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https://www.readbyqxmd.com/read/28341164/expectation-violation-and-attention-to-pain-jointly-modulate-neural-gain-in-somatosensory-cortex
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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 21, 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
#12
(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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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