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https://www.readbyqxmd.com/read/29224721/synergistic-processing-of-visual-contours-across-cortical-layers-in-v1-and-v2
#1
Rujia Chen, Feng Wang, Hualou Liang, Wu Li
Visual cortical areas are interconnected via layer-specific feedforward and feedback projections. Such intricate connections are thought to be essential for parsing complex visual images, but the synergy among different layers in different cortical areas remains unclear. By simultaneously mapping neuronal activities across cortical depths in V1 and V2 of behaving monkeys, we identified spatiotemporally dissociable processes for grouping contour fragments and segregating background components. These processes generated and amplified contour signals within specific layers in V1 and V2...
November 17, 2017: Neuron
https://www.readbyqxmd.com/read/29209178/a-three-layer-network-model-of-direction-selective-circuits-in-the-optic-tectum
#2
Fatima Abbas, Marcus A Triplett, Geoffrey J Goodhill, Martin P Meyer
The circuit mechanisms that give rise to direction selectivity in the retina have been studied extensively but how direction selectivity is established in retinorecipient areas of the brain is less well understood. Using functional imaging in larval zebrafish we examine how the direction of motion is encoded by populations of neurons at three layers of the optic tectum; retinal ganglion cell axons (RGCs), a layer of superficial inhibitory interneurons (SINs), and periventricular neurons (PVNs), which constitute the majority of neurons in the tectum...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/29204467/home-energy-management-hem-database-a-list-with-coded-attributes-of-308-devices-commercially-available-in-the-us
#3
Marco Pritoni, Rebecca Ford, Beth Karlin, Angela Sanguinetti
Policymakers worldwide are currently discussing whether to include home energy management (HEM) products in their portfolio of technologies to reduce carbon emissions and improve grid reliability. However, very little data is available about these products. Here we present the results of an extensive review including 308 HEM products available on the US market in 2015-2016. We gathered these data from publicly available sources such as vendor websites, online marketplaces and other vendor documents. A coding guide was developed iteratively during the data collection and utilized to classify the devices...
February 2018: Data in Brief
https://www.readbyqxmd.com/read/29201041/decoding-of-human-movements-based-on-deep-brain-local-field-potentials-using-ensemble-neural-networks
#4
Mohammad S Islam, Khondaker A Mamun, Hai Deng
Decoding neural activities related to voluntary and involuntary movements is fundamental to understanding human brain motor circuits and neuromotor disorders and can lead to the development of neuromotor prosthetic devices for neurorehabilitation. This study explores using recorded deep brain local field potentials (LFPs) for robust movement decoding of Parkinson's disease (PD) and Dystonia patients. The LFP data from voluntary movement activities such as left and right hand index finger clicking were recorded from patients who underwent surgeries for implantation of deep brain stimulation electrodes...
2017: Computational Intelligence and Neuroscience
https://www.readbyqxmd.com/read/29199017/linear-integration-of-erk-activity-predominates-over-persistence-detection-in-fra-1-regulation
#5
Taryn E Gillies, Michael Pargett, Marta Minguet, Alex E Davies, John G Albeck
ERK signaling regulates the expression of target genes, but it is unclear how ERK activity dynamics are interpreted. Here, we investigate this question using simultaneous, live, single-cell imaging of two ERK activity reporters and expression of Fra-1, a target gene controlling epithelial cell identity. We find that Fra-1 is expressed in proportion to the amplitude and duration of ERK activity. In contrast to previous "persistence detector" and "selective filter" models in which Fra-1 expression only occurs when ERK activity persists beyond a threshold duration, our observations demonstrate that the network regulating Fra-1 expression integrates total ERK activity and responds to it linearly...
