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https://www.readbyqxmd.com/read/28428010/a-strategy-of-faster-movements-used-by-elderly-humans-to-lift-objects-of-increasing-weight-in-ecological-context
#1
Thomas Hoellinger, Joseph McIntyre, Lena Jami, Sylvain Hanneton, Guy Cheron, Agnes Roby-Brami
It is not known whether, during the course of ageing, changes occur in the motor strategies used by the CNS for lifting objects of different weights. Here, we analysed the kinematics of object-lifting in two different healthy groups (young and elderly people) plus one well known deafferented patient (GL). The task was to reach and lift onto a shelf an opaque cylindrical object with changing weight. The movements of the hand and object were recorded with electromagnetic sensors. In an ecological context (i.e...
April 17, 2017: Neuroscience
https://www.readbyqxmd.com/read/28414802/neuronal-cell-fate-specification-by-the-molecular-convergence-of-different-spatio-temporal-cues-on-a-common-initiator-terminal-selector-gene
#2
Johannes Stratmann, Stefan Thor
The extensive genetic regulatory flows underlying specification of different neuronal subtypes are not well understood at the molecular level. The Nplp1 neuropeptide neurons in the developing Drosophila nerve cord belong to two sub-classes; Tv1 and dAp neurons, generated by two distinct progenitors. Nplp1 neurons are specified by spatial cues; the Hox homeotic network and GATA factor grn, and temporal cues; the hb -> Kr -> Pdm -> cas -> grh temporal cascade. These spatio-temporal cues combine into two distinct codes; one for Tv1 and one for dAp neurons that activate a common terminal selector feedforward cascade of col -> ap/eya -> dimm -> Nplp1...
April 17, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28413823/long-term-predictive-and-feedback-encoding-of-motor-signals-in-the-simple-spike-discharge-of-purkinje-cells
#3
Laurentiu S Popa, Martha L Streng, Timothy J Ebner
Most hypotheses of cerebellar function emphasize a role in real-time control of movements. However, the cerebellum's use of current information to adjust future movements and its involvement in sequencing, working memory, and attention argues for predicting and maintaining information over extended time windows. The present study examines the time course of Purkinje cell discharge modulation in the monkey (Macaca mulatta) during manual, pseudo-random tracking. Analysis of the simple spike firing from 183 Purkinje cells during tracking reveals modulation up to 2 s before and after kinematics and position error...
March 2017: ENeuro
https://www.readbyqxmd.com/read/28398244/piezoelectric-actuated-phase-shifter-based-on-external-laser-interferometer-design-control-and-experimental-validation
#4
Peng-Zhi Li, Xiao-Dong Wang, Yong-Xin Sui, De-Fu Zhang, Dong-Fang Wang, Li-Jian Dong, Ming-Yang Ni
To improve the phase-shifting accuracy, this paper presents a novel integrated framework for design, control and experimental validation of the piezoelectric actuated phase shifter with a trade-off between accuracy and cost. The piezoelectric actuators with built-in sensors are adopted to drive the double parallel four-bar linkage flexure hinge-based mechanisms. Three mechanisms form the tripod structure of the assembled phase shifter. Then, a semi-closed loop controller with inner feedback and outer feedforward loops via the external laser interferometer is developed for accurate positioning of the phase shifter...
April 11, 2017: Sensors
https://www.readbyqxmd.com/read/28392606/design-of-an-embedded-inverse-feedforward-biomolecular-tracking-controller-for-enzymatic-reaction-processes
#5
Mathias Foo, Jongrae Kim, Rucha Sawlekar, Declan G Bates
Feedback control is widely used in chemical engineering to improve the performance and robustness of chemical processes. Feedback controllers require a 'subtractor' that is able to compute the error between the process output and the reference signal. In the case of embedded biomolecular control circuits, subtractors designed using standard chemical reaction network theory can only realise one-sided subtraction, rendering standard controller design approaches inadequate. Here, we show how a biomolecular controller that allows tracking of required changes in the outputs of enzymatic reaction processes can be designed and implemented within the framework of chemical reaction network theory...
