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https://www.readbyqxmd.com/read/29164228/emg-driven-forward-dynamics-simulation-to-estimate-in-vivo-joint-contact-forces-during-normal-smooth-and-bouncy-gait
#1
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/29162002/encoding-time-in-feedforward-trajectories-of-a-recurrent-neural-network-model
#2
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/29129925/the-neural-basis-of-homeostatic-and-anticipatory-thirst
#3
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
#4
Junbin Qian, Maria Adelaida García-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
#5
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/29117549/prefrontal-cortex-drives-distinct-projection-neurons-in-the-basolateral-amygdala
#6
Laura M McGarry, Adam G Carter
The prefrontal cortex (PFC) regulates emotional behavior via top-down control of the basolateral amygdala (BLA). However, the influence of PFC inputs on the different projection pathways within the BLA remains largely unexplored. Here, we combine whole-cell recordings and optogenetics to study these cell-type specific connections in mouse BLA. We characterize PFC inputs onto three distinct populations of BLA neurons that project to the PFC, ventral hippocampus, or nucleus accumbens. We find that PFC-evoked synaptic responses are strongest at amygdala-cortical and amygdala-hippocampal neurons and much weaker at amygdala-striatal neurons...
November 7, 2017: Cell Reports
https://www.readbyqxmd.com/read/29028183/non-synaptic-signaling-from-cerebellar-climbing-fibers-modulates-golgi-cell-activity
#7
Angela K Nietz, Jada H Vaden, Luke T Coddington, Linda Overstreet-Wadiche, Jacques I Wadiche
Golgi cells are the principal inhibitory neurons at the input stage of the cerebellum, providing feedforward and feedback inhibition through mossy fiber and parallel fiber synapses. In vivo studies have shown that Golgi cell activity is regulated by climbing fiber stimulation, yet there is little functional or anatomical evidence for synapses between climbing fibers and Golgi cells. Here, we show that glutamate released from climbing fibers activates ionotropic and metabotropic receptors on Golgi cells through spillover-mediated transmission...
October 13, 2017: ELife
https://www.readbyqxmd.com/read/29025427/adaptive-hybrid-robotic-system-for-rehabilitation-of-reaching-movement-after-a-brain-injury-a-usability-study
#8
F Resquín, J Gonzalez-Vargas, J Ibáñez, F Brunetti, I Dimbwadyo, L Carrasco, S Alves, C Gonzalez-Alted, A Gomez-Blanco, J L Pons
BACKGROUND: Brain injury survivors often present upper-limb motor impairment affecting the execution of functional activities such as reaching. A currently active research line seeking to maximize upper-limb motor recovery after a brain injury, deals with the combined use of functional electrical stimulation (FES) and mechanical supporting devices, in what has been previously termed hybrid robotic systems. This study evaluates from the technical and clinical perspectives the usability of an integrated hybrid robotic system for the rehabilitation of upper-limb reaching movements after a brain lesion affecting the motor function...
October 12, 2017: Journal of Neuroengineering and Rehabilitation
https://www.readbyqxmd.com/read/28991792/automatic-control-of-the-effluent-turbidity-from-a-chemically-enhanced-primary-treatment-with-microsieving
#9
J Väänänen, S Memet, T Günther, M Lilja, M Cimbritz, J la Cour Jansen
For chemically enhanced primary treatment (CEPT) with microsieving, a feedback proportional integral controller combined with a feedforward compensator was used in large pilot scale to control effluent water turbidity to desired set points. The effluent water turbidity from the microsieve was maintained at various set points in the range 12-80 NTU basically independent for a number of studied variations in influent flow rate and influent wastewater compositions. Effluent turbidity was highly correlated with effluent chemical oxygen demand (COD)...
October 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28985154/rate-of-torque-development-and-feedforward-control-of-the-hip-and-knee-extensors-gender-differences
#10
Kristen M Stearns-Reider, Christopher M Powers
The purpose of this study was to determine whether women demonstrate decreased rate of torque development (RTD) of the hip and knee extensors and altered onset timing of the vastus lateralis and gluteus maximus during a drop-jump task when compared with men. On average, women demonstrated significantly lower normalized RTD of the hip extensors (women: 11.6 ± 1.3 MVT.s(-1), men: 13.1 ± 0.9 MVT.s(-1); p ≤ .01); however, there was no significant difference in knee extensor RTD. Women also demonstrated significantly earlier activation of their vastus lateralis (women: 206...
