scholarly journals Nonlinear robust compensator design for postural control of a biomechanical model with delayed feedback

2020 ◽  
Vol 53 (3-4) ◽  
pp. 679-690
Author(s):  
Nadia Sultan ◽  
Muhammad Najam ul Islam ◽  
Asif Mahmood Mughal
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Feedback Linearization ◽  
Sensory Feedback ◽  
Biomechanical Model ◽  
Joint Torque ◽  
Transmission Delays ◽  
Neural Transmission ◽  
Simulation Results ◽  
Nonlinear Robust

Postural stability and balance regulation is an intricate neurophysiological task which entails coordination of movements for successful execution. This task is proficiently regulated by central nervous system. The sensory feedback through muscles via proprioceptors has neural transmission delays which make the movement coordination and computations by central nervous system a complex problem to deal with. This paper addresses a nonlinear robust technique based on feedback linearization for postural stabilization of a single-link biomechanical model in the presence of physiological latencies. We included neural transmission delays in sensory feedback from proprioceptors. We developed [Formula: see text] optimal controller and integrated it with feedback linearization to calculate the joint torque for the biomechanical task. This modeling scheme is simulated in MATLAB/SimMechanics, and the simulation results for the nonlinear biomechanical model are developed. The joint torque compensates for the delays and settles the motion profiles within anatomical constraints. The position profile shows a bit higher overshoot (0.02, 0.03 rad) in case of delays; however, the settling time is same for the profiles with and without delay. The extensor torque is same for all profiles; however, the flexion torque increases for the delayed case. The simulation results show the applicability of this scheme for further analysis of the biomechanical task.

Sensory feedback therapy as a modality of treatment in central nervous system disorders of voluntary movement

Neurology ◽  
1974 ◽  
Vol 24 (10) ◽  
pp. 925-925 ◽  
Author(s):  
J. BRUDNY ◽  
J. KOREIN ◽  
L. LEVIDOW ◽  
B. B. GRYNBAUM ◽  
A. LIEBERMAN ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Voluntary Movement ◽  
Sensory Feedback ◽  
Central Nervous System Disorders

scholarly journals Pendulum test: Quantified assessment of the type and level of spasticity in persons with central nervous system lesions

2018 ◽  
Vol 15 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Dejan Popovic ◽  
Tadej Bajd
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Knee Joint ◽  
Soft Tissues ◽  
Technological Development ◽  
Lower Leg ◽  
Elastic Stiffness ◽  
Joint Torque ◽  
Good Representation ◽  
Pendulum Test

The development of a comprehensive computational model of the pendulum test which is appropriate for the analysis of the pathologic behavior of the leg in humans with the central nervous system (CNS) lesion is presented in this review. The model relates to the pendulum movement of the lower leg (shank and the foot) in the lateral plane due to the gravity and involuntary contractions of the muscles. The viscous damping and elastic stiffness reflect the soft tissues and friction in the knee joint. To quantify the pathologic activity of paralyzed muscles a reflex torque was added to the gravity generated knee joint torque. The knee joint encoder, accelerometers and gyroscopes positioned along the shank and thigh, and EMG amplifiers were used to acquire data for the illustration of the validity of the model. We show that the linear model of the movement of the lower leg is not a good representation of the motor impairment. We show that the model expanded with the reflex torque affecting the movement is well suited for the pendulum analysis. The timing of the reflex torques can be determined from the EMG recordings. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR35003] <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/SJEE2002257E">10.2298/SJEE2002257E</a><u></b></font>

1624: A Model to Assess the Sensory Feedback From the External Genitalia to the Central Nervous System in Female Rat

2004 ◽  
Vol 171 (4S) ◽  
pp. 429-429
Author(s):  
François Giuliano ◽  
Kamal Rahmouni ◽  
Laurent Alexandre ◽  
Stéphane Droupy ◽  
Jacques Bernabé
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Feedback ◽  
External Genitalia ◽  
Female Rat ◽  
The Central Nervous System

Effect of Initial Lean on Scaling of Postural Feedback Responses

2005 ◽  
Vol 277-279 ◽  
pp. 142-147
Author(s):  
Suk Yung Park ◽  
Fay B. Horak ◽  
Arthur D. Kuo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Feedback Control ◽  
Ankle Joint ◽  
Joint Torque ◽  
Postural Responses ◽  
Body Dynamics ◽  
The Central Nervous System ◽  
Biomechanical Constraints ◽  
Perturbation Magnitude