April 6, 2017: Computers & Chemical Engineering
https://www.readbyqxmd.com/read/28386448/elasticity-improves-handgrip-performance-and-user-experience-during-visuomotor-control
#6
Michael Mace, Paul Rinne, Jean-Luc Liardon, Catherine Uhomoibhi, Paul Bentley, Etienne Burdet
Passive rehabilitation devices, providing motivation and feedback, potentially offer an automated and low-cost therapy method, and can be used as simple human-machine interfaces. Here, we ask whether there is any advantage for a hand-training device to be elastic, as opposed to rigid, in terms of performance and preference. To address this question, we have developed a highly sensitive and portable digital handgrip, promoting independent and repetitive rehabilitation of grasp function based around a novel elastic force and position sensing structure...
February 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28367561/cancerous-perturbations-within-the-erk-pi3k-akt-and-wnt-%C3%AE-catenin-signaling-network-constitutively-activate-inter-pathway-positive-feedback-loops
#7
Rahul Rao Padala, Rishabh Karnawat, Satish Bharathwaj Viswanathan, Abhishek Vijay Thakkar, Asim Bikas Das
Perturbations in molecular signaling pathways are a result of genetic or epigenetic alterations, which may lead to malignant transformation of cells. Despite cellular robustness, specific genetic or epigenetic changes of any gene can trigger a cascade of failures, which result in the malfunctioning of cell signaling pathways and lead to cancer phenotypes. The extent of cellular robustness has a link with the architecture of the network such as feedback and feedforward loops. Perturbation in components within feedback loops causes a transition from a regulated to a persistently activated state and results in uncontrolled cell growth...
April 3, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28355147/glimpse-google-glass-interface-for-sensory-feedback-in-myoelectric-hand-prostheses
#8
Marko Markovic, Hemanth Karnal, Bernhard Graimann, Dario Farina, Strahinja Dosen
OBJECTIVE: Providing sensory feedback to the user of the prosthesis is an important challenge. The common approach is to use tactile stimulation, which is easy to implement but requires training and has limited information bandwidth. In this study, we propose an alternative approach based on augmented reality. APPROACH: We have developed the GLIMPSE, a Google Glass application which connects to the prosthesis via a Bluetooth interface and renders the prosthesis states (EMG signals, aperture, force and contact) using augmented reality (see-through display) and sound (bone conduction transducer)...
March 29, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28351197/the-human-central-pattern-generator-for-locomotion
#9
Karen Minassian, Ursula S Hofstoetter, Florin Dzeladini, Pierre A Guertin, Auke Ijspeert
The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion...
March 1, 2017: Neuroscientist: a Review Journal Bringing Neurobiology, Neurology and Psychiatry
https://www.readbyqxmd.com/read/28350336/sensor-fault-and-delay-tolerant-control-for-networked-control-systems-subject-to-external-disturbances
#10
Shi-Yuan Han, Yue-Hui Chen, Gong-You Tang
In this paper, the problem of sensor fault and delay tolerant control problem for a class of networked control systems under external disturbances is investigated. More precisely, the dynamic characteristics of the external disturbance and sensor fault are described as the output of exogenous systems first. The original sensor fault and delay tolerant control problem is reformulated as an equivalence problem with designed available system output and reformed performance index. The feedforward and feedback sensor fault tolerant controller (FFSFTC) can be obtained by utilizing the solutions of Riccati matrix equation and Stein matrix equation...
