Short-latency muscle response patterns to multi-directional, unpredictable perturbations to balance applied to the arm are context dependent

Forghani, Ali; Preuss, Richard; Milner, Theodore E.

doi:10.1016/j.neuroscience.2017.03.062

Cited by 9 publications

(6 citation statements)

References 30 publications

(41 reference statements)

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“…These findings are consistent with the conceptualization of a common central organization between postural adjustments and arm movements (Cordo and Nashner 1982), with reciprocal interplay between the two task components (de Lima et al 2010). Previous research has shown integrative posturo-manual control also in the opposite direction, with predictable (Forghani et al 2017a(Forghani et al , 2017b and unpredictable (Forghani et al 2017a(Forghani et al , 2017bLowrey et al 2017) extrinsic perturbations applied to the arms, as well as self-produced load manipulation (Aruin and Latash 1996;Lee et al 1990) or voluntary arm movements (Lee et al 1987;Mochizuki et al 2004) leading to scaled postural adjustments to prevent body balance instability. As further evidence of integrative control between upper and lower limb movements in dynamic balance, Misiaszek and Krauss (2005) found that restriction of arm movements (by crossing them) while walking, as compared with unconstrained swinging of the arms, induced increased muscular activation of the legs in response to sudden mechanical perturbations applied during locomotion.…”

Section: Discussionsupporting

confidence: 88%

“…In comparison with the larger rectangular target, analysis indicated that when aiming at the smaller circle the final hand positions were less variable and muscular responses in the lower limbs were stronger. The adaptive postural responses to the perturbations produced greater displacements of center of pressure (CoP) under the feet to keep body balance stability, in consonance with the required greater hand trajectory corrections (see also Forghani et al 2017aForghani et al , 2017b. As a whole, results mentioned thus far support the notion of common central organization between postural and arm movements, with the upper and lower limbs being flexibly integrated to attend the constraints imposed by the behavioral goal.…”

Section: Introductionmentioning

confidence: 53%

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Regulation of dynamic postural control to attend manual steadiness constraints

Teixeira

Coutinho

Coelho

2018

Journal of Neurophysiology

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In daily living activities, performance of spatially accurate manual movements in upright stance depends on postural stability. In the present investigation, we aimed to evaluate the effect of the required manual steadiness (task constraint) on the regulation of dynamic postural control. A single group of young participants ( n = 20) were evaluated in the performance of a dual posturo-manual task of balancing on a platform oscillating in sinusoidal translations at 0.4-Hz (low) or 1-Hz (high) frequencies while stabilizing a cylinder on a handheld tray. Manual task constraint was manipulated by comparing the conditions of keeping the cylinder stationary on its flat or round side, corresponding to low and high manual task constraints, respectively. Results showed that in the low oscillation frequency the high manual task constraint led to lower oscillation amplitudes of the head, center of mass, and tray, in addition to higher relative phase values between ankle/hip-shoulder oscillatory rotations and between center of mass/center of pressure-feet oscillations as compared with values observed in the low manual task constraint. Further analyses showed that the high manual task constraint also affected variables related to both postural (increased amplitudes of center of pressure oscillation) and manual (increased amplitude of shoulder rotations) task components in the high oscillation frequency. These results suggest that control of a dynamic posturo-manual task is modulated in distinct parameters to attend the required manual steadiness in a complex and flexible way. NEW & NOTEWORTHY We evaluated dynamic postural control on a platform oscillating in sinusoidal translations at different frequencies while performing a manual task with low or high steadiness constraints. Results showed that high manual task constraint led to modulation of metric and coordination variables associated with greater postural stability. Our findings suggest that motor control is regulated in an integrative mode at the posturo-manual task level, with reciprocal interplay between the postural and manual components.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 53%

