Neural control of rhythmic, cyclical human arm movement: task dependency, nerve specificity and phase modulation of cutaneous reflexes

2001 ◽  
Vol 537 (3) ◽  
pp. 1033-1045 ◽  
Author(s):  
E P. Zehr ◽  
A. Kido
Keyword(s):  
Phase Modulation ◽  
Neural Control ◽  
Arm Movement ◽  
Cutaneous Reflexes ◽  
Human Arm ◽  
Task Dependency

scholarly journals Neural control of rhythmic arm cycling after stroke

2012 ◽  
Vol 108 (3) ◽  
pp. 891-905 ◽  
Author(s):  
E. Paul Zehr ◽  
Pamela M. Loadman ◽  
Sandra R. Hundza
Keyword(s):  
Neural Control ◽  
Arm Movement ◽  
Constant Current ◽  
Cycle Phase ◽  
Emg Activity ◽  
Reflex Modulation ◽  
Cutaneous Reflexes ◽  
Cutaneous Reflex ◽  
Arm Cycling ◽  
Modulation Pattern

Disordered reflex activity and alterations in the neural control of walking have been observed after stroke. In addition to impairments in leg movement that affect locomotor ability after stroke, significant impairments are also seen in the arms. Altered neural control in the upper limb can often lead to altered tone and spasticity resulting in impaired coordination and flexion contractures. We sought to address the extent to which the neural control of movement is disordered after stroke by examining the modulation pattern of cutaneous reflexes in arm muscles during arm cycling. Twenty-five stroke participants who were at least 6 mo postinfarction and clinically stable, performed rhythmic arm cycling while cutaneous reflexes were evoked with trains (5 × 1.0-ms pulses at 300 Hz) of constant-current electrical stimulation to the superficial radial (SR) nerve at the wrist. Both the more (MA) and less affected (LA) arms were stimulated in separate trials. Bilateral electromyography (EMG) activity was recorded from muscles acting at the shoulder, elbow, and wrist. Analysis was conducted on averaged reflexes in 12 equidistant phases of the movement cycle. Phase-modulated cutaneous reflexes were present, but altered, in both MA and LA arms after stroke. Notably, the pattern was “blunted” in the MA arm in stroke compared with control participants. Differences between stroke and control were progressively more evident moving from shoulder to wrist. The results suggest that a reduced pattern of cutaneous reflex modulation persists during rhythmic arm movement after stroke. The overall implication of this result is that the putative spinal contributions to rhythmic human arm movement remain accessible after stroke, which has translational implications for rehabilitation.

Forward and Backward Arm Cycling Are Regulated by Equivalent Neural Mechanisms

2005 ◽  
Vol 93 (1) ◽  
pp. 633-640 ◽  
Author(s):  
E. Paul Zehr ◽  
Sandra R. Hundza
Keyword(s):  
Neural Control ◽  
Arm Movement ◽  
Movement Direction ◽  
Reflex Modulation ◽  
Neural Activation ◽  
Cutaneous Reflexes ◽  
Leg Muscles ◽  
Cutaneous Reflex ◽  
Arm Cycling ◽  
Walking Activity

It was shown some time ago that cutaneous reflexes were phase-reversed when comparing forward and backward treadmill walking. Activity of central-pattern-generating networks (CPG) regulating neural activity for locomotion was suggested as a mechanism involved in this “program reversal.” We have been investigating the neural control of arm movements and the role for CPG mechanisms in regulating rhythmic arm cycling. The purpose of this study was to evaluate the pattern of muscle activity and reflex modulation when comparing forward and backward arm cycling. During rhythmic arm cycling (forward and backward), cutaneous reflexes were evoked with trains (5 × 1.0 ms pulses at 300 Hz) of electrical stimulation delivered to the superficial radial (SR) nerve at the wrist. Electromyographic (EMG) recordings were made bilaterally from muscles acting at the shoulder, elbow, and wrist. Analysis was conducted on specific sections of the movement cycle after phase-averaging contingent on the timing of stimulation in the movement cycle. EMG patterns for rhythmic arm cycling are similar during both forward and backward motion. Cutaneous reflex amplitudes were similarly modulated at both early and middle latency irrespective of arm cycling direction. That is, at similar phases in the movement cycle, responses of corresponding sign and amplitude were seen regardless of movement direction. The results are generally parallel to the observations seen in leg muscles after stimulation of cutaneous nerves in the foot during forward and backward walking and provide further evidence for CPG activity contributing to neural activation and reflex modulation during rhythmic arm movement.

