Read by QxMD icon Read

feedforward control

Zachary C Thumser, Andrew B Slifkin, Dylan T Beckler, Paul D Marasco
Fitts' law models the relationship between amplitude, precision, and speed of rapid movements. It is widely used to quantify performance in pointing tasks, study human-computer interaction, and generally to understand perceptual-motor information processes, including research to model performance in isometric force production tasks. Applying Fitts' law to an isometric grip force task would allow for quantifying grasp performance in rehabilitative medicine and may aid research on prosthetic control and design...
2018: Frontiers in Psychology
Marta Robledo, Jan-Philip Schlüter, Lars O Loehr, Uwe Linne, Stefan P Albaum, José I Jiménez-Zurdo, Anke Becker
Adjustment of cell cycle progression is crucial for bacterial survival and adaptation under adverse conditions. However, the understanding of modulation of cell cycle control in response to environmental changes is rather incomplete. In α-proteobacteria, the broadly conserved cell cycle master regulator CtrA underlies multiple levels of control, including coupling of cell cycle and cell differentiation. CtrA levels are known to be tightly controlled through diverse transcriptional and post-translational mechanisms...
2018: Frontiers in Microbiology
Mohsen Sayyah, Michael J Hiley, Mark A King, Maurice R Yeadon
In springboard diving, low variability in takeoff conditions and in the somersault orientation angle at water entry is to be expected since consistency and accuracy are necessary for a good dive. A diver's adjustment of body configuration during flight may be a deliberate compensation for variations in takeoff conditions, leading to increased joint angle variability and decreased entry angle variability. The aim of this research was to investigate the extent to which a diver pre-plans the aerial phase and then makes adjustments in flight to control the entry angle in one metre springboard forward dives...
May 5, 2018: Human Movement Science
Anais Grangeray-Vilmint, Antoine M Valera, Arvind Kumar, Philippe Isope
The balance between excitation (E) and inhibition (I) in neuronal networks controls the firing rate of principal cells through simple network organization, such as feedforward inhibitory circuits. Here, we demonstrate in male mice, that at the granule cell (GrC)-molecular layer interneuron (MLI)-Purkinje cell (PC) pathway of the mouse cerebellar cortex, E/I balance is dynamically controlled by short-term dynamics during bursts of stimuli, shaping cerebellar output. Using a combination of electrophysiological recordings, optogenetic stimulation and modeling, we describe the wide range of bidirectional changes in PC discharge triggered by GrC bursts, from robust excitation to complete inhibition...
May 2, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Jian Li, Raoqiao Shi, Chuanlong Xu, Shimin Wang
The selective catalytic reduction (SCR) system, as one principal flue-gas treatment method employed for the NOx emission control of coal-fired power plant, is nonlinear and time-varying with great inertia and large time delay. It is difficult for the present SCR control system to achieve satisfactory performance with the traditional feedback and feedforward control strategies. Although some improved control strategies, such as the Smith predictor control and the model predictive control, have been proposed for this issue, a well-matched identification model is essentially required to realize a superior control of the SCR system...
April 27, 2018: Environmental Technology
Roozbeh Behroozmand, Stacey Sangtian
The present study used event-related potential (ERP) recordings to investigate the neural mechanisms of sensorimotor adaptation in response to altered auditory feedback (AAF) during vocal production. 12 healthy speakers were tested under a vocal motor adaptation paradigm in which the fundamental frequency (F0) of their voice auditory feedback was pitch-shifted downward by one semi-tone (- 100 cents) during vowel vocalizations. Behavioral results revealed that subjects adapted to AAF by producing opposing (upward) responses to pitch-shift stimuli, and this adaptive behavior persisted after feedback alteration was removed (washout)...
April 25, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Hikaru Yokoyama, Koji Sato, Tetsuya Ogawa, Shin-Ichiro Yamamoto, Kimitaka Nakazawa, Noritaka Kawashima
The adaptability of human bipedal locomotion has been studied using split-belt treadmill walking. Most of previous studies utilized experimental protocol under remarkably different split ratios (e.g. 1:2, 1:3, or 1:4). While, there is limited research with regard to adaptive process under the small speed ratios. It is important to know the nature of adaptive process under ratio smaller than 1:2, because systematic evaluation of the gait adaptation under small to moderate split ratios would enable us to examine relative contribution of two forms of adaptation (reactive feedback and predictive feedforward control) on gait adaptation...
