Timing and visual feedback constraints on repetitive finger force production

We explored predictions of a scheme that views position and force perception as a result of measuring proprioceptive signals within a reference frame set by ongoing efferent process. In particular, this hypothesis predicts force illusions caused by muscle vibration and mediated via changes in both afferent and efferent components of kinesthesia. Healthy subjects performed accurate steady force production tasks by pressing with the four fingers of one hand (the task hand) on individual force sensors with and without visual feedback. At various times during the trials, subjects matched the perceived force using the other hand. High-frequency vibration was applied to one or both of the forearms (over the hand and finger extensors). Without visual feedback, subjects showed a drop in the task hand force, which was significantly smaller under the vibration of that forearm. Force production by the matching hand was consistently higher than that of the task hand. Vibrating one of the forearms affected the matching hand in a manner consistent with the perception of higher magnitude of force produced by the vibrated hand. The findings were consistent between the dominant and nondominant hands. The effects of vibration on both force drift and force mismatching suggest that vibration led to shifts in both signals from proprioceptors and the efferent component of perception, the referent coordinate and/or coactivation command. The observations fit the hypothesis on combined perception of kinematic-kinetic variables with little specificity of different groups of peripheral receptors that all contribute to perception of forces and coordinates. NEW & NOTEWORTHY We show that vibration of hand/finger extensors produces consistent errors in finger force perception. Without visual feedback, finger force drifted to lower values without a drift in the matching force produced by the other hand; hand extensor vibration led to smaller finger force drift. The findings fit the scheme with combined perception of kinematic-kinetic variables and suggest that vibration leads to consistent shifts of the referent coordinate and, possibly, of coactivation command to the effector.

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Role of post-trial visual feedback on unintentional force drift during isometric finger force production tasks

10.1101/864413 ◽

2019 ◽

Author(s):

S Balamurugan ◽

Dhanush Rachaveti ◽

Varadhan SKM

Keyword(s):

Visual Feedback ◽

Visual Information ◽

Force Production ◽

Finger Force ◽

Visual Occlusion ◽

Referent Configuration ◽

Central Controller ◽

Post Trial ◽

Lower Magnitude ◽

The Right

AbstractForce produced during an isometric finger force production task tends to drift towards a lower magnitude when visual information is occluded. This phenomenon of drift in force without one’s awareness is called unintentional drift. The present study used epilogue, a particular case of post-trial visual feedback, and compared the unintentional drift for two conditions, i.e., with and without the epilogue. For this purpose, fourteen healthy participants were recruited for the experiments and were instructed to produce fingertip forces using four fingers of the right hand with the target line at 15% MVC. A trial lasted for sixteen seconds, where for the initial eight seconds, there is visual feedback followed by the visual occlusion period. The results showed a significant reduction in unintentional drift for the condition involving epilogue when compared to no epilogue. This reduction in drift is due to the shift in the referent configuration parameter by the phenomenon of RC back coupling. Further, we also claim that there might be a distribution of λs or RCs, based on the history of tuning of the control parameter by the central controller. This distribution of λs selected by the central controller in a redundant environment based on the epilogue resulted in a reduction of unintentional drift.

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Aging differentially affects online control and offline control in finger force production

PLoS ONE ◽

10.1371/journal.pone.0198084 ◽

2018 ◽

Vol 13 (5) ◽

pp. e0198084

Author(s):

Yang Sun Park ◽

Kyung Koh ◽

Hyun Joon Kwon ◽

Okjin Lee ◽

Jae Kun Shim

Keyword(s):

Force Production ◽

Online Control ◽

Finger Force

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Intermittency in the Control of Continuous Force Production

Journal of Neurophysiology ◽

10.1152/jn.2000.84.4.1708 ◽

2000 ◽

Vol 84 (4) ◽

pp. 1708-1718 ◽

Cited By ~ 203

Author(s):

Andrew B. Slifkin ◽

David E. Vaillancourt ◽

Karl M. Newell

Keyword(s):

Visual Feedback ◽

Visual Information ◽

Spectral Power ◽

Force Production ◽

Motor Output ◽

Force Variability ◽

Force Output ◽

Feedback Information ◽

Information Processes ◽

Feedback Frequency

The purpose of the current investigation was to examine the influence of intermittency in visual information processes on intermittency in the control continuous force production. Adult human participants were required to maintain force at, and minimize variability around, a force target over an extended duration (15 s), while the intermittency of on-line visual feedback presentation was varied across conditions. This was accomplished by varying the frequency of successive force-feedback deliveries presented on a video display. As a function of a 128-fold increase in feedback frequency (0.2 to 25.6 Hz), performance quality improved according to hyperbolic functions (e.g., force variability decayed), reaching asymptotic values near the 6.4-Hz feedback frequency level. Thus, the briefest interval over which visual information could be integrated and used to correct errors in motor output was approximately 150 ms. The observed reductions in force variability were correlated with parallel declines in spectral power at about 1 Hz in the frequency profile of force output. In contrast, power at higher frequencies in the force output spectrum were uncorrelated with increases in feedback frequency. Thus, there was a considerable lag between the generation of motor output corrections (1 Hz) and the processing of visual feedback information (6.4 Hz). To reconcile these differences in visual and motor processing times, we proposed a model where error information is accumulated by visual information processes at a maximum frequency of 6.4 per second, and the motor system generates a correction on the basis of the accumulated information at the end of each 1-s interval.

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The effects of stroke and age on finger interaction in multi-finger force production tasks

Clinical Neurophysiology ◽

10.1016/s1388-2457(03)00164-0 ◽

2003 ◽

Vol 114 (9) ◽

pp. 1646-1655 ◽

Cited By ~ 51

Author(s):

Sheng Li ◽

Mark L Latash ◽

Guang H Yue ◽

Vlodek Siemionow ◽

Vinod Sahgal

Keyword(s):

Force Production ◽

Finger Force

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Do Synergies Improve Accuracy? A Study of Speed-Accuracy Trade-Offs during Finger Force Production

Motor Control ◽

10.1123/mcj.12.2.151 ◽

2008 ◽

Vol 12 (2) ◽

pp. 151-172 ◽

Cited By ~ 28

Author(s):

Stacey L. Gorniak ◽

Marcos Duarte ◽

Mark L. Latash

Keyword(s):

Force Production ◽

Finger Force ◽

Trade Offs ◽

Improve Accuracy ◽

Speed Accuracy

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On the origin of finger enslaving: control with referent coordinates and effects of visual feedback

Journal of Neurophysiology ◽

10.1152/jn.00322.2020 ◽

2020 ◽

Vol 124 (6) ◽

pp. 1625-1636 ◽

Cited By ~ 1

Author(s):

Valters Abolins ◽

Alex Stremoukhov ◽

Caroline Walter ◽

Mark L. Latash

Keyword(s):

Visual Feedback ◽

Force Production ◽

Slow Increase ◽

Cortical Excitation

We report a consistent slow increase in finger enslaving (force production by noninstructed fingers) when visual feedback was presented on the force produced by either two instructed fingers or two noninstructed fingers of the hand. In contrast, force drifts could be in opposite directions depending on the visual feedback. We interpret enslaving and its drifts at the level of control with referent coordinates for the involved muscles, possibly reflecting spread of cortical excitation.

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