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https://www.readbyqxmd.com/read/28230090/advanced-retarded-differential-equations-in-quantum-photonic-systems
#1
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
#2
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
https://www.readbyqxmd.com/read/28218241/massively-augmented-hippocampal-dentate-granule-cell-activation-accompanies-epilepsy-development
#3
Christopher G Dengler, Cuiyong Yue, Hajime Takano, Douglas A Coulter
In a mouse model of temporal lobe epilepsy, multicellular calcium imaging revealed that disease emergence was accompanied by massive amplification in the normally sparse, afferent stimulation-induced activation of hippocampal dentate granule cells. Patch recordings demonstrated reductions in local inhibitory function within the dentate gyrus at time points where sparse activation was compromised. Mimicking changes in inhibitory synaptic function and transmembrane chloride regulation was sufficient to elicit the dentate gyrus circuit collapse evident during epilepsy development...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28167793/theory-of-cortical-function
#4
David J Heeger
Most models of sensory processing in the brain have a feedforward architecture in which each stage comprises simple linear filtering operations and nonlinearities. Models of this form have been used to explain a wide range of neurophysiological and psychophysical data, and many recent successes in artificial intelligence (with deep convolutional neural nets) are based on this architecture. However, neocortex is not a feedforward architecture. This paper proposes a first step toward an alternative computational framework in which neural activity in each brain area depends on a combination of feedforward drive (bottom-up from the previous processing stage), feedback drive (top-down context from the next stage), and prior drive (expectation)...
February 6, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28158187/correction-when-optimal-feedback-control-is-not-enough-feedforward-strategies-are-required-for-optimal-control-with-active-sensing
#5
(no author information available yet)
[This corrects the article DOI: 10.1371/journal.pcbi.1005190.].
February 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28149391/spatial-control-of-reflexes-posture-and-movement-in-normal-conditions-and-after-neurological-lesions
#6
Anatol G Feldman, Mindy F Levin
Control of reflexes is usually associated with central modulation of their sensitivity (gain) or phase-dependent inhibition and facilitation of their influences on motoneurons (reflex gating). Accumulated empirical findings show that the gain modulation and reflex gating are secondary, emergent properties of central control of spatial thresholds at which reflexes become functional. In this way, the system pre-determines, in a feedforward and task-specific way, where, in a spatial domain or a frame of reference, muscles are allowed to work without directly prescribing EMG activity and forces...
September 1, 2016: Journal of Human Kinetics
https://www.readbyqxmd.com/read/28147609/time-domain-versus-frequency-domain-effort-weighting-in-active-noise-control-design
#7
Emmanuel Friot
Active noise control is often designed by minimizing an error index which includes a penalty on the actuator inputs. In this way, an effort-weighting parameter allows one to monitor the maximum voltages applied to the control sources. Two effort-weighting techniques have been widely implemented in previous studies, Tikhonov regularization for frequency-domain simulations and the leaky filtered-reference least mean square algorithm for real-time feedforward control. This paper introduces the formal connection between the weighting parameters of these two techniques...
January 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28141541/the-roles-of-feedback-and-feedforward-as-humans-learn-to-control-unknown-dynamic-systems
#8
Xingye Zhang, Shaoqian Wang, Jesse B Hoagg, T Michael Seigler
We present results from an experiment in which human subjects interact with an unknown dynamic system 40 times during a two-week period. During each interaction, subjects are asked to perform a command-following (i.e., pursuit tracking) task. Each subject's performance at that task improves from the first trial to the last trial. For each trial, we use subsystem identification to estimate each subject's feedforward (or anticipatory) control, feedback (or reactive) control, and feedback time delay. Over the 40 trials, the magnitudes of the identified feedback controllers and the identified feedback time delays do not change significantly...
January 26, 2017: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28138530/feedforward-and-feedback-frequency-dependent-interactions-in-a-large-scale-laminar-network-of-the-primate-cortex
#9
Jorge F Mejias, John D Murray, Henry Kennedy, Xiao-Jing Wang
Interactions between top-down and bottom-up processes in the cerebral cortex hold the key to understanding attentional processes, predictive coding, executive control, and a gamut of other brain functions. However, the underlying circuit mechanism remains poorly understood and represents a major challenge in neuroscience. We approached this problem using a large-scale computational model of the primate cortex constrained by new directed and weighted connectivity data. In our model, the interplay between feedforward and feedback signaling depends on the cortical laminar structure and involves complex dynamics across multiple (intralaminar, interlaminar, interareal, and whole cortex) scales...