2018: PloS One
Naji A Alibeji, Vahidreza Molazadeh, Brad E Dicianno, Nitin Sharma
A hybrid walking neuroprosthesis that combines functional electrical stimulation (FES) with a powered lower limb exoskeleton can be used to restore walking in persons with paraplegia. It provides therapeutic benefits of FES and torque reliability of the powered exoskeleton. Moreover, by harnessing metabolic power of muscles via FES, the hybrid combination has a potential to lower power consumption and reduce actuator size in the powered exoskeleton. Its control design, however, must overcome the challenges of actuator redundancy due to the combined use of FES and electric motor...
2018: Frontiers in Neuroscience
Melanie A Gainey, Joseph W Aman, Daniel E Feldman
Rapid plasticity of layer (L) 2/3 inhibitory circuits is an early step in sensory cortical map plasticity, but its cellular basis is unclear. We show that, in mice of either sex, 1 day whisker deprivation drives rapid loss of L4-evoked feedforward inhibition and more modest loss of feedforward excitation in L2/3 pyramidal (PYR) cells, increasing E-I conductance ratio. Rapid disinhibition was due to reduced L4-evoked spiking by L2/3 parvalbumin (PV) interneurons, caused by reduced PV intrinsic excitability. This included elevated PV spike threshold, associated with an increase in low-threshold, voltage activated delayed rectifier (presumed Kv1) and A-type potassium currents...
April 20, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Tiffani Kittilstved, Kevin J Reilly, Ashley W Harkrider, Devin Casenhiser, David Thornton, David E Jenson, Tricia Hedinger, Andrew L Bowers, Tim Saltuklaroglu
Objective : To determine whether changes in sensorimotor control resulting from speaking conditions that induce fluency in people who stutter (PWS) can be measured using electroencephalographic (EEG) mu rhythms in neurotypical speakers. Methods : Non-stuttering (NS) adults spoke in one control condition (solo speaking) and four experimental conditions (choral speech, delayed auditory feedback (DAF), prolonged speech and pseudostuttering). Independent component analysis (ICA) was used to identify sensorimotor μ components from EEG recordings...
2018: Frontiers in Human Neuroscience
Cian McCafferty, François David, Marcello Venzi, Magor L Lőrincz, Francis Delicata, Zoe Atherton, Gregorio Recchia, Gergely Orban, Régis C Lambert, Giuseppe Di Giovanni, Nathalie Leresche, Vincenzo Crunelli
Behaviorally and pathologically relevant cortico-thalamo-cortical oscillations are driven by diverse interacting cell-intrinsic and synaptic processes. However, the mechanism that gives rise to the paroxysmal oscillations of absence seizures (ASs) remains unknown. Here we report that, during ASs in behaving animals, cortico-thalamic excitation drives thalamic firing by preferentially eliciting tonic rather than T-type Ca 2+ channel (T-channel)-dependent burst firing in thalamocortical (TC) neurons and by temporally framing thalamic output via feedforward reticular thalamic (NRT)-to-TC neuron inhibition...
May 2018: Nature Neuroscience
Jungeui Hong, Nathan Brandt, Farah Abdual-Rahman, Ally W H Yang, Timothy R Hughes, David Gresham
We studied adaptive evolution of gene expression using long-term experimental evolution of Saccharomyces cerevisiae in ammonium-limited chemostats. We found repeated selection for non-synonymous variation in the DNA binding domain of the transcriptional activator, GAT1, which functions with the repressor, DAL80 in an incoherent type-1 feedforward loop (I1-FFL) to control expression of the high affinity ammonium transporter gene, MEP2. Missense mutations in the DNA binding domain of GAT1 reduce its binding to the GATAA consensus sequence...
April 5, 2018: ELife
Mingsian R Bai, Weichi Pan, Hungyu Chen
Active noise control (ANC) of headsets is revisited in this paper. An in-depth electroacoustic analysis of the combined loudspeaker-cavity headset system is conducted on the basis of electro-mechano-acoustical analogous circuits. Model matching of the primary path and the secondary path leads to a feedforward control architecture. The ideal controller sheds some light on the key parameters that affect the noise reduction performance. Filtered-X least-mean-squares algorithm is employed to implement the feedforward controller on a digital signal processor...
