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

Gollee, H. , Gawthrop, P. J., Lakie, M. and Loram, I. D. (2017) Visuo-manual tracking: does intermittent control with aperiodic sampling explain linear power and non-linear remnant without sensorimotor noise? Journal of Physiology, 595(21), pp. 6751-6770. (doi: 10.1113/JP274288) (PMID:28833126) (PMCID:PMC5663819)

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The 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; 350, 550 ms; 1st 2nd order systems respectively). Our two questions are (i) 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, 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% v. 8–48%, IC v CC). Between conditions, IC used thresholds and distributions of open loop intervals consistent respectively with instructions and previous measured, model independent values; whereas CCN required changes in noise spectrum deviating from broadband, signal dependent noise. We conclude 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 involved in visuomanual tracking.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Gollee, Dr Henrik and Loram, Mr Ian David and Gawthrop, Professor Peter
Authors: Gollee, H., Gawthrop, P. J., Lakie, M., and Loram, I. D.
College/School:College of Science and Engineering
College of Science and Engineering > School of Engineering > Biomedical Engineering
Journal Name:Journal of Physiology
ISSN (Online):1469-7793
Published Online:21 August 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Journal of Physiology 595(21): 6751-6770
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
476761Intermittent predictive control of man and machineHenrik GolleeEngineering and Physical Sciences Research Council (EPSRC)EP/F069022/1ENG - BIOMEDICAL ENGINEERING