November 2016: Science Advances
https://www.readbyqxmd.com/read/28131397/multi-loop-control-of-ups-inverter-with-a-plug-in-odd-harmonic-repetitive-controller
#10
Reza Razi, Mohammad-Sadegh Karbasforooshan, Mohammad Monfared
This paper proposes an improved multi-loop control scheme for the single-phase uninterruptible power supply (UPS) inverter by using a plug-in odd-harmonic repetitive controller to regulate the output voltage. In the suggested control method, the output voltage and the filter capacitor current are used as the outer and inner loop feedback signals, respectively and the instantaneous value of the reference voltage feedforwarded to the output of the controller. Instead of conventional linear (proportional-integral/-resonant) and conventional repetitive controllers, a plug-in odd-harmonic repetitive controller is employed in the outer loop to regulate the output voltage, which occupies less memory space and offers faster tracking performance compared to the conventional one...
January 25, 2017: ISA Transactions
https://www.readbyqxmd.com/read/28123025/sodium-pumps-mediate-activity-dependent-changes-in-mammalian-motor-networks
#11
Laurence D Picton, Filipe Nascimento, Matthew J Broadhead, Keith T Sillar, Gareth B Miles
: Ubiquitously expressed sodium pumps are best known for maintaining the ionic gradients and resting membrane potential required for generating action potentials. However, activity- and state-dependent changes in pump activity can also influence neuronal firing and regulate rhythmic network output. Here we demonstrate that changes in sodium pump activity regulate locomotor networks in the spinal cord of neonatal mice. The sodium pump inhibitor, ouabain, increased the frequency and decreased the amplitude of drug-induced locomotor bursting, effects that were dependent on the presence of the neuromodulator dopamine...
January 25, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28113940/learning-inverse-rig-mappings-by-nonlinear-regression
#12
Daniel Holden, Jun Saito, Taku Komura
We present a framework to design inverse rig-functions - functions that map low level representations of a character's pose such as joint positions or surface geometry to the representation used by animators called the animation rig. Animators design scenes using an animation rig, a framework widely adopted in animation production which allows animators to design character poses and geometry via intuitive parameters and interfaces. Yet most state-of-the-art computer animation techniques control characters through raw, low level representations such as joint angles, joint positions, or vertex coordinates...
November 11, 2016: IEEE Transactions on Visualization and Computer Graphics
https://www.readbyqxmd.com/read/28113871/a-telescopic-binary-learning-machine-for-training-neural-networks
#13
Mauro Brunato, Roberto Battiti
This paper proposes a new algorithm based on multiscale stochastic local search with binary representation for training neural networks [binary learning machine (BLM)]. We study the effects of neighborhood evaluation strategies, the effect of the number of bits per weight and that of the maximum weight range used for mapping binary strings to real values. Following this preliminary investigation, we propose a telescopic multiscale version of local search, where the number of bits is increased in an adaptive manner, leading to a faster search and to local minima of better quality...
March 18, 2016: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28113822/biomimetic-hybrid-feedback-feedforward-neural-network-learning-control
#14
Yongping Pan, Haoyong Yu
This brief presents a biomimetic hybrid feedback feedforward neural-network learning control (NNLC) strategy inspired by the human motor learning control mechanism for a class of uncertain nonlinear systems. The control structure includes a proportional-derivative controller acting as a feedback servo machine and a radial-basis-function (RBF) NN acting as a feedforward predictive machine. Under the sufficient constraints on control parameters, the closed-loop system achieves semiglobal practical exponential stability, such that an accurate NN approximation is guaranteed in a local region along recurrent reference traj- ectories...
March 30, 2016: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28105686/visual-tactile-processing-in-primary-somatosensory-cortex-emerges-before-cross-modal-experience
#15
Malte Bieler, Kay Sieben, Sandra Schildt, Brigitte Röder, Ileana L Hanganu-Opatz
The presumptive unisensory neocortical areas process multisensory information by oscillatory entrainment of neuronal networks via direct cortico-cortical projections. While neonatal unimodal experience has been identified as necessary for setting up the neuronal networks of multisensory processing, it is still unclear whether early cross-modal experience equally controls the ontogeny of multisensory processing. Here, we assess the development of visual-somatosensory interactions and their anatomical substrate by performing extracellular recordings of network activity in primary sensory cortices in vivo and assessing the cortico-cortical connectivity in pigmented rats...