November 24, 2017: Cell Systems
https://www.readbyqxmd.com/read/29195342/grasping-force-hysteresis-compensation-of-a-piezoelectric-actuated-wire-clamp-with-a-modified-inverse-prandtl-ishlinskii-model
#6
Cunman Liang, Fujun Wang, Yanling Tian, Xingyu Zhao, Dawei Zhang
This paper presents the grasping force hysteresis compensation of a piezoelectric-actuated wire clamp with a modified hysteresis model. Considering dynamic characteristics of the wire clamp, a modified inverse Prandtl-Ishlinskii (MIPI) hysteresis model is developed to improve the hysteresis modeling accuracy. The proposed MIPI model is composed of a P-I model and a dynamic model which are connected in parallel. The proposed hysteresis model has the advantage of high modeling accuracy with a concise identification process, which means the step by step identification is not needed here...
November 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29190326/major-feedforward-thalamic-input-into-layer-4c-of-primary-visual-cortex-in-primate
#7
Virginia Garcia-Marin, Jenna G Kelly, Michael J Hawken
One of the underlying principles of how mammalian circuits are constructed is the relative influence of feedforward to recurrent synaptic drive. It has been dogma in sensory systems that the thalamic feedforward input is relatively weak and that there is a large amplification of the input signal by recurrent feedback. Here we show that in trichromatic primates there is a major feedforward input to layer 4C of primary visual cortex. Using a combination of 3D-electron-microscopy and 3D-confocal imaging of thalamic boutons we found that the average feedforward contribution was about 20% of the total excitatory input in the parvocellular (P) pathway, about 3 times the currently accepted values for primates...
November 28, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/29188025/recent-advances-in-understanding-bile-acid-homeostasis
#8
REVIEW
John Yl Chiang
Bile acids are derived from cholesterol to facilitate intestinal nutrient absorption and biliary secretion of cholesterol. Recent studies have identified bile acids as signaling molecules that activate nuclear farnesoid X receptor (FXR) and membrane G protein-coupled bile acid receptor-1 (Gpbar-1, also known as TGR5) to maintain metabolic homeostasis and protect liver and other tissues and cells from bile acid toxicity. Bile acid homeostasis is regulated by a complex mechanism of feedback and feedforward regulation that is not completely understood...
2017: F1000Research
https://www.readbyqxmd.com/read/29187213/jmjd6-promotes-melanoma-carcinogenesis-through-regulation-of-the-alternative-splicing-of-pak1-a-key-mapk-signaling-component
#9
Xujun Liu, Wenzhe Si, Xinhua Liu, Lin He, Jie Ren, Ziran Yang, Jianguo Yang, Wanjin Li, Shumeng Liu, Fei Pei, Xiaohan Yang, Luyang Sun
BACKGROUND: Melanoma, originated from melanocytes located on the basal membrane of the epithelial tissue, is the most aggressive form of skin cancer that accounts for 75% of skin cancer-related death. Although it is believed that BRAF mutation and the mitogen-activated protein kinase (MAPK) pathway play critical roles in the pathogenesis of melanoma, how the MAPK signaling is regulated in melanoma carcinogenesis is still not fully understood. METHODS: We characterized JMJD6 expression in melanoma tissue array by immunohistochemistry analysis...
November 29, 2017: Molecular Cancer
https://www.readbyqxmd.com/read/29173280/predicting-non-linear-dynamics-by-stable-local-learning-in-a-recurrent-spiking-neural-network
#10
Aditya Gilra, Wulfram Gerstner
The brain needs to predict how the body reacts to motor commands, but how a network of spiking neurons can learn non-linear body dynamics using local, online and stable learning rules is unclear. Here, we present a supervised learning scheme for the feedforward and recurrent connections in a network of heterogeneous spiking neurons. The error in the output is fed back through fixed random connections with a negative gain, causing the network to follow the desired dynamics. The rule for Feedback-based Online Local Learning Of Weights (FOLLOW) is local in the sense that weight changes depend on the presynaptic activity and the error signal projected onto the postsynaptic neuron...