March 28, 2017: Sensors
https://www.readbyqxmd.com/read/28348530/paradigm-shifts-in-voluntary-force-control-and-motor-unit-behaviors-with-the-manipulated-size-of-visual-error-perception
#11
Yi-Ching Chen, Yen-Ting Lin, Gwo-Ching Chang, Ing-Shiou Hwang
The detection of error information is an essential prerequisite of a feedback-based movement. This study investigated the differential behavior and neurophysiological mechanisms of a cyclic force-tracking task using error-reducing and error-enhancing feedback. The discharge patterns of a relatively large number of motor units (MUs) were assessed with custom-designed multi-channel surface electromyography following mathematical decomposition of the experimentally-measured signals. Force characteristics, force-discharge relation, and phase-locking cortical activities in the contralateral motor cortex to individual MUs were contrasted among the low (LSF), normal (NSF), and high scaling factor (HSF) conditions, in which the sizes of online execution errors were displayed with various amplification ratios...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28341164/expectation-violation-and-attention-to-pain-jointly-modulate-neural-gain-in-somatosensory-cortex
#12
Francesca Fardo, Ryszard Auksztulewicz, Micah Allen, Martin J Dietz, Andreas Roepstorff, Karl J Friston
The neural processing and experience of pain are influenced by both expectations and attention. For example, the amplitude of event-related pain responses is enhanced by both novel and unexpected pain, and by moving the focus of attention towards a painful stimulus. Under predictive coding, this congruence can be explained by appeal to a precision-weighting mechanism, which mediates bottom-up and top-down attentional processes by modulating the influence of feedforward and feedback signals throughout the cortical hierarchy...
March 21, 2017: NeuroImage
https://www.readbyqxmd.com/read/28329692/organization-of-functional-long-range-circuits-controlling-the-activity-of-serotonergic-neurons-in-the-dorsal-raphe-nucleus
#13
Li Zhou, Ming-Zhe Liu, Qing Li, Juan Deng, Di Mu, Yan-Gang Sun
Serotonergic neurons play key roles in various biological processes. However, circuit mechanisms underlying tight control of serotonergic neurons remain largely unknown. Here, we systematically investigated the organization of long-range synaptic inputs to serotonergic neurons and GABAergic neurons in the dorsal raphe nucleus (DRN) of mice with a combination of viral tracing, slice electrophysiological, and optogenetic techniques. We found that DRN serotonergic neurons and GABAergic neurons receive largely comparable synaptic inputs from six major upstream brain areas...
March 21, 2017: Cell Reports
https://www.readbyqxmd.com/read/28299643/retention-of-the-first-trial-effect-in-gait-slip-among-community-living-older-adults
#14
Xuan Liu, Tanvi Bhatt, Shuaijie Wang, Feng Yang, Yi-Chung Clive Pai
"First-trial effect" characterizes the rapid adaptive behavior that changes the performance outcome (from fall to non-fall) after merely a single exposure to postural disturbance. The purpose of this study was to investigate how long the first-trial effect could last. Seventy-five (≥ 65 years) community-dwelling older adults, who were protected by an overhead full body harness system, were retested for a single slip 6-12 months after their initial exposure to a single gait-slip. Subjects' body kinematics that was used to compute their proactive (feedforward) and reactive (feedback) control of stability was recorded by an eight-camera motion analysis system...
February 2017: GeroScience
https://www.readbyqxmd.com/read/28283576/glucocorticoid-and-cytokine-crosstalk-feedback-feedforward-and-co-regulatory-interactions-determine-repression-or-resistance
#15
Robert Newton, Suharsh V Shah, Mohammed O Altonsy, Anthony N Gerber
Inflammatory signals induce complex feedback and feedforward systems that allow tight temporal control. Whereas glucocorticoids generally repress inflammatory gene expression, GR recruitment increases expression of negative feedback and feedforward regulators, including DUSP1, IRAK3, NFKBIA, TNFAIP3 or ZFP36. Moreover, GR cooperativity with factors, such as NF-κB, can enhance regulator expression to promote repression. Conversely, MAPKs, which are inhibited by glucocorticoids, limit expression of the transcription factor IRF1, and the host defense gene, CXCL10, through a feedforward control mechanism...
