Central Resetting of Neuromuscular Steady States May Underlie Rhythmical Arm Movements

2006 ◽  
Vol 96 (3) ◽  
pp. 1124-1134 ◽  
Author(s):  
Ksenia I. Ustinova ◽  
Anatol G. Feldman ◽  
Mindy F. Levin
Keyword(s):  
Steady State ◽  
Muscle Activation ◽  
Central Pattern Generators ◽  
Steady States ◽  
The Body ◽  
Proprioceptive Reflexes ◽  
Natural Tendency ◽  
Equilibrium Configurations ◽  
Pattern Generators ◽  
State Configuration

Changing the steady-state configuration of the body or its segments may be an important function of central pattern generators for locomotion and other rhythmical movements. Thereby, muscle activation, forces, and movement may emerge following a natural tendency of the neuromuscular system to achieve the current steady-state configuration. To verify that transitions between different steady states occur during rhythmical movements, we asked standing subjects to swing one or both arms synchronously or reciprocally at ∼0.8 Hz from the shoulder joints. In randomly selected cycles, one arm was transiently arrested by an electromagnetic device. Swinging resumed after some delay and phase resetting. During bilateral swinging, the nonperturbed arm often stopped before resuming swinging at a position that was close to either the extreme forward or the extreme backward arm position observed before the perturbation. Oscillations usually resumed when both arms arrived at similar extreme positions when a synchronous bilateral pattern was initially produced or at the opposite positions if the initial pattern was reciprocal. Results suggest that a central generator controls both arms as a coherent unit by producing transitions between its steady state (equilibrium) positions. By controlling these positions, the system may define the spatial boundaries of movement. At these positions, the system may halt the oscillations, resume them at a new phase (as observed in the present study), or initiate a new motor action. Our findings are relevant to locomotion and suggest that walking may also be generated by transitions between several equilibrium configurations of the body, possibly accomplished by modulation and gating of proprioceptive reflexes.

scholarly journals Dynamical Analysis of the SEIB Model for Brucellosis Transmission to the Dairy Cows with Immunological Threshold

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Wei Zhang ◽  
Juan Zhang ◽  
Yong-Ping Wu ◽  
Li Li
Keyword(s):  
Steady State ◽  
Global Stability ◽  
Dairy Cows ◽  
Immune Cells ◽  
Steady States ◽  
The Body ◽  
Infection Dose ◽  
The One ◽  
Immunological Threshold ◽  
Disease Free

As we all know, bacteria is different from virus which with certain types can be killed by the immune cells in the body. The brucellosis, a bacterial disease, can invade the body by indirect transmission from environment, which has not been researched by combining with immune cells. Considering the effects of immune cells, we put a minimum infection dose of brucellosis invading into the dairy cows as an immunological threshold and get a switch model. In this paper, we accomplish a thorough dynamics analysis of a SEIB switch model. On the one hand, we can get a disease-free and bacteria-free steady state and up to three endemic steady states which may be thoroughly analyzed in different cases of a minimum infection dose in a switch model. On the other hand, we calculate the basic reproduction number R0 and know that the disease-free and bacteria-free steady state is a global stability when R0<1, and the one of the endemic steady state is a conditionally global stability when R0>1. We find that different amounts of R0 may lead to different steady states of brucellosis, and considering the effects of immunology is more serious in mathematics and biology.

scholarly journals 0942 Alternating Leg Muscle Activation and Hypnagogic Foot Tremor in Children: Comparative Study of Polysomnographic and Clinico-Demographic Variables

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A358-A358
Author(s):  
G M de Menezes ◽  
L A Almeida ◽  
H H Sander ◽  
R M Fernandes ◽  
Á L Éckeli
Keyword(s):  
Muscle Activation ◽  
Central Pattern Generators ◽  
Respiratory Events ◽  
Obstructive Sleep ◽  
Significant Difference ◽  
Autonomic Activation ◽  
Clinical Consequences ◽  
Leg Muscle ◽  
Pattern Generators ◽  
And Gender