November 27, 2017: ELife
https://www.readbyqxmd.com/read/29164228/emg-driven-forward-dynamics-simulation-to-estimate-in-vivo-joint-contact-forces-during-normal-smooth-and-bouncy-gait
#11
Swithin Razu, Trent M Guess
This study leveraged data from the "Sixth Grand Challenge Competition to Predict in Vivo Knee Loads" to create a full-body musculoskeletal model that incorporates subject specific geometries of the right leg in order to concurrently predict knee contact forces, ligament forces, muscle forces, and ground contact forces. The objectives of this paper are twofold: First, to describe an electromyography (EMG)-driven modeling methodology to predict knee contact forces, and second to validate model predictions by evaluating the model predictions against known values for a patient with an instrumented total knee replacement (TKR) for three distinctly different gait styles (normal, smooth, and bouncy gait)...
November 21, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/29163099/a-computational-analysis-of-neural-mechanisms-underlying-the-maturation-of-multisensory-speech-integration-in-neurotypical-children-and-those-on-the-autism-spectrum
#12
Cristiano Cuppini, Mauro Ursino, Elisa Magosso, Lars A Ross, John J Foxe, Sophie Molholm
Failure to appropriately develop multisensory integration (MSI) of audiovisual speech may affect a child's ability to attain optimal communication. Studies have shown protracted development of MSI into late-childhood and identified deficits in MSI in children with an autism spectrum disorder (ASD). Currently, the neural basis of acquisition of this ability is not well understood. Here, we developed a computational model informed by neurophysiology to analyze possible mechanisms underlying MSI maturation, and its delayed development in ASD...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/29162003/feedforward-approximations-to-dynamic-recurrent-network-architectures
#13
Dylan R Muir
Recurrent neural network architectures can have useful computational properties, with complex temporal dynamics and input-sensitive attractor states. However, evaluation of recurrent dynamic architectures requires solving systems of differential equations, and the number of evaluations required to determine their response to a given input can vary with the input or can be indeterminate altogether in the case of oscillations or instability. In feedforward networks, by contrast, only a single pass through the network is needed to determine the response to a given input...
November 21, 2017: Neural Computation
https://www.readbyqxmd.com/read/29162002/encoding-time-in-feedforward-trajectories-of-a-recurrent-neural-network-model
#14
N F Hardy, Dean V Buonomano
Brain activity evolves through time, creating trajectories of activity that underlie sensorimotor processing, behavior, and learning and memory. Therefore, understanding the temporal nature of neural dynamics is essential to understanding brain function and behavior. In vivo studies have demonstrated that sequential transient activation of neurons can encode time. However, it remains unclear whether these patterns emerge from feedforward network architectures or from recurrent networks and, furthermore, what role network structure plays in timing...
November 21, 2017: Neural Computation
https://www.readbyqxmd.com/read/29140550/lncrna-h19-interacts-with-polypyrimidine-tract-binding-protein-1-to-reprogram-hepatic-lipid-homeostasis
#15
Chune Liu, Zhihong Yang, Jianguo Wu, Li Zhang, Sangmin Lee, Dong-Ju Shin, Melanie Tran, Li Wang
H19 is an imprinted long non-coding RNA abundantly expressed in embryonic liver and repressed after birth. Here we show that H19 serves as a lipid sensor by synergizing with RNA-binding protein PTBP1 to modulate hepatic metabolic homeostasis. H19RNA interacts with PTBP1 to facilitate its association with SREBP1c mRNA and protein, leading to increased stability and nuclear transcriptional activity. H19 and PTBP1 are upregulated by fatty acids in hepatocytes and in diet-induced fatty liver, which further augments lipid accumulation...
November 15, 2017: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
https://www.readbyqxmd.com/read/29139049/feedforward-architectures-driven-by-inhibitory-interactions
#16
Yazan N Billeh, Michael T Schaub
Directed information transmission is paramount for many social, physical, and biological systems. For neural systems, scientists have studied this problem under the paradigm of feedforward networks for decades. In most models of feedforward networks, activity is exclusively driven by excitatory neurons and the wiring patterns between them, while inhibitory neurons play only a stabilizing role for the network dynamics. Motivated by recent experimental discoveries of hippocampal circuitry, cortical circuitry, and the diversity of inhibitory neurons throughout the brain, here we illustrate that one can construct such networks even if the connectivity between the excitatory units in the system remains random...