March 10, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28268929/cardiovascular-interactions-assessed-via-conditional-joint-transfer-entropy-in-patients-developing-atrial-fibrillation-after-coronary-artery-bypass-graft-surgery
#16
Vlasta Bari, Marco Ranucci, Andrea Marchi, Beatrice De Maria, Valeria Pistuddi, Alberto Porta
Assigned the universe of knowledge Ω as composed by one target and two exogenous signals, the conditional joint transfer entropy (CJTE), assessing the amount of information jointly transferred from the two sources to the target that can be uniquely linked to one of the two sources, was found useful to study cardiovascular control. We propose the assessment of CJTE from systolic arterial pressure (SAP) and respiration (R) to heart period (HP) conditioned on R (CJTESAP, R→HP|R) along the baroreflex, and from HP and R to SAP conditioned on R (CJTEHP, R→SAP|R) along the feedforward mechanical pathway, in 134 patients undergoing coronary artery bypass graft surgery before (PRE) and after (POST) the induction of general anesthesia...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28257585/increased-response-to-altered-auditory-feedback-in-dyslexia-a-weaker-sensorimotor-magnet-implied-in-the-phonological-deficit
#17
Mark R van den Bunt, Margriet A Groen, Takayuki Ito, Ana A Francisco, Vincent L Gracco, Ken R Pugh, Ludo Verhoeven
Purpose: The purpose of this study was to examine whether developmental dyslexia (DD) is characterized by deficiencies in speech sensory and motor feedforward and feedback mechanisms, which are involved in the modulation of phonological representations. Method: A total of 42 adult native speakers of Dutch (22 adults with DD; 20 participants who were typically reading controls) were asked to produce /bep/ while the first formant (F1) of the /e/ was not altered (baseline), increased (ramp), held at maximal perturbation (hold), and not altered again (after-effect)...
March 1, 2017: Journal of Speech, Language, and Hearing Research: JSLHR
https://www.readbyqxmd.com/read/28239504/a-control-framework-for-anthropomorphic-biped-walking-based-on-stabilizing-feedforward-trajectories
#18
Siavash Rezazadeh, Robert D Gregg
Although dynamic walking methods have had notable successes in control of bipedal robots in the recent years, still most of the humanoid robots rely on quasi-static Zero Moment Point controllers. This work is an attempt to design a highly stable controller for dynamic walking of a human-like model which can be used both for control of humanoid robots and prosthetic legs. The method is based on using time-based trajectories that can induce a highly stable limit cycle to the bipedal robot. The time-based nature of the controller motivates its use to entrain a model of an amputee walking, which can potentially lead to a better coordination of the interaction between the prosthesis and the human...
October 2016: Proceedings of the ASME Dynamic Systems and Control Conference
https://www.readbyqxmd.com/read/28230090/advanced-retarded-differential-equations-in-quantum-photonic-systems
#19
Unai Alvarez-Rodriguez, Armando Perez-Leija, Iñigo L Egusquiza, Markus Gräfe, Mikel Sanz, Lucas Lamata, Alexander Szameit, Enrique Solano
We propose the realization of photonic circuits whose dynamics is governed by advanced-retarded differential equations. Beyond their mathematical interest, these photonic configurations enable the implementation of quantum feedback and feedforward without requiring any intermediate measurement. We show how this protocol can be applied to implement interesting delay effects in the quantum regime, as well as in the classical limit. Our results elucidate the potential of the protocol as a promising route towards integrated quantum control systems on a chip...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28227134/cardiovascular-interactions-assessed-via-conditional-joint-transfer-entropy-in-patients-developing-atrial-fibrillation-after-coronary-artery-bypass-graft-surgery
#20
Vlasta Bari, Marco Ranucci, Andrea Marchi, Beatrice De Maria, Valeria Pistuddi, Alberto Porta, Vlasta Bari, Marco Ranucci, Andrea Marchi, Beatrice De Maria, Valeria Pistuddi, Alberto Porta, Vlasta Bari, Andrea Marchi, Alberto Porta, Valeria Pistuddi, Beatrice De Maria, Marco Ranucci
Assigned the universe of knowledge Ω as composed by one target and two exogenous signals, the conditional joint transfer entropy (CJTE), assessing the amount of information jointly transferred from the two sources to the target that can be uniquely linked to one of the two sources, was found useful to study cardiovascular control. We propose the assessment of CJTE from systolic arterial pressure (SAP) and respiration (R) to heart period (HP) conditioned on R (CJTESAP, R→HP|R) along the baroreflex, and from HP and R to SAP conditioned on R (CJTEHP, R→SAP|R) along the feedforward mechanical pathway, in 134 patients undergoing coronary artery bypass graft surgery before (PRE) and after (POST) the induction of general anesthesia...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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