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https://www.readbyqxmd.com/read/28716400/direct-identification-of-generalized-prandtl-ishlinskii-model-inversion-for-asymmetric-hysteresis-compensation
#1
Young-Rae Ko, Yoonkyu Hwang, Minji Chae, Tae-Hyoung Kim
In this study, we present an identification-based direct construction of the inverse generalized Prandtl-Ishlinskii (P-I) model to facilitate inverse model-based feedforward compensation of asymmetric hysteresis nonlinearities. Compared with the derivation of the inverse model analytically from a generalized P-I model, this direct modeling approach has the following advantages. First, direct inverse model identification is formulated as a nonlinear optimization problem, which is not subject to the constraint condition on the generalized P-I model's threshold and density functions, where this is indispensable for the analytical model inversion procedure...
July 14, 2017: ISA Transactions
https://www.readbyqxmd.com/read/28704632/measuring-memory-and-attention-to-preview-in-motion
#2
Richard J Jagacinski, Gordon M Hammond, Emanuele Rizzi
Objective Use perceptual-motor responses to perturbations to reveal the spatio-temporal detail of memory for the recent past and attention to preview when participants track a winding roadway. Background Memory of the recently passed roadway can be inferred from feedback control models of the participants' manual movement patterns. Similarly, attention to preview of the upcoming roadway can be inferred from feedforward control models of manual movement patterns. Method Perturbation techniques were used to measure these memory and attention functions...
August 2017: Human Factors
https://www.readbyqxmd.com/read/28703352/atpds-over-expression-in-tomato-exposing-unique-patterns-of-carotenoid-self-regulation-and-an-alternative-strategy-for-the-enhancement-of-fruit-carotenoid-content
#3
Ryan P McQuinn, Breanna Wong, James J Giovannoni
The regulation of plant carotenogenesis is an active research area for both biological discovery and practical implementation. In tomato (Solanum lycopersicum) we demonstrate additional bottlenecks exist in the poly-cis-transformation of phytoene to lycopene in the context of ripening-induced PSY1 expression and activity, and reveal phytoene desaturase (PDS), as a target for manipulation toward elevated lycopene content in maturing tomato fruit. Over-expression of Arabidopsis PDS, AtPDS, elevated PDS transcript abundance in all aerial tissues resulting in both altered carotenoid accumulation and associated pathway gene expression in a tissue-specific manner...
July 13, 2017: Plant Biotechnology Journal
https://www.readbyqxmd.com/read/28701537/climbing-fibers-predict-movement-kinematics-and-performance-errors
#4
Martha L Streng, Laurentiu S Popa, Timothy J Ebner
Requisite for understanding cerebellar function is a complete characterization of the signals provided by complex spike (CS) discharge of Purkinje cells, the output neurons of the cerebellar cortex. Numerous studies have provided insights into CS function, with the most predominant view being that they are evoked by error events. However, several reports suggest that CSs encode other aspects of movements and do not always respond to errors or unexpected perturbations. Here, we evaluated CS firing during a pseudo-random manual tracking task in the monkey (Macaca mulatta)...
July 12, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28701534/compensating-for-intersegmental-dynamics-across-the-shoulder-elbow-and-wrist-joints-during-feedforward-and-feedback-control
#5
Rodrigo S Maeda, Tyler Cluff, Paul L Gribble, J Andrew Pruszynski
Moving the arm is complicated by mechanical interactions that arise between limb segments. Such intersegmental dynamics cause torques applied at one joint to produce movement at multiple joints. Here, we investigated whether the nervous system accounts for intersegmental limb dynamics across the shoulder, elbow, and wrist joints during self-initiated planar reaching and when countering external mechanical perturbations. Our first experiment tested whether the timing and amplitude of shoulder muscle activity accounts for interaction torques produced during single-joint elbow movements from different elbow initial orientations and over a range of movement speeds...
July 12, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28690340/run-to-run-optimization-control-within-exact-inverse-framework-for-scan-tracking
#6
Ivan L Yeoh, Per G Reinhall, Martin C Berg, Howard J Chizeck, Eric J Seibel
A run-to-run optimization controller uses a reduced set of measurement parameters, in comparison to more general feedback controllers, to converge to the best control point for a repetitive process. A new run-to-run optimization controller is presented for the scanning fiber device used for image acquisition and display. This controller utilizes very sparse measurements to estimate a system energy measure and updates the input parameterizations iteratively within a feedforward with exact-inversion framework...
