HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 98/6/3230    most recent 00750.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Krutky, M. A. Articles by Perreault, E. J. Search for Related Content PubMed PubMed Citation Articles by Krutky, M. A. Articles by Perreault, E. J.

Motor Cortical Measures of Use-Dependent Plasticity Are Graded From Distal to Proximal in the Human Upper Limb

¹Sensory Motor Performance Program, Rehabilitation Institute of Chicago; and ²Department of Biomedical Engineering and ³Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois

Submitted 6 July 2007; accepted in final form 13 October 2007

In humans, it is well established that practicing simple, repetitive movements with the distal upper limb induces short-term plasticity in the neural pathways that control training. It is unknown how the neural response to similar training at more proximal joints differs. The purpose of this study was to quantify how ballistic training at proximal and distal upper limb joints influences measures of corticomotor plasticity. To accomplish this goal, we had subjects repetitively practice simple movements for 30 min using the index finger, wrist, or elbow. Before and after training, transcranial magnetic stimulation (TMS) was used to activate the corticomotor pathways innervating the trained joint. We assessed the effect of training by quantifying changes in TMS-elicited joint movements and motor-evoked potentials in the training agonists and antagonists. These measures of training-induced neural plasticity were graded from distal to proximal in the upper limb. Training had the greatest immediate effect on the pathways controlling the index finger and this effect decreased for more proximal joints. Our results suggest that the relative sizes and properties of the cortical areas controlling the proximal and distal upper limb influence the effect of training on the corticomotor pathways. These results have implications for how training influences the neural pathways controlling movement in the proximal and distal portions of the human upper limb and the degree to which these effects can be quantified using TMS.