Force oscillations underlying precision grip in humans with lesioned corticospinal tracts.

Autor:	Lafe CW; Human Engineering Research Laboratories, VA RR&D Center of Excellence, VA Pittsburgh Healthcare System, Pittsburgh, PA 15206, USA., Liu F; Rehabilitation Neural Engineering Laboratories, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15213, USA., Simpson TW; Rehabilitation Neural Engineering Laboratories, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15213, USA., Moon CH; Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213, USA., Collinger JL; Human Engineering Research Laboratories, VA RR&D Center of Excellence, VA Pittsburgh Healthcare System, Pittsburgh, PA 15206, USA; Rehabilitation Neural Engineering Laboratories, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA., Wittenberg GF; Human Engineering Research Laboratories, VA RR&D Center of Excellence, VA Pittsburgh Healthcare System, Pittsburgh, PA 15206, USA; Rehabilitation Neural Engineering Laboratories, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA., Urbin MA; Human Engineering Research Laboratories, VA RR&D Center of Excellence, VA Pittsburgh Healthcare System, Pittsburgh, PA 15206, USA; Rehabilitation Neural Engineering Laboratories, University of Pittsburgh, Pittsburgh, PA 15213, USA. Electronic address: m.urbin@pitt.edu.
Jazyk:	angličtina
Zdroj:	NeuroImage. Clinical [Neuroimage Clin] 2023; Vol. 38, pp. 103398. Date of Electronic Publication: 2023 Apr 11.
DOI:	10.1016/j.nicl.2023.103398
Abstrakt:	Stability of precision grip depends on the ability to regulate forces applied by the digits. Increased frequency composition and temporal irregularity of oscillations in the force signal are associated with enhanced force stability, which is thought to result from increased voluntary drive along the corticospinal tract (CST). There is limited knowledge of how these oscillations in force output are regulated in the context of dexterous hand movements like precision grip, which are often impaired by CST damage due to stroke. The extent of residual CST volume descending from primary motor cortex may help explain the ability to modulate force oscillations at higher frequencies. Here, stroke survivors with longstanding hand impairment (n = 17) and neurologically-intact controls (n = 14) performed a precision grip task requiring dynamic and isometric muscle contractions to scale and stabilize forces exerted on a sensor by the index finger and thumb. Diffusion spectrum imaging was used to quantify total white matter volume within the residual and intact CSTs of stroke survivors (n = 12) and CSTs of controls (n = 14). White matter volumes within the infarct region and an analogous portion of overlap with the CST, mirrored onto the intact side, were also quantified in stroke survivors. We found reduced ability to stabilize force and more restricted frequency ranges in force oscillations of stroke survivors relative to controls; though, more broadband, irregular output was strongly related to force-stabilizing ability in both groups. The frequency composition and temporal irregularity of force oscillations observed in stroke survivors did not correlate with maximal precision grip force, suggesting that it is not directly related to impaired force-generating capacity. The ratio of residual to intact CST volumes contained within infarct and mirrored compartments was associated with more broadband, irregular force oscillations in stroke survivors. Our findings provide insight into granular aspects of dexterity altered by corticospinal damage and supply preliminary evidence to support that the ability to modulate force oscillations at higher frequencies is explained, at least in part, by residual CST volume in stroke survivors. Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. (Published by Elsevier Inc.)
Databáze:	MEDLINE
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