January 20, 2017: Synapse
https://www.readbyqxmd.com/read/28101529/cortico-cortical-connections-of-primary-sensory-areas-and-associated-symptoms-in-migraine
#16
Duncan J Hodkinson, Rosanna Veggeberg, Aaron Kucyi, Koene R A van Dijk, Sophie L Wilcox, Steven J Scrivani, Rami Burstein, Lino Becerra, David Borsook
Migraine is a recurring, episodic neurological disorder characterized by headache, nausea, vomiting, and sensory disturbances. These events are thought to arise from the activation and sensitization of neurons along the trigemino-vascular pathway. From animal studies, it is known that thalamocortical projections play an important role in the transmission of nociceptive signals from the meninges to the cortex. However, little is currently known about the potential involvement of cortico-cortical feedback projections from higher-order multisensory areas and/or feedforward projections from principle primary sensory areas or subcortical structures...
November 2016: ENeuro
https://www.readbyqxmd.com/read/28100741/control-of-spike-transfer-at-hippocampal-mossy-fiber-synapses-in-vivo-by-gabaa-and-gabab-receptor-mediated-inhibition
#17
Stefano Zucca, Marilena Griguoli, Meryl Malézieux, Noëlle Grosjean, Mario Carta, Christophe Mulle
: Despite extensive studies in hippocampal slices and incentive from computational theories, the synaptic mechanisms underlying information transfer at mossy fiber (mf) connections between the dentate gyrus (DG) and CA3 neurons in vivo are still elusive. Here we used an optogenetic approach in mice to selectively target and control the activity of DG granule cells (GCs) while performing whole-cell and juxtacellular recordings of CA3 neurons in vivo In CA3 pyramidal cells (PCs), mf-CA3 synaptic responses consisted predominantly of an IPSP at low stimulation frequency (0...
January 18, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28069947/first-passage-time-approach-to-controlling-noise-in-the-timing-of-intracellular-events
#18
Khem Raj Ghusinga, John J Dennehy, Abhyudai Singh
In the noisy cellular environment, gene products are subject to inherent random fluctuations in copy numbers over time. How cells ensure precision in the timing of key intracellular events despite such stochasticity is an intriguing fundamental problem. We formulate event timing as a first-passage time problem, where an event is triggered when the level of a protein crosses a critical threshold for the first time. Analytical calculations are performed for the first-passage time distribution in stochastic models of gene expression...
January 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28069808/kinetic-modeling-and-analysis-of-the-akt-mechanistic-target-of-rapamycin-complex-1-mtorc1-signaling-axis-reveals-cooperative-feedforward-regulation
#19
Anisur Rahman, Jason M Haugh
Mechanistic target of rapamycin complex 1 (mTORC1) controls biosynthesis and has been implicated in uncontrolled cell growth in cancer. Although many details of mTORC1 regulation are well understood, a systems-level, predictive framework synthesizing those details is currently lacking. We constructed various mathematical models of mTORC1 activation mediated by Akt and aligned the model outputs to kinetic data acquired for growth factor-stimulated cells. A model based on a putative feedforward loop orchestrated by Akt consistently predicted how the pathway was altered by depletion of key regulatory proteins...
February 17, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28063499/analysis-of-phosphatidic-acid-binding-and-regulation-of-pipki-in-vitro-and-in-intact-cells
#20
L W R Tay, Z Wang, G Du
Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a lipid second messenger that regulates a wide array of essential cellular events, such as signal transduction, vesicle trafficking, actin cytoskeleton dynamics, adhesion, and motility. To control the spatiotemporal production of PI(4,5)P2, the activity of type 1 phosphotidylinositol-4-phosphate-5-kinases (PIPKIs) is tightly regulated by small GTPases and another signaling lipid, phosphatidic acid (PA). It is of interest that PI(4,5)P2 is also a critical cofactor for the activation of the PA-generating enzyme, phospholipase D (PLD)...
2017: Methods in Enzymology
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