October 6, 2017: Journal of Motor Behavior
https://www.readbyqxmd.com/read/28981882/electroconvulsive-therapy-selectively-enhanced-feedforward-connectivity-from-fusiform-face-area-to-amygdala-in-major-depressive-disorder
#11
Jiaojian Wang, Qiang Wei, Tongjian Bai, Xiaoqin Zhou, Hui Sun, Benjamin Becker, Yanghua Tian, Kai Wang, Keith Kendrick
Electroconvulsive therapy (ECT) has been widely used to treat the major depressive disorder (MDD), especially for treatment resistant depression. However, the neuroanatomical basis of ECT remains an open problem. In our study, we combined the voxel-based morphology (VBM), resting-state functional connectivity (RSFC), and granger causality analysis (GCA) to identify the longitudinal changes of structure and function in 23 MDD patients before and after ECT. In addition, multivariate pattern analysis using linear support vector machine (SVM) was applied to classify 23 depressed patients from 25 gender, age, and education matched healthy controls...
August 28, 2017: Social Cognitive and Affective Neuroscience
https://www.readbyqxmd.com/read/28974011/a-novel-position-compensation-scheme-for-cable-pulley-mechanisms-used-in-laparoscopic-surgical-robots
#12
Yunlei Liang, Zhijiang Du, Weidong Wang, Lining Sun
The tendon driven mechanism using a cable and pulley to transmit power is adopted by many surgical robots. However, backlash hysteresis objectively exists in cable-pulley mechanisms, and this nonlinear problem is a great challenge in precise position control during the surgical procedure. Previous studies mainly focused on the transmission characteristics of the cable-driven system and constructed transmission models under particular assumptions to solve nonlinear problems. However, these approaches are limited because the modeling process is complex and the transmission models lack general applicability...
September 30, 2017: Sensors
https://www.readbyqxmd.com/read/28961117/high-frequency-ssvep-bci-with-hardware-stimuli-control-and-phase-synchronized-comb-filter
#13
Anna Chabuda, Piotr Durka, Jaroslaw Zygierewicz
We present an efficient implementation of braincomputer interface (BCI) based on high-frequency steady state visually evoked potentials (SSVEP). Individual shape of the SSVEP response is extracted by means of a feedforward comb filter, which adds delayed versions of the signal to itself. Rendering of the stimuli is controlled by specialized hardware (BCI Appliance). Out of 15 participants of the study, 9 were able to produce stable response in at least 8 out of 10 frequencies from the 30-39 Hz range. They achieved on average 96±4% accuracy and 47±5 bit/min information transfer rate (ITR) for an optimized simple 7-letter speller, while generic full-alphabet speller allowed in this group for 89±9% accuracy and 36±9 bit/min ITR...
September 28, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28959971/axonal-synapse-sorting-in-medial-entorhinal-cortex
#14
Helene Schmidt, Anjali Gour, Jakob Straehle, Kevin M Boergens, Michael Brecht, Moritz Helmstaedter
Research on neuronal connectivity in the cerebral cortex has focused on the existence and strength of synapses between neurons, and their location on the cell bodies and dendrites of postsynaptic neurons. The synaptic architecture of individual presynaptic axonal trees, however, remains largely unknown. Here we used dense reconstructions from three-dimensional electron microscopy in rats to study the synaptic organization of local presynaptic axons in layer 2 of the medial entorhinal cortex, the site of grid-like spatial representations...