Minimum muscle tension-change model for human arm movement

1990 ◽  
Vol 11 ◽  
pp. S54 ◽  
Author(s):  
Yoji Uno ◽  
Mitsuo Kawato ◽  
Ryoji Suzuki
Keyword(s):  
Muscle Tension ◽  
Arm Movement ◽  
Change Model ◽  
Human Arm ◽  
Tension Change

scholarly journals Evaluation of a Bio-impedance Method for Measuring Human Arm Movement

2002 ◽  
Vol 43 (5) ◽  
pp. 637 ◽  
Author(s):  
Jong Chan Kim ◽  
Soo Chan Kim ◽  
Ki Chang Nam ◽  
Seon Hui Ahn ◽  
Mignon Park ◽  
...  
Keyword(s):  
Arm Movement ◽  
Impedance Method ◽  
Human Arm

Experimental Study and Modeling of Equilibrium Point Trajectory Control in Single and Double-Joint Arm Movements

2009 ◽  
Author(s):  
Kai Chen ◽  
Richard A. Foulds ◽  
Katharine Swift ◽  
Sergei Adamovich
Keyword(s):  
Equilibrium Point ◽  
Time Delays ◽  
Arm Movement ◽  
Neuromuscular Control ◽  
Muscle Stimulation ◽  
Time Varying ◽  
Shoulder Joints ◽  
Human Arm ◽  
Neural Transmission ◽  
Human Joint

This paper discusses a new model of neuromuscular control of elbow and shoulder joints based on the Equilibrium Point Hypothesis (EPH). The earlier model [1] suggests that the incorporation of relative damping within reflex loops can maintain the dynamic simplicity of the EPH, while being robust over the range of human joint velocities. The model presented here, extends previous work with the use of experimental Electromyography data of 2 muscles to determine the timing parameters of the virtual trajectories and the inclusion of physiological time delays to account for neural transmission and muscle stimulation/activation delays. This model uses delays presented in the literature by other researchers, with a goal of contributing to a resolution of arguments regarding the controversial arguments in the planning sequences. Therefore, this study attempts to demonstrate the possibility for using descending CNS signals to represent relatively simple, monotonic virtual trajectories of the time varying Equilibrium Point for the control of human arm movement. In addition, the study demonstrates that these virtual trajectories were robust enough to control and coordinated movement of elbow and shoulder joints discussed.

Directional Control of Planar Human Arm Movement

1997 ◽  
Vol 78 (6) ◽  
pp. 2985-2998 ◽  
Author(s):  
Gerald L. Gottlieb ◽  
Qilai Song ◽  
Gil L. Almeida ◽  
Di-An Hong ◽  
Daniel Corcos
Keyword(s):  
Control System ◽  
Arm Movement ◽  
Initial Position ◽  
Joint Torque ◽  
Reaching Movements ◽  
Rule Based ◽  
Joint Torques ◽  
Directional Control ◽  
Human Arm ◽  
Dynamic Components