September 2017: Journal of Dynamic Systems, Measurement, and Control
https://www.readbyqxmd.com/read/28686594/cannabinoids-disrupt-memory-encoding-by-functionally-isolating-hippocampal-ca1-from-ca3
#7
Roman A Sandler, Dustin Fetterhoff, Robert E Hampson, Sam A Deadwyler, Vasilis Z Marmarelis
Much of the research on cannabinoids (CBs) has focused on their effects at the molecular and synaptic level. However, the effects of CBs on the dynamics of neural circuits remains poorly understood. This study aims to disentangle the effects of CBs on the functional dynamics of the hippocampal Schaffer collateral synapse by using data-driven nonparametric modeling. Multi-unit activity was recorded from rats doing an working memory task in control sessions and under the influence of exogenously administered tetrahydrocannabinol (THC), the primary CB found in marijuana...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28681238/impedance-feedback-control-of-microfluidic-valves-for-reliable-post-processing-combinatorial-droplet-injection
#8
Brant Axt, Yi-Fan Hsieh, Divya Nalayanda, Tza-Huei Wang
Droplet microfluidics has found use in many biological assay applications as a means of high-throughput sample processing. One of the challenges of the technology, however, is the ability to control and merge droplets on-demand as they flow through the microdevices. It is in the interest of developing lab-on-chip devices to be able to combinatorically program additive mixing steps for more complex multistep and multiplex assays. Existing technologies to merge droplets are either passive in nature or require highly predictable droplet movement for feedforward control, making them vulnerable to errors during high throughput operation...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28652413/dopaminergic-modulation-of-synaptic-integration-and-firing-patterns-in-the-rat-entopenduncular-nucleus
#9
Hagar Lavian, Mara Almog, Ravit Madar, Yocheved Loewenstern, Izhar Bar-Gad, Eitan Okun, Alon Korngreen
Dopamine is known to differentially modulate the impact of cortical input to the striatum between the direct and indirect pathways of the basal ganglia (BG). However, the role of extrastriatal dopamine receptors (DRs) in BG information processing is less clear. To investigate the role of extrastriatal DRs we studied their distribution and function in one of the output nuclei of the rodent's BG, the entopeduncular nucleus (EP). qRT-PCR indicated that all DR subtypes were expressed by EP neurons, suggesting that both D1-like receptors (D1LRs) and D2-like receptors (D2LRs) were likely to affect information processing in the EP...
June 26, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28624113/pi-controller-design-for-indirect-vector-controlled-induction-motor-a-decoupling-approach
#10
Jitendra Kr Jain, Sandip Ghosh, Somnath Maity, Pawel Dworak
Decoupling of the stator currents is important for smoother torque response of indirect vector controlled induction motors. Typically, feedforward decoupling is used to take care of current coupling that requires exact knowledge of motor parameters, additional circuitry and signal processing. In this paper, a method is proposed to design the regulating proportional-integral gains that minimize coupling without any requirement of the additional decoupler. The variation of the coupling terms for change in load torque is considered as the performance measure...
June 14, 2017: ISA Transactions
https://www.readbyqxmd.com/read/28617826/cf2-transcription-factor-is-involved-in-the-regulation-of-mef2-rna-levels-nuclei-number-and-muscle-fiber-size
#11
Juan J Arredondo, Jorge Vivar, Sara Laine-Menéndez, Leticia Martínez-Morentin, Margarita Cervera
CF2 and Mef2 influence a variety of developmental muscle processes at distinct stages of development. Nevertheless, the exact nature of the CF2-Mef2 relationship and its effects on muscle building remain yet to be resolved. Here, we explored the regulatory role of CF2 in the Drosophila embryo muscle formation. To address this question and not having proper null CF2 mutants we exploited loss or gain of function strategies to study the contribution of CF2 to Mef2 transcription regulation and to muscle formation...
2017: PloS One
https://www.readbyqxmd.com/read/28611619/hammering-does-not-fit-fitts-law
#12
Tadej Petrič, Cole S Simpson, Aleš Ude, Auke J Ijspeert
While movement is essential to human wellbeing, we are still unable to reproduce the deftness and robustness of human movement in automatons or completely restore function to individuals with many types of motor impairment. To better understand how the human nervous system plans and controls movements, neuromechanists employ simple tasks such as upper extremity reaches and isometric force tasks. However, these simple tasks rarely consider impacts and may not capture aspects of motor control that arise from real-world complexity...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28600254/short-and-long-term-learning-of-feedforward-control-of-a-myoelectric-prosthesis-with-sensory-feedback-by-amputees
#13
Matija Strbac, Milica Isakovic, Minja Belic, Igor Popovic, Igor Simanic, Dario Farina, Thierry Keller, Strahinja Dosen
Human motor control relies on a combination of feedback and feedforward strategies. The aim of this study was to longitudinally investigate artificial somatosensory feedback and feedforward control in the context of grasping with myoelectric prosthesis. Nine amputee subjects performed routine grasping trials, with the aim to produce four levels of force during four blocks of 60 trials across five days. The electrotactile force feedback was provided in the second and third block using multipad electrode and spatial coding...