March 2018: Journal of the Acoustical Society of America
Stephen J Elliott, Woomin Jung, Jordan Cheer
Local active sound control systems provide useful reductions in noise within a zone of quiet which only extends to about one tenth of an acoustic wavelength. If active control is required above a few hundred hertz, this generally limits the movement of a listener to unrealistically small changes in head position. We describe a local active sound control system using a fixed array of monitoring microphones, in which the pressures at the ear positions are estimated from these microphone signals using head position information from an optical head tracker...
March 29, 2018: Scientific Reports
Marko Markovic, Meike A Schweisfurth, Leonard F Engels, Tashina Bentz, Daniela Wüstefeld, Dario Farina, Strahinja Dosen
BACKGROUND: To effectively replace the human hand, a prosthesis should seamlessly respond to user intentions but also convey sensory information back to the user. Restoration of sensory feedback is rated highly by the prosthesis users, and feedback is critical for grasping in able-bodied subjects. Nonetheless, the benefits of feedback in prosthetics are still debated. The lack of consensus is likely due to the complex nature of sensory feedback during prosthesis control, so that its effectiveness depends on multiple factors (e...
March 27, 2018: Journal of Neuroengineering and Rehabilitation
Jakob Lorentzen, Maria Willerslev-Olsen, Helle Hüche Larsen, Christian Svane, Christian Forman, Rasmus Frisk, Simon Francis Farmer, Uwe Kersting, Jens Bo Nielsen
Toe walking requires careful control of the ankle muscles in order to absorb the impact of ground contact and maintain a stable position of the joint. The present study aimed to clarify the peripheral and central neural mechanisms involved. Fifteen healthy adults walked on a treadmill (3.0 km h-1 ). Tibialis Anterior (TA) and Soleus (Sol) EMG, knee and ankle joint angles and gastrocnemius-soleus muscle fascicle lengths were recorded. Peripheral and central contributions to the EMG activity were assessed by afferent blockade, H-reflex testing, Transcranial Magnetic Brain Stimulation (TMS) and sudden unloading of the planter flexor muscle-tendon complex...
March 23, 2018: Journal of Physiology
Troy J Rand, Mukul Mukherjee
The sensorimotor system prefers sway velocity information when maintaining upright posture. Sway velocity has a unique characteristic of being persistent on a short time-scale and anti-persistent on a longer time-scale. The time where the transition from persistence to anti-persistence occurs provides information about how sway velocity is controlled. It is, however, not clear what factors affect shifts in this transition point. This research investigated postural responses to support surface movements of different temporal correlations and movement velocities...
March 21, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Elham Fathiazar, Gerrit Hilgen, Jutta Kretzberg
The tiny ensemble of neurons in the leech ganglion can discriminate the locations of touch stimuli on the skin as precisely as a human fingertip. The leech uses this ability to locally bend the body-wall away from the stimulus. It is assumed that a three-layered feedforward network of pressure mechanoreceptors, interneurons, and motor neurons controls this behavior. Most previous studies identified and characterized the local bend network based on electrical stimulation of a single pressure mechanoreceptor, which was sufficient to trigger the local bend response...
2018: Frontiers in Physiology
Thomas H Segall-Shapiro, Eduardo D Sontag, Christopher A Voigt
The internal environment of growing cells is variable and dynamic, making it difficult to introduce reliable parts, such as promoters, for genetic engineering. Here, we applied control-theoretic ideas to design promoters that maintained constant levels of expression at any copy number. Theory predicts that independence to copy number can be achieved by using an incoherent feedforward loop (iFFL) if the negative regulation is perfectly non-cooperative. We engineered iFFLs into Escherichia coli promoters using transcription-activator-like effectors (TALEs)...
March 19, 2018: Nature Biotechnology
Fabien Cignetti, Marianne Vaugoyeau, Aurelie Fontan, Marianne Jover, Marie-Odile Livet, Catherine Hugonenq, Frédérique Audic, Brigitte Chabrol, Christine Assaiante
BACKGROUND AND AIM: Feedforward and online controls are two facets of predictive motor control from internal models, which is suspected to be impaired in learning disorders. We examined whether the feedforward component is affected in children (8-12 years) with developmental dyslexia (DD) and/or with developmental coordination disorder (DCD) compared to typically developing (TD) children. METHODS: Children underwent a bimanual unloading paradigm during which a load supported to one arm, the postural arm, was either unexpectedly unloaded by a computer or voluntary unloaded by the subject with the other arm...
May 2018: Research in Developmental Disabilities
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"