We examined how the central nervous system adjusts postural responses to an increased postural challenge due to an initial lean. Postural feedback responses scale to accommodate biomechanical constraints, such as an allowable ankle joint torque. Initial forward leaning, which is observed among the elderly who are inactive or afraid of falling, brings subjects near to the limit of stability and makes the biomechanical constraints more difficult to obey. We hypothesized that the central nervous system is aware of body dynamics and restrains postural responses when subjects initially lean forward. To test this hypothesis, fast backwards perturbations of various magnitudes were applied to 12 healthy young subjects (3 male, 9 female) aged 20 to 32 years. The subjects were instructed to stand quietly on a hydraulic servo-controlled force platform with their arms crossed over their chests, then to recover from a perturbation by returning to their upright position, without stepping or lifting their heels off the ground, if possible. Initially, the subjects were either standing upright or leaning forward. The force platform was movable in the translational direction and programmed to move backward with various ramp displacements ranging from 1.2 to 15 cm, all with the duration of 275 msec. For each trial, the kinematics and ground reaction force data were recorded, then used to compute the net joint torques, employing a least squares inverse dynamics method. Optimization methods were used to identify a set of equivalent feedback control gains for each trial so that the biomechanical model incorporating this feedback control would reproduce the empirical response. The results showed that the kinematics, joint torque, and feedback gains gradually scaled as a function of the perturbation magnitude before they reached the biomechanical constraint, and the scaling became more severe with an initial forward lean. For example, the model suggested that the magnitude of the ankle joint angle feedback to ankle torque was smaller in the leaning trials than in the initially upright trials, as if the subjects experienced a larger postural perturbation in the leaning trials. These results imply that the central nervous system restrained the postural responses to accommodate the additional biomechanical constraint imposed by the forward posture, thereby suggesting that the central nervous system is aware of body dynamics and biomechanical constraints. The scaling of the postural feedback gains with the perturbation magnitude and initial lean indicates that the postural control can be interpreted as a feedback scheme with scalable gains.

scholarly journals Controlling Effects of Astrocyte on Neuron Behavior in Tripartite Synapse Using VHDL–AMS

Mathematics ◽  
2021 ◽  
Vol 9 (21) ◽  
pp. 2700
Author(s):  
Osman Taylan ◽  
Mona Abusurrah ◽  
Ehsan Eftekhari-Zadeh ◽  
Ehsan Nazemi ◽  
Farheen Bano ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Coupling Coefficients ◽  
Synaptic Terminal ◽  
Tripartite Synapse ◽  
The Central Nervous System ◽  
Simulation Results ◽  
Synapse Model ◽  
The Brain ◽  
Post Synaptic Neuron

Astrocyte cells form the largest cell population in the brain and can influence neuron behavior. These cells provide appropriate feedback control in regulating neuronal activities in the Central Nervous System (CNS). This paper presents a set of equations as a model to describe the interactions between neurons and astrocyte. A VHDL–AMS-based tripartite synapse model that includes a pre-synaptic neuron, the synaptic terminal, a post-synaptic neuron, and an astrocyte cell is presented. In this model, the astrocyte acts as a controller module for neurons and can regulates the spiking activity of them. Simulation results show that by regulating the coupling coefficients of astrocytes, spiking frequency of neurons can be reduced and the activity of neuronal cells is modulated.

scholarly journals Visual prediction: Psychophysics and neurophysiology of compensation for time delays

2008 ◽  
Vol 31 (2) ◽  
pp. 179-198 ◽  
Author(s):  
Romi Nijhawan
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Visual Awareness ◽  
Motor Planning ◽  
Luminance Contrast ◽  
Planning System ◽  
Delay Compensation ◽  
Neural Transmission ◽  
The Central Nervous System ◽  
Sensory Processes