November 14, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/29129925/the-neural-basis-of-homeostatic-and-anticipatory-thirst
#17
REVIEW
Claire Gizowski, Charles W Bourque
Water intake is one of the most basic physiological responses and is essential to sustain life. The perception of thirst has a critical role in controlling body fluid homeostasis and if neglected or dysregulated can lead to life-threatening pathologies. Clear evidence suggests that the perception of thirst occurs in higher-order centres, such as the anterior cingulate cortex (ACC) and insular cortex (IC), which receive information from midline thalamic relay nuclei. Multiple brain regions, notably circumventricular organs such as the organum vasculosum lamina terminalis (OVLT) and subfornical organ (SFO), monitor changes in blood osmolality, solute load and hormone circulation and are thought to orchestrate appropriate responses to maintain extracellular fluid near ideal set points by engaging the medial thalamic-ACC/IC network...
November 13, 2017: Nature Reviews. Nephrology
https://www.readbyqxmd.com/read/29129638/an-attachment-independent-biochemical-timer-of-the-spindle-assembly-checkpoint
#18
Junbin Qian, Maria Adelaida GarcĂ­a-Gimeno, Monique Beullens, Maria Giulia Manzione, Gerd Van der Hoeven, Juan Carlos Igual, Miguel Heredia, Pascual Sanz, Lendert Gelens, Mathieu Bollen
The spindle assembly checkpoint (SAC) generates a diffusible protein complex that prevents anaphase until all chromosomes are properly attached to spindle microtubules. A key step in SAC initiation is the recruitment of MAD1 to kinetochores, which is generally thought to be governed by the microtubule-kinetochore (MT-KT) attachment status. However, we demonstrate that the recruitment of MAD1 via BUB1, a conserved kinetochore receptor, is not affected by MT-KT interactions in human cells. Instead, BUB1:MAD1 interaction depends on BUB1 phosphorylation, which is controlled by a biochemical timer that integrates counteracting kinase and phosphatase effects on BUB1 into a pulse-generating incoherent feedforward loop...
November 16, 2017: Molecular Cell
https://www.readbyqxmd.com/read/29124504/variable-synaptic-strengths-controls-the-firing-rate-distribution-in-feedforward-neural-networks
#19
Cheng Ly, Gary Marsat
Heterogeneity of firing rate statistics is known to have severe consequences on neural coding. Recent experimental recordings in weakly electric fish indicate that the distribution-width of superficial pyramidal cell firing rates (trial- and time-averaged) in the electrosensory lateral line lobe (ELL) depends on the stimulus, and also that network inputs can mediate changes in the firing rate distribution across the population. We previously developed theoretical methods to understand how two attributes (synaptic and intrinsic heterogeneity) interact and alter the firing rate distribution in a population of integrate-and-fire neurons with random recurrent coupling...
November 10, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/29122591/spiking-and-excitatory-inhibitory-input-dynamics-of-barrel-cells-in-response-to-whisker-deflections-of-varying-velocity-and-angular-direction
#20
Mainak Patel
The spiking of barrel regular-spiking (RS) cells is tuned for both whisker deflection direction and velocity. Velocity tuning arises due to thalamocortical (TC) synchrony (but not spike quantity) varying with deflection velocity, coupled with feedforward inhibition, while direction selectivity is not fully understood, though may be due partly to direction tuning of TC spiking. Data show that as deflection direction deviates from the preferred direction of an RS cell, excitatory input to the RS cell diminishes minimally, but temporally shifts to coincide with the time-lagged inhibitory input...
November 6, 2017: Neuroscience
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