Journal article
Recent History of Effector Use Modulates Practice-Dependent Changes in Corticospinal Excitability but Not Motor Learning
Brain stimulation, Vol.9(4), pp.584-593
07/2016
DOI: 10.1016/j.brs.2016.03.019
PMID: 27117281
Abstract
The theory of homeostatic metaplasticity has significant implications for human motor cortical plasticity and motor learning. Previous work has shown that the extent of recent effector use before exogenously-induced plasticity can affect the direction, magnitude and variability of aftereffects. However, the impact of recent effector use on motor learning and practice-dependent plasticity is not known.
We hypothesized that reducing effector use for 8 hours via hand/wrist immobilization would facilitate practice-dependent changes in corticospinal excitability and TMS-evoked thumb movement kinematics, while also promoting 24-hour retention of a ballistic motor skill.
Subjects participated in a crossover study involving two conditions. During the immobilization condition, subjects wore a splint that restricted motion of the left hand and thumb for 8 hours. While wearing the splint, subjects were instructed to avoid using their left hand as much as possible. During the control condition, subjects did not wear a splint at any time nor were they instructed to avoid hand use. After either an 8 hour period of immobilization or normal hand use, we collected MEP and TMS-evoked thumb movement recruitment curves, and subjects practiced a ballistic motor skill involving rapid thumb extension. After motor practice, MEP and TMS-evoked thumb movement recruitment curves were re-tested. Retention of the motor skill was tested 30 minutes and 24 hours after motor practice.
Reduced effector use did not impact pre-practice corticospinal excitability but did facilitate practice-dependent changes in corticospinal excitability, and this enhancement was specific to the trained muscle. In contrast, reducing effector use did not affect practice-dependent changes in TMS-evoked thumb movements nor did it promote acquisition or retention of the skill. Finally, we detected some associations between pre-practice excitability levels, plasticity effects and learning effects, but these did not reach our adjusted criterion for significance.
Experimentally enhancing practice-dependent changes in corticospinal excitability is not sufficient to promote learning or memory of a ballistic motor skill.
Details
- Title: Subtitle
- Recent History of Effector Use Modulates Practice-Dependent Changes in Corticospinal Excitability but Not Motor Learning
- Creators
- Sara J Hussain - Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52246, USA. Electronic address: sara-hussain@uiowa.eduWarren G Darling - Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52246, USAKelly J Cole - Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52246, USA
- Resource Type
- Journal article
- Publication Details
- Brain stimulation, Vol.9(4), pp.584-593
- DOI
- 10.1016/j.brs.2016.03.019
- PMID
- 27117281
- NLM abbreviation
- Brain Stimul
- ISSN
- 1935-861X
- eISSN
- 1876-4754
- Publisher
- United States
- Grant note
- name: University of Iowa Graduate and Professional Student Government Research Grant
- Language
- English
- Date published
- 07/2016
- Academic Unit
- Physical Therapy and Rehabilitation Science; Health, Sport, and Human Physiology
- Record Identifier
- 9984002471802771
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