Neuroscience 2003 Abstract
| Presentation Number: | 392.7 |
|---|---|
| Abstract Title: | Variance of magnetic resonance imaging T2 times among tasks. |
| Authors: |
Giordano, S. B.*1
; Marquardt, K.2,3
; Nelson, N.2,3
; Rush, S.2,3
; Simoneaux, S.4
; Song, A. W.5
; Segal, R. L.1,2,3
1Program in Neurosci., Emory Univ, Atlanta, GA 2GA, Rm 213 Ctr For