Abstract Introduction The clinical and polysomnographic meaning of the Alternating Leg Muscle Activation (ALMA) and Hypnagogic Foot Tremor (HFT) patterns in children is not known. Methods A descriptive study was carried out to identify the prevalence and polysomnographic characteristics of ALMA and HFT sequences in a sample of 122 children sequentially admitted in the sleep laboratory, with the analysis of clinical and demographic characteristics of the ALMA/HFT group in relation to a comparison group without this condition, paired by age and gender. Results Sample prevalence was 14.8% for any HFT/ALMA event, 13.1% for ALMA and 10.7% for HFT. In the HFT/ALMA group, the mean age was 8 years old (2-12 years old), 66.7% of males. Obstructive Sleep Apnea was observed in 75% of children, but HFT / ALMA sequences only occasionally occurred in association with respiratory events. The use of medications with monoaminergic activity was associated with the occurrence of HFT/ALMA, p=0,019. There was higher N1 sleep content in the HFT / ALMA group, p=0,0301. There was no significant difference between both groups regarding the other clinical-demographic or polysomnographic parameters analyzed. Autonomic activation represented by heart rate fluctuations often occurred in association with the HFT / ALMA sequences, irrespective of the occurrence of arousals, awakenings, other motor or respiratory events. Conclusion HFT / ALMA is a frequent condition in children that are referred to the sleep lab.The stereotypy of the HFT / ALMA series suggests that their origin might be motor central pattern generators, which are potentially influenced by substances with monoaminergic effect. The finding of higher superficial sleep content in children with HFT / ALMA may indicate greater susceptibility to alteration of pediatric sleep architecture by such subtle motor events. The possibility of clinical consequences and cardiovascular diseases should be considered in relation to the association of HFT / ALMA with observed autonomic activation. Support None.

scholarly journals An autonomous tail-beating cycle period expressed by a region-specific swimming pattern generator in the Ciona larva

2021 ◽  
Author(s):  
Takashi Hara ◽  
Shuya Hasegawa ◽  
Yasushi Iwatani ◽  
Atsuo S. Nishino
Keyword(s):  
Central Pattern Generators ◽  
Sister Group ◽  
Pattern Generator ◽  
The Body ◽  
Periodic Pattern ◽  
Cycle Period ◽  
Swimming Pattern ◽  
Aquatic Vertebrates ◽  
Pattern Generators ◽  
Region 10

Swimming locomotion in aquatic vertebrates, such as fish and tadpoles, is expressed through orchestrated operations of central pattern generators. These parallel neuronal circuits are ubiquitously distributed and mutually coupled along the spinal cord to express undulation patterns accommodated to efferent and afferent inputs. While such sets of schemes have been shown in vertebrates, the evolutionary origin of those mechanisms along the chordate phylogeny remains unclear. Ascidians, representing a sister group of vertebrates, give rise to tadpole larvae that freely swim in seawater. In this study, we tried to locate the swimming pattern generator in larvae of the ascidian Ciona by examining locomotor ability of segmented body fragments. Our experiments demonstrated necessary and sufficient pattern generator activity in a short region (~10% of the body length as the longest estimation) including the trunk-tail junction but excluding most of the trunk and tail with major sensory apparatuses therein. Moreover, we found that these "mid-piece" body fragments express periodic tail beating bursts with ~20-s intervals without any exogenous stimuli. Comparisons among temporal patterns of tail beating bursts expressed by the mid-piece fragments and by whole larvae placed under different sensory conditions suggested that the presence of parts other than the critical mid-piece had effects to shorten swimming burst intervals, especially in the dark, and also to expand the variance in burst durations. We propose that Ciona larvae perform swimming as modified representations of autonomous and periodic pattern generator drives, which operate locally in the region of the trunk-tail junction.