June 6, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28598717/inhibitory-plasticity-balance-control-and-codependence
#14
Guillaume Hennequin, Everton J Agnes, Tim P Vogels
Inhibitory neurons, although relatively few in number, exert powerful control over brain circuits. They stabilize network activity in the face of strong feedback excitation and actively engage in computations. Recent studies reveal the importance of a precise balance of excitation and inhibition in neural circuits, which often requires exquisite fine-tuning of inhibitory connections. Wereview inhibitory synaptic plasticity and its roles in shaping both feedforward and feedback control. We discuss the necessity of complex, codependent plasticity mechanisms to build nontrivial, functioning networks, and we end by summarizing experimental evidence of such interactions...
June 9, 2017: Annual Review of Neuroscience
https://www.readbyqxmd.com/read/28592697/top-down-beta-enhances-bottom-up-gamma
#15
Craig G Richter, William H Thompson, Conrado A Bosman, Pascal Fries
Several recent studies have demonstrated that the bottom-up signaling of a visual stimulus is subserved by interareal gamma-band synchronization, whereas top-down influences are mediated by alpha-beta band synchronization. These processes may implement top-down control of stimulus processing if top-down and bottom-up mediating rhythms are coupled via cross-frequency interaction. To test this possibility, we investigated Granger-causal influences among awake male macaque primary visual area V1, higher visual area V4 and parietal control area 7a during attentional task performance...
June 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28584110/assessing-regulatory-information-in-developmental-gene-regulatory-networks
#16
Isabelle S Peter, Eric H Davidson
Gene regulatory networks (GRNs) provide a transformation function between the static genomic sequence and the primary spatial specification processes operating development. The regulatory information encompassed in developmental GRNs thus goes far beyond the control of individual genes. We here address regulatory information at different levels of network organization, from single node to subcircuit to large-scale GRNs and discuss how regulatory design features such as network architecture, hierarchical organization, and cis-regulatory logic contribute to the developmental function of network circuits...
June 6, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28580693/changes-in-brain-activity-following-intensive-voice-treatment-in-children-with-cerebral-palsy
#17
Reyhaneh Bakhtiari, Jacqueline Cummine, Alesha Reed, Cynthia M Fox, Brea Chouinard, Ivor Cribben, Carol A Boliek
Eight children (3 females; 8-16 years) with motor speech disorders secondary to cerebral palsy underwent 4 weeks of an intensive neuroplasticity-principled voice treatment protocol, LSVT LOUD(®) , followed by a structured 12-week maintenance program. Children were asked to overtly produce phonation (ah) at conversational loudness, cued-phonation at perceived twice-conversational loudness, a series of single words, and a prosodic imitation task while being scanned using fMRI, immediately pre- and post-treatment and 12 weeks following a maintenance program...
June 5, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28555091/gravity-compensation-and-feedback-of-ground-reaction-forces-for-biped-balance-control
#18
Satoshi Ito, Shingo Nishio, Yuuki Fukumoto, Kojiro Matsushita, Minoru Sasaki
This paper considers the balance control of a biped robot under a constant external force or on a sloped ground. We have proposed a control method with feedback of the ground reaction forces and have realized adaptive posture changes that ensure the stability of the robot. However, fast responses have not been obtained because effective control is achieved by an integral feedback that accompanies a time delay necessary for error accumulation. To improve this response, here, we introduce gravity compensation in a feedforward manner...
2017: Applied Bionics and Biomechanics
https://www.readbyqxmd.com/read/28550423/tactile-feedback-is-an-effective-instrument-for-the-training-of-grasping-with-a-prosthesis-at-low-and-medium-force-levels
#19
Alessandro Marco De Nunzio, Strahinja Dosen, Sabrina Lemling, Marko Markovic, Meike Annika Schweisfurth, Nan Ge, Bernhard Graimann, Deborah Falla, Dario Farina
Grasping is a complex task routinely performed in an anticipatory (feedforward) manner, where sensory feedback is responsible for learning and updating the internal model of grasp dynamics. This study aims at evaluating whether providing a proportional tactile force feedback during the myoelectric control of a prosthesis facilitates learning a stable internal model of the prosthesis force control. Ten able-bodied subjects controlled a sensorized myoelectric prosthesis performing four blocks of consecutive grasps at three levels of target force (30, 50, and 70%), repeatedly closing the fully opened hand...
August 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28539421/sound-making-actions-lead-to-immediate-plastic-changes-of-neuromagnetic-evoked-responses-and-induced-%C3%AE-band-oscillations-during-perception
#20
Bernhard Ross, Masihullah Barat, Takako Fujioka
Auditory and sensorimotor brain areas interact during the action-perception cycle of sound making. Neurophysiological evidence of a feedforward model of the action and its outcome has been associated with attenuation of the N1 wave of auditory evoked responses elicited by self-generated sounds, such as talking and singing or playing a musical instrument. Moreover, neural oscillations at β-band frequencies have been related to predicting the sound outcome after action initiation. We hypothesized that a newly learned action-perception association would immediately modify interpretation of the sound during subsequent listening...
June 14, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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