Variability in Motor Output As Noise: A Default and Erroneous Proposition?

Newell, Karl M.; Deutsch, Katherine M.; Sosnoff, Jacob J.; Mayer‐Kress, Gottfried

doi:10.5040/9781492596851.ch-001

Cited by 36 publications

(40 citation statements)

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“…) and approximates typically a ‘1/ f ’ power law spanning the muscle bandwidth (0–20 Hz) (Newell et al . ). This ‘motor noise’ arises from the orderly recruitment and firing rate variability within the motor neuron pool innervating muscles (Jones et al .…”

Section: Discussionmentioning

confidence: 97%

“…Broadband random noise is associated with all biological processes (Newell et al . ). These noise sources are assumed to arise from basic physiological sensory and motor processes.…”

Section: Introductionmentioning

confidence: 97%

“…We acknowledge that many authors have considered additive and state‐dependent noise, the interaction of noise with complex systems and the interaction of noise with thresholds (Harris & Wolpert, ; Beggs & Plenz, ; Newell et al . ; Gold & Shadlen, ; Patzelt et al . ; Beck et al .…”

Section: Introductionmentioning

confidence: 99%

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Visuo‐manual tracking: does intermittent control with aperiodic sampling explain linear power and non‐linear remnant without sensorimotor noise?

Gollee

Gawthrop

Lakie

et al. 2017

The Journal of Physiology

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Key points A human controlling an external system is described most easily and conventionally as linearly and continuously translating sensory input to motor output, with the inevitable output remnant, non‐linearly related to the input, attributed to sensorimotor noise.Recent experiments show sustained manual tracking involves repeated refractoriness (insensitivity to sensory information for a certain duration), with the temporary 200–500 ms periods of irresponsiveness to sensory input making the control process intrinsically non‐linear.This evidence calls for re‐examination of the extent to which random sensorimotor noise is required to explain the non‐linear remnant.This investigation of manual tracking shows how the full motor output (linear component and remnant) can be explained mechanistically by aperiodic sampling triggered by prediction error thresholds.Whereas broadband physiological noise is general to all processes, aperiodic sampling is associated with sensorimotor decision making within specific frontal, striatal and parietal networks; we conclude that manual tracking utilises such slow serial decision making pathways up to several times per second. AbstractThe human operator is described adequately by linear translation of sensory input to motor output. Motor output also always includes a non‐linear remnant resulting from random sensorimotor noise from multiple sources, and non‐linear input transformations, for example thresholds or refractory periods. Recent evidence showed that manual tracking incurs substantial, serial, refractoriness (insensitivity to sensory information of 350 and 550 ms for 1st and 2nd order systems respectively). Our two questions are: (i) What are the comparative merits of explaining the non‐linear remnant using noise or non‐linear transformations? (ii) Can non‐linear transformations represent serial motor decision making within the sensorimotor feedback loop intrinsic to tracking? Twelve participants (instructed to act in three prescribed ways) manually controlled two systems (1st and 2nd order) subject to a periodic multi‐sine disturbance. Joystick power was analysed using three models, continuous‐linear‐control (CC), continuous‐linear‐control with calculated noise spectrum (CCN), and intermittent control with aperiodic sampling triggered by prediction error thresholds (IC). Unlike the linear mechanism, the intermittent control mechanism explained the majority of total power (linear and remnant) (77–87% vs. 8–48%, IC vs. CC). Between conditions, IC used thresholds and distributions of open loop intervals consistent with, respectively, instructions and previous measured, model independent values; whereas CCN required changes in noise spectrum deviating from broadband, signal dependent noise. We conclude that manual tracking uses open loop predictive control with aperiodic sampling. Because aperiodic sampling is inherent to serial decision making within previously identified, specific frontal, striatal and parietal networks we suggest that these structures are intimately inv...

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Section: Discussionmentioning

confidence: 97%

“…Broadband random noise is associated with all biological processes (Newell et al . ). These noise sources are assumed to arise from basic physiological sensory and motor processes.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Visuo‐manual tracking: does intermittent control with aperiodic sampling explain linear power and non‐linear remnant without sensorimotor noise?

Gollee

Gawthrop

Lakie

et al. 2017

The Journal of Physiology

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“…Motor variability (MV) is inherently present throughout the multiple levels of movement organisation and occurs not only between but even within individuals (e.g. Newell, Deutsch, Sosnoff, & Mayer-Kress, 2006; Bartlett, Wheat, & Robins, 2007;Preatoni, Squadrone, & Rodano, 2005;Preatoni, 2007). MV results from the extreme complexity of the neuro-musculo-skeletal system and of the redundancy of its degrees of freedom.…”

Section: Introductionmentioning

confidence: 99%

Motor variability in sports: A non-linear analysis of race walking

Preatoni

Ferrario

Doná

et al. 2010

Journal of Sports Sciences

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This aim of this study was to analyse the nature of movement variability and to assess whether entropy measures may represent a valuable synthetic index of neuromuscular organization. The regularity of kinematic/kinetic time series during race walking, the changes in the structure of intra-individual variability over the test session, and the influence of athletic skill in (inter)national rank athletes were investigated. Motion analysis techniques were used. Sample entropy (SampEn) was adopted to examine fluctuations in lower limb angles and ground reaction forces. The regularity of both original and surrogate time series was assessed and compared, by estimating SampEn, to verify the presence of non-linear features in movement variability. SampEn was statistically lower in the original data than in surrogates. In contrast, the regularity of time series did not change significantly throughout the subsequent intra-individual repetitions. Hip and ankle joint angles and vertical ground reaction force manifested increased entropy for skilled athletes. Results suggest that race walking variability was not only the product of random noise but also contained information about the inherent propriety of the neuro-musculo-skeletal system. Furthermore, they provide some indications about neuromuscular control of the lower limb joints during race walking gait, and about the differences between more and less skilled individuals.

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“…While this is currently the prominent model in human control, its physiological basis is not fully established. This has led to the idea that the remnant signal might be based on structure rather than randomness (Newell, Deutch, Sosnoff, and Mayer-Kress, 2006).…”

Section: Intermittent Control In Man and Machine Peter Gawthrop Henrmentioning

confidence: 99%

Intermittent Control in Man and Machine

Gawthrop¹,

Gollee²,

Loram³

2018

Event-Based Control and Signal Processing

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Intermittent control has a long history in the physiological literature and there is strong experimental evidence that some human control systems are intermittent. Intermittent control has also appeared in various forms in the engineering literature. This article discusses a particular mathematical model of Event-driven Intermittent Control which brings together engineering and physiological insights and builds on and extends previous work in this area. Illustrative examples of the properties of Intermittent Control in a physiological context are given together with suggestions for future research directions in both physiology and engineering. i arXiv:1407.3543v1 [q-bio.QM]

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Variability in Motor Output As Noise: A Default and Erroneous Proposition?

Cited by 36 publications

References 0 publications

Visuo‐manual tracking: does intermittent control with aperiodic sampling explain linear power and non‐linear remnant without sensorimotor noise?

Visuo‐manual tracking: does intermittent control with aperiodic sampling explain linear power and non‐linear remnant without sensorimotor noise?

Motor variability in sports: A non-linear analysis of race walking

Intermittent Control in Man and Machine

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