AbstractA necessary consequence of the nature of neural transmission systems is that as change in the physical state of a time-varying event takes place, delays produce error between the instantaneous registered state and the external state. Another source of delay is the transmission of internal motor commands to muscles and the inertia of the musculoskeletal system. How does the central nervous system compensate for these pervasive delays? Although it has been argued that delay compensation occurs late in the motor planning stages, even the earliest visual processes, such as phototransduction, contribute significantly to delays. I argue that compensation is not an exclusive property of the motor system, but rather, is a pervasive feature of the central nervous system (CNS) organization. Although the motor planning system may contain a highly flexible compensation mechanism, accounting not just for delays but also variability in delays (e.g., those resulting from variations in luminance contrast, internal body temperature, muscle fatigue, etc.), visual mechanisms also contribute to compensation. Previous suggestions of this notion of “visual prediction” led to a lively debate producing re-examination of previous arguments, new analyses, and review of the experiments presented here. Understanding visual prediction will inform our theories of sensory processes and visual perception, and will impact our notion of visual awareness.

scholarly journals Modular organization of the murine locomotor pattern in presence and absence of sensory feedback from muscle spindles

2018 ◽  
Author(s):  
Alessandro Santuz ◽  
Turgay Akay ◽  
William P. Mayer ◽  
Tyler L. Wells ◽  
Arno Schroll ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Feedback ◽  
Genetically Modified ◽  
Muscle Spindles ◽  
Modular Organization ◽  
Muscle Synergies ◽  
Activation Patterns ◽  
The Central Nervous System ◽  
Genetically Modified Mice

AbstractFor exploiting terrestrial and aquatic locomotion, vertebrates must build their locomotor patterns based on an enormous amount of variables. The great number of muscles and joints, together with the constant need for sensory feedback information (e.g. proprioception), make the task of creating and controlling movement a problem with overabundant degrees of freedom. It is widely accepted that the central nervous system might simplify the creation and control of movement. This could happen through the generation of activation patterns, which are common to many different muscles, rather than specific to individual muscles. These activation patterns, called muscle synergies, can be extracted from electromyographic data and describe the modular organization of movement. We extracted muscle synergies from the hindlimb muscle activities of wild type and genetically modified mice, in which sensory feedback from muscle spindles is eliminated. Muscle spindle-deficient mice underwent a modification of the temporal structure (motor primitives) of muscle synergies that resulted in diminished functionality during walking. In addition, both the temporal and spatial components (motor modules) of muscle synergies were severely affected when external perturbations were introduced of when animals were immersed in water. These findings show that group Ia/II sensory feedback from muscle spindles regulates motor function in normal and perturbed walking. Moreover, when group Ib Golgi tendon organ feedback is lacking due to the reduction of gravitational load in conditions of enhanced buoyancy, the modular organization of swimming is almost completely compromised.Significance statementLocomotion on land and in water requires the coordination of a great number of muscle activations and joint movements. Moreover, constant feedback about the position of own body parts in relation to the surrounding environment and the body itself (proprioception) is required to maintain stability and avoid failure. The theory of muscle synergies states that the central nervous system might control muscles in orchestrated groups (synergies) rather than individually. We used this concept on genetically modified mice, lacking one of the two classes of proprioceptors. Our results provide evidence that proprioceptive feedback is required by the central nervous system to accurately tune the modular organization of locomotion.

Neurotropic enteroviruses co-opt “fair-weather-friend” commensal gut microbiota to drive host infection and central nervous system disturbances

2019 ◽  
Vol 42 ◽  
Author(s):  
Kevin B. Clark
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Gut Bacteria ◽  
Infection Cycle ◽  
Fair Weather ◽  
Host Health ◽  
Microbe Interactions ◽  
Animal Hosts ◽  
Host Infection ◽  
Neuropsychiatric Conditions

Abstract Some neurotropic enteroviruses hijack Trojan horse/raft commensal gut bacteria to render devastating biomimicking cryptic attacks on human/animal hosts. Such virus-microbe interactions manipulate hosts’ gut-brain axes with accompanying infection-cycle-optimizing central nervous system (CNS) disturbances, including severe neurodevelopmental, neuromotor, and neuropsychiatric conditions. Co-opted bacteria thus indirectly influence host health, development, behavior, and mind as possible “fair-weather-friend” symbionts, switching from commensal to context-dependent pathogen-like strategies benefiting gut-bacteria fitness.

Sign in / Sign up

Export Citation Format

Share Document