Regulation of dynamic postural control to attend manual steadiness constraints

Teixeira

Coutinho

Coelho

2018

Journal of Neurophysiology

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“…However, under flexed and extended elbow conditions the response in ankle muscles occurred at the same latency despite differences in the magnitude and onset of the body segment motion. We had previously shown that stance width also had no effect on the latency [ 11 ]. Thus, we did not find evidence for a mechanical effect on the latency of the response in ankle muscles.…”

Section: Discussionmentioning

confidence: 99%

“…We then varied stance width to test the hypothesis that the response to perturbations to the arm is context dependent, i.e. by altering balance in only the medial/lateral direction we showed that the amplitude of the response was altered only in lower limb muscles and only for the directions in which balance stability had been altered [ 11 ]. In that study, we also showed that the latency difference between the earliest changes in body kinematics and kinetics induced by the perturbation and the response in ankle muscles was not affected by stance width.…”

Section: Introductionmentioning

confidence: 99%

Origin of directionally tuned responses in lower limb muscles to unpredictable upper limb disturbances

Forghani

Milner

2017

PLoS ONE

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Unpredictable forces which perturb balance are frequently applied to the body through interaction between the upper limb and the environment. Lower limb muscles respond rapidly to these postural disturbances in a highly specific manner. We have shown that the muscle activation patterns of lower limb muscles are organized in a direction specific manner which changes with lower limb stability. Ankle muscles change their activity within 80 ms of the onset of a force perturbation applied to the hand which is earlier than the onset of changes in ground reaction force, ankle angle or head motion. The latency of the response is sensitive to the perturbation direction. However, neither the latency nor the magnitude of the response is affected by stiffening the arm even though this alters the magnitude and timing of motion of the body segments. Based on the short latency, insensitivity of the change in ankle muscle activation to motion of the body segments but sensitivity to perturbation direction we reason that changes in ankle muscle activation are most likely triggered by sensory signals originating from cutaneous receptors in the hand. Furthermore, evidence that the latency of changes in ankle muscle activation depends on the number of perturbation directions suggests that the neural pathway is not confined to the spinal cord.

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“…Typically, postural responses can be described using kinetics and/or kinematic means, as well as by the analysis of muscular activity, as detected by electromyography [12]. However, among the several measurements available, the ones related to the displacement of the Center of Pressure, defined as the instantaneous position of the mean of the base of support reactive forces to the subject's weight, are commonly used to analyze postural response both in static and in dynamic condition [5,7,9,[13][14][15][16]. In addition, analyses based on 3-D motion capture are also performed to study the movement of the human body during posture recovery by means of optoelectronic systems [17,18] and inertial measurement units (IMUs) [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Hardware-In-the-Loop Equipment for the Development of an Automatic Perturbator for Clinical Evaluation of Human Balance Control

et al. 2020

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Nowadays, increasing attention is being paid to techniques aimed at assessing a subject’s ability to maintain or regain control of balance, thus reducing the risk of falls. To this end, posturographic analyses are performed in different clinical settings, both in unperturbed and perturbed conditions. This article presents a new Hardware-In-the-Loop (HIL) equipment designed for the development of an automatic perturbator for postural control analysis, capable of providing controlled mechanical stimulation by means of an impulsive force exerted on a given point of the body. The experimental equipment presented here includes the perturbator and emulates its interaction with both the subject’s body and the operator performing the test. The development of the perturbator and of the entire HIL equipment is described, including component selection, modeling of the entire system, and experimentally verified simulations used to study and define the most appropriate control laws.

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Short-latency muscle response patterns to multi-directional, unpredictable perturbations to balance applied to the arm are context dependent

Cited by 9 publications

References 30 publications

Regulation of dynamic postural control to attend manual steadiness constraints

Regulation of dynamic postural control to attend manual steadiness constraints

Origin of directionally tuned responses in lower limb muscles to unpredictable upper limb disturbances

Hardware-In-the-Loop Equipment for the Development of an Automatic Perturbator for Clinical Evaluation of Human Balance Control

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