Gottlieb, Gerald L., Qilai Song, Gil L. Almeida, Di-an Hong, and Daniel Corcos. Directional control of planar human arm movement. J. Neurophysiol. 78: 2985–2998, 1997. We examined the patterns of joint kinematics and torques in two kinds of sagittal plane reaching movements. One consisted of movements from a fixed initial position with the arm partially outstretched, to different targets, equidistant from the initial position and located according to the hours of a clock. The other series added movements from different initial positions and directions and >40–80 cm distances. Dynamic muscle torque was calculated by inverse dynamic equations with the gravitational components removed. In making movements in almost every direction, the dynamic components of the muscle torques at both the elbow and shoulder were related almost linearly to each other. Both were similarly shaped, biphasic, almost synchronous and symmetrical pulses. These findings are consistent with our previously reported observations, which we termed a linear synergy. The relative scaling of the two joint torques changes continuously and regularly with movement direction. This was confirmed by calculating a vector defined by the dynamic components of the shoulder and elbow torques. The vector rotates smoothly about an ellipse in intrinsic, joint torque space as the direction of hand motion rotates about a circle in extrinsic Cartesian space. This confirms a second implication of linear synergy that the scaling constant between the linearly related joint torques is directionally dependent. Multiple linear regression showed that the torque at each joint scales as a simple linear function of the angular displacement at both joints, in spite of the complex nonlinear dynamics of multijoint movement. The coefficients of this function are independent of the initial arm position and movement distance and are the same for all subjects. This is an unanticipated finding. We discuss these observations in terms of the hypothesis that voluntary, multiple degrees of freedom, rapid reaching movements may use rule-based, feed-forward control of dynamic joint torque. Rule-based control of joint torque with separate dynamic and static controllers is an alternative to models such as those based on the equilibrium point hypotheses that rely on a positionally based controller to produce both dynamic and static torque components. It is also an alternative to feed-forward models that directly solve the problems of inverse dynamics. Our experimental findings are not necessarily incompatible with any of the alternative models, but they describe new, additional findings for which we need to account. The rules are chosen by the nervous system according to features of the kinematic task to couple muscle contraction at the shoulder and elbow in a linear synergy. Speed and load control preserves the relative magnitudes of the dynamic torques while directional control is accomplished by modulating them in a differential manner. This control system operates in parallel with a positional control system that solves the problems of postural stability.

Are Complex Control Signals Required for Human Arm Movement?

1998 ◽  
Vol 79 (3) ◽  
pp. 1409-1424 ◽  
Author(s):  
Paul L. Gribble ◽  
David J. Ostry ◽  
Vittorio Sanguineti ◽  
Rafael Laboissière
Keyword(s):  
Joint Stiffness ◽  
Arm Movement ◽  
Movement Speed ◽  
Muscle Properties ◽  
Complex Control ◽  
Equilibrium Trajectory ◽  
Control Signals ◽  
Human Arm ◽  
Constant Rate ◽  
Arm Motion

Gribble, Paul L., David J. Ostry, Vittorio Sanguineti, and Rafael Laboissière. Are complex control signals required for human arm movement? J. Neurophysiol. 79: 1409–1424, 1998. It has been proposed that the control signals underlying voluntary human arm movement have a “complex” nonmonotonic time-varying form, and a number of empirical findings have been offered in support of this idea. In this paper, we address three such findings using a model of two-joint arm motion based on the λ version of the equilibrium-point hypothesis. The model includes six one- and two-joint muscles, reflexes, modeled control signals, muscle properties, and limb dynamics. First, we address the claim that “complex” equilibrium trajectories are required to account for nonmonotonic joint impedance patterns observed during multijoint movement. Using constant-rate shifts in the neurally specified equilibrium of the limb and constant cocontraction commands, we obtain patterns of predicted joint stiffness during simulated multijoint movements that match the nonmonotonic patterns reported empirically. We then use the algorithm proposed by Gomi and Kawato to compute a hypothetical equilibrium trajectory from simulated stiffness, viscosity, and limb kinematics. Like that reported by Gomi and Kawato, the resulting trajectory was nonmonotonic, first leading then lagging the position of the limb. Second, we address the claim that high levels of stiffness are required to generate rapid single-joint movements when simple equilibrium shifts are used. We compare empirical measurements of stiffness during rapid single-joint movements with the predicted stiffness of movements generated using constant-rate equilibrium shifts and constant cocontraction commands. Single-joint movements are simulated at a number of speeds, and the procedure used by Bennett to estimate stiffness is followed. We show that when the magnitude of the cocontraction command is scaled in proportion to movement speed, simulated joint stiffness varies with movement speed in a manner comparable with that reported by Bennett. Third, we address the related claim that nonmonotonic equilibrium shifts are required to generate rapid single-joint movements. Using constant-rate equilibrium shifts and constant cocontraction commands, rapid single-joint movements are simulated in the presence of external torques. We use the procedure reported by Latash and Gottlieb to compute hypothetical equilibrium trajectories from simulated torque and angle measurements during movement. As in Latash and Gottlieb, a nonmonotonic function is obtained even though the control signals used in the simulations are constant-rate changes in the equilibrium position of the limb. Differences between the “simple” equilibrium trajectory proposed in the present paper and those that are derived from the procedures used by Gomi and Kawato and Latash and Gottlieb arise from their use of simplified models of force generation.

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