Impulses of activation but not motor modules are preserved in the locomotion of subacute stroke patients

2011 ◽  
Vol 106 (1) ◽  
pp. 202-210 ◽  
Author(s):  
Leonardo Gizzi ◽  
Jørgen Feldbæk Nielsen ◽  
Francesco Felici ◽  
Yuri P. Ivanenko ◽  
Dario Farina
Keyword(s):  
Healthy Subjects ◽  
Muscle Activation ◽  
Central Pattern Generators ◽  
Dependent Manner ◽  
Healthy Controls ◽  
Stroke Patients ◽  
Unaffected Side ◽  
Subacute Stroke ◽  
The Central Nervous System ◽  
Pattern Generators

It has been hypothesized that the coordinated activation of muscles is controlled by the central nervous system by means of a small alphabet of control signals (also referred to as activation signals) and motor modules (synergies). We analyzed the locomotion of 10 patients recently affected by stroke (maximum of 20 wk) and compared it with that of healthy controls. The aim was to assess whether the walking of subacute stroke patients is based on the same motor modules and/or activation signals as healthy subjects. The activity of muscles of the lower and upper limb and the trunk was measured and used for extracting motor modules. Four modules were sufficient to explain the majority of variance in muscle activation in both controls and patients. Modules from the affected side of stroke patients were different from those of healthy controls and from the unaffected side of stroke patients. However, the activation signals were similar between groups and between the affected and unaffected side of stroke patients, and were characterized by impulses at specific time instants within the gait cycle, underlying an impulsive controller of gait. In conclusion, motor modules observed in healthy subjects during locomotion are different from those used by subacute stroke patients, despite similar impulsive activation signals. We suggest that this pattern is consistent with a neuronal network in which the timing of activity generated by central pattern generators is directed to the motoneurons via a premotor network that distributes the activity in a task-dependent manner determined by sensory and descending control information.

scholarly journals Evaluating the energetics of entrainment in a human–machine coupled oscillator system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryan T. Schroeder ◽  
James L. Croft ◽  
John E. A. Bertram
Keyword(s):  
Central Pattern Generators ◽  
Metabolic Cost ◽  
The Body ◽  
Vertical Force ◽  
Wide Range ◽  
Metabolic Expenditure ◽  
Pattern Generators ◽  
Positive Work ◽  
Phase Relationships

AbstractDuring locomotion, humans sometimes entrain (i.e. synchronize) their steps to external oscillations: e.g. swaying bridges, tandem walking, bouncy harnesses, vibrating treadmills, exoskeletons. Previous studies have discussed the role of nonlinear oscillators (e.g. central pattern generators) in facilitating entrainment. However, the energetics of such interactions are unknown. Given substantial evidence that humans prioritize economy during locomotion, we tested whether reduced metabolic expenditure is associated with human entrainment to vertical force oscillations, where frequency and amplitude were prescribed via a custom mechatronics system during walking. Although metabolic cost was not significantly reduced during entrainment, individuals expended less energy when the oscillation forces did net positive work on the body and roughly selected phase relationships that maximize positive work. It is possible that individuals use mechanical cues to infer energy cost and inform effective gait strategies. If so, an accurate prediction may rely on the relative stability of interactions with the environment. Our results suggest that entrainment occurs over a wide range of oscillation parameters, though not as a direct priority for minimizing metabolic cost. Instead, entrainment may act to stabilize interactions with the environment, thus increasing predictability for the effective implementation of internal models that guide energy minimization.

scholarly journals Recent Insights into the Rhythmogenic Core of the Locomotor CPG

2021 ◽  
Vol 22 (3) ◽  
pp. 1394
Author(s):  
Vladimir Rancic ◽  
Simon Gosgnach
Keyword(s):  
Neural Network ◽  
Spinal Cord ◽  
Muscle Activation ◽  
Central Pattern Generators ◽  
Cell Types ◽  
Genetic Approach ◽  
Spinal Neurons ◽  
Locomotor Rhythm ◽  
Key Features ◽  
Pattern Generators

In order for locomotion to occur, a complex pattern of muscle activation is required. For more than a century, it has been known that the timing and pattern of stepping movements in mammals are generated by neural networks known as central pattern generators (CPGs), which comprise multiple interneuron cell types located entirely within the spinal cord. A genetic approach has recently been successful in identifying several populations of spinal neurons that make up this neural network, as well as the specific role they play during stepping. In spite of this progress, the identity of the neurons responsible for generating the locomotor rhythm and the manner in which they are interconnected have yet to be deciphered. In this review, we summarize key features considered to be expressed by locomotor rhythm-generating neurons and describe the different genetically defined classes of interneurons which have been proposed to be involved.

scholarly journals Increasing viscosity helps explain locomotor control in swimming Polypterus seneglus

2021 ◽  
Author(s):  
K Lutek ◽  
E M Standen
Keyword(s):  
Motor Control ◽  
Sensory Feedback ◽  
Muscle Activation ◽  
Central Pattern Generators ◽  
Sensory Information ◽  
High Viscosity ◽  
Control Input ◽  
Polypterus Senegalus ◽  
Similar Motor ◽  
Pattern Generators

Abstract Locomotion relies on the successful integration of sensory information to adjust brain commands and basic motor rhythms created by central pattern generators. It is not clearly understood how altering the sensory environment impacts control of locomotion. In an aquatic environment, mechanical sensory feedback to the animal can be readily altered by adjusting water viscosity. Computer modeling of fish swimming systems show that, without sensory feedback, high viscosity systems dampen kinematic output despite similar motor control input. We recorded muscle activity and kinematics of six Polypterus senegalus in four different viscosities of water from 1 cP (normal water) to 40 cP. In high viscosity, P. senegalus exhibit increased body curvature, body wavespeed and body and pectoral fin frequency during swimming. These changes are the result of increased muscle activation intensity and maintain voluntary swimming speed. Unlike the sensory deprived model, intact sensory feedback allows fish to adjust swimming motor control and kinematic output in high viscous water but maintain typical swimming coordination.

Evolution and Development of a Central Pattern Generator for the Swimming of a Lamprey

1999 ◽  
Vol 5 (3) ◽  
pp. 247-269 ◽  
Author(s):  
Auke Jan Ijspeert ◽  
Jérôme Kodjabachian
Keyword(s):  
Neural Control ◽  
Fitness Function ◽  
Central Pattern Generators ◽  
The Body ◽  
Programming Approach ◽  
Two Dimensional ◽  
Developmental Programs ◽  
Cellular Division ◽  
Input Signals ◽  
Pattern Generators

This article describes the design of neural control architectures for locomotion using an evolutionary approach. Inspired by the central pattern generators found in animals, we develop neural controllers that can produce the patterns of oscillations necessary for the swimming of a simulated lamprey. This work is inspired by Ekeberg's neuronal and mechanical model of a lamprey [11] and follows experiments in which swimming controllers were evolved using a simple encoding scheme [25, 26]. Here, controllers are developed using an evolutionary algorithm based on the SGOCE encoding [31, 32] in which a genetic programming approach is used to evolve developmental programs that encode the growing of a dynamical neural network. The developmental programs determine how neurons located on a two-dimensional substrate produce new cells through cellular division and how they form efferent or afferent interconnections. Swimming controllers are generated when the growing networks eventually create connections to the muscles located on both sides of the rectangular substrate. These muscles are part of a two-dimensional mechanical simulation of the body of the lamprey in interaction with water. The motivation of this article is to develop a method for the design of control mechanisms for animal-like locomotion. Such a locomotion is characterized by a large number of actuators, a rhythmic activity, and the fact that efficient motion is only obtained when the actuators are well coordinated. The task of the control mechanism is therefore to transform commands concerning the speed and direction of motion into the signals sent to the multiple actuators. We define a fitness function, based on several simulations of the controller with different commands settings, that rewards the capacity of modulating the speed and the direction of swimming in response to simple, varying input signals. Central pattern generators are thus evolved capable of producing the relatively complex patterns of oscillations necessary for swimming. The best solutions generate traveling waves of neural activity, and propagate, similarly to the swimming of a real lamprey, undulations of the body from head to tail propelling the lamprey forward through water. By simply varying the amplitude of two input signals, the speed and the direction of swimming can be modulated.

Effect of Central Pattern Generators Depended Different Walking Strategies on Gait Ability of Patients after Stroke

2017 ◽  
Vol 27 (2) ◽  
pp. 40
Author(s):  
Hua WU ◽  
Zaihua RU ◽  
Congying XU ◽  
Xudong GU ◽  
Jianming FU
Keyword(s):  
Central Pattern Generators ◽  
Pattern Generators
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