September 28, 2017: Nature
https://www.readbyqxmd.com/read/28955272/recurrent-convolutional-neural-networks-a-better-model-of-biological-object-recognition
#15
Courtney J Spoerer, Patrick McClure, Nikolaus Kriegeskorte
Feedforward neural networks provide the dominant model of how the brain performs visual object recognition. However, these networks lack the lateral and feedback connections, and the resulting recurrent neuronal dynamics, of the ventral visual pathway in the human and non-human primate brain. Here we investigate recurrent convolutional neural networks with bottom-up (B), lateral (L), and top-down (T) connections. Combining these types of connections yields four architectures (B, BT, BL, and BLT), which we systematically test and compare...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/28943258/adaptation-of-feedforward-movement-control-is-abnormal-in-patients-with-cervical-dystonia-and-tremor
#16
Laura Avanzino, Andrea Ravaschio, Giovanna Lagravinese, Gaia Bonassi, Giovanni Abbruzzese, Elisa Pelosin
OBJECTIVE: It is under debate whether the cerebellum plays a role in dystonia pathophysiology and in the expression of clinical phenotypes. We investigated a typical cerebellar function (anticipatory movement control) in patients with cervical dystonia (CD) with and without tremor. METHODS: Twenty patients with CD, with and without tremor, and 17 healthy controls were required to catch balls of different load: 15 trials with a light ball, 25 trials with a heavy ball (adaptation) and 15 trials with a light ball (post-adaptation)...
September 9, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28939650/muscle-sympathetic-nerve-responses-to-passive-and-active-one-legged-cycling-insight-into-the-contributions-of-central-command
#17
Connor J Doherty, Anthony V Incognito, Karambir Notay, Matthew J Burns, Joshua T Slysz, Jeremy D Seed, Massimo Nardone, Jamie F Burr, Philip J Millar
The contribution of central command to the peripheral vasoconstrictor response during exercise has been investigated using primarily handgrip exercise. The purpose of the present study was to compare muscle sympathetic nerve activity (MSNA) responses during passive (involuntary) and active (voluntary) zeroload cycling to gain insight into the effects of central command on sympathetic outflow during dynamic exercise. Hemodynamic measurements and contralateral leg MSNA (microneurography) were collected in eighteen young healthy participants at rest and during 2 minutes of passive and active zeroload one-legged cycling...
September 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28916520/rubrocerebellar-feedback-loop-isolates-the-interposed-nucleus-as-an-independent-processor-of-corollary-discharge-information-in-mice
#18
Christy S Beitzel, Brenda D Houck, Samantha M Lewis, Abigail L Person
Understanding cerebellar contributions to motor coordination requires deeper insight into how the output structures of the cerebellum, the cerebellar nuclei, integrate their inputs and influence downstream motor pathways. The magnocellular red nucleus (RNm), a brainstem premotor structure, is a major target of the interposed nucleus (IN), and has also been described in previous studies to send feedback collaterals to the cerebellum. Because such a pathway is in a key position to provide motor efferent information to the cerebellum, satisfying predictions about the use of corollary discharge in cerebellar computations, we studied it in mice of both sexes...
October 18, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28901195/feedforward-coordinate-control-of-a-robotic-cell-injection-catheter
#19
Weyland Cheng, Peter K Law
Remote and robotically actuated catheters are the stepping-stones toward autonomous catheters, where complex intravascular procedures may be performed with minimal intervention from a physician. This article proposes a concept for the positional, feedforward control of a robotically actuated cell injection catheter used for the injection of myogenic or undifferentiated stem cells into the myocardial infarct boundary zones of the left ventricle. The prototype for the catheter system was built upon a needle-based catheter with a single degree of deflection, a 3-D printed handle combined with actuators, and the Arduino microcontroller platform...
August 2017: Cell Transplantation
https://www.readbyqxmd.com/read/28895002/synaptic-convergence-regulates-synchronization-dependent-spike-transfer-in-feedforward-neural-networks
#20
Pachaya Sailamul, Jaeson Jang, Se-Bum Paik
Correlated neural activities such as synchronizations can significantly alter the characteristics of spike transfer between neural layers. However, it is not clear how this synchronization-dependent spike transfer can be affected by the structure of convergent feedforward wiring. To address this question, we implemented computer simulations of model neural networks: a source and a target layer connected with different types of convergent wiring rules. In the Gaussian-Gaussian (GG) model, both the connection probability and the strength are given as Gaussian distribution as a function of spatial distance...
September 12, 2017: Journal of Computational Neuroscience
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