outcomes after Stroke in the Adult Mammalian CNS.

Cell Rep Med 2020 Dec 22;1(9):100159. Epub 2020 Dec 22.

Neurovascular Diseases Laboratory, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany.

Stroke leads to the degeneration of short-range and long-range axonal connections emanating from peri-infarct tissue, but it also induces novel axonal projections. However, this regeneration is hampered by growth-inhibitory properties of peri-infarct tissue and fibrotic scarring. Here, we tested the effects of epothilone B and epothilone D, FDA-approved microtubule-stabilizing drugs that are powerful modulators of axonal growth and scar formation, on neuroplasticity and motor outcomes in a photothrombotic mouse model of cortical stroke. Read More

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December 2020

Comprehensive Estimates of Potential Synaptic Connections in Local Circuits of the Rodent Hippocampal Formation by Axonal-Dendritic Overlap.

J Neurosci 2021 Feb 23;41(8):1665-1683. Epub 2020 Dec 23.

Center for Neural Informatics, Structures, & Plasticity, Krasnow Institute for Advanced Study; and Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia 22030-4444

A quantitative description of the hippocampal formation synaptic architecture is essential for understanding the neural mechanisms of episodic memory. Yet the existing knowledge of connectivity statistics between different neuron types in the rodent hippocampus only captures a mere 5% of this circuitry. We present a systematic pipeline to produce first-approximation estimates for most of the missing information. Read More

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February 2021

Optimization and validation of diffusion MRI-based fiber tracking with neural tracer data as a reference.

Sci Rep 2020 12 18;10(1):21285. Epub 2020 Dec 18.

Neural Computation Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.

Diffusion-weighted magnetic resonance imaging (dMRI) allows non-invasive investigation of whole-brain connectivity, which can reveal the brain's global network architecture and also abnormalities involved in neurological and mental disorders. However, the reliability of connection inferences from dMRI-based fiber tracking is still debated, due to low sensitivity, dominance of false positives, and inaccurate and incomplete reconstruction of long-range connections. Furthermore, parameters of tracking algorithms are typically tuned in a heuristic way, which leaves room for manipulation of an intended result. Read More

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December 2020

Self-assembly of a layered two-dimensional molecularly woven fabric.

Nature 2020 12 16;588(7838):429-435. Epub 2020 Dec 16.

Department of Materials, National Graphene Institute, University of Manchester, Manchester, UK.

Fabrics-materials consisting of layers of woven fibres-are some of the most important materials in everyday life. Previous nanoscale weaves include isotropic crystalline covalent organic frameworks that feature rigid helical strands interlaced in all three dimensions, rather than the two-dimensional layers of flexible woven strands that give conventional textiles their characteristic flexibility, thinness, anisotropic strength and porosity. A supramolecular two-dimensional kagome weave and a single-layer, surface-supported, interwoven two-dimensional polymer have also been reported. Read More

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December 2020

A brain-inspired network architecture for cost-efficient object recognition in shallow hierarchical neural networks.

Neural Netw 2021 Feb 28;134:76-85. Epub 2020 Nov 28.

Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea; Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea. Electronic address:

The brain successfully performs visual object recognition with a limited number of hierarchical networks that are much shallower than artificial deep neural networks (DNNs) that perform similar tasks. Here, we show that long-range horizontal connections (LRCs), often observed in the visual cortex of mammalian species, enable such a cost-efficient visual object recognition in shallow neural networks. Using simulations of a model hierarchical network with convergent feedforward connections and LRCs, we found that the addition of LRCs to the shallow feedforward network significantly enhances the performance of networks for image classification, to a degree that is comparable to much deeper networks. Read More

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February 2021

voltage-sensitive dye imaging of mouse cortical activity with mesoscopic optical tomography.

Neurophotonics 2020 Oct 2;7(4):041402. Epub 2020 Dec 2.

University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States.

Cellular layering is a hallmark of the mammalian neocortex with layer and cell type-specific connections within the cortical mantle and subcortical connections. A key challenge in studying circuit function within the neocortex is to understand the spatial and temporal patterns of information flow between different columns and layers. We aimed to investigate the three-dimensional (3D) layer- and area-specific interactions in mouse cortex . Read More

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October 2020

Importance of self-connections for brain connectivity and spectral connectomics.

Biol Cybern 2020 12 26;114(6):643-651. Epub 2020 Nov 26.

School of Physics, The University of Sydney, Sydney, NSW, 2006, Australia.

Spectral analysis and neural field theory are used to investigate the role of local connections in brain connectivity matrices (CMs) that quantify connectivity between pairs of discretized brain regions. This work investigates how the common procedure of omitting such self-connections (i.e. Read More

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December 2020

"Stay nearby or get checked": A Covid-19 control strategy.

Infect Dis Model 2021 16;6:36-45. Epub 2020 Nov 16.

TU Delft, Delft Institute of Applied Mathematics, Netherlands.

This paper repurposes the classic insight from network theory that long-distance connections drive disease propagation into a strategy for controlling a second wave of Covid-19. We simulate a scenario in which a lockdown is first imposed on a population and then partly lifted while long-range transmission is kept at a minimum. Simulated spreading patterns resemble contemporary distributions of Covid- 19 across EU member states, German and Italian regions, and through New York City, providing some model validation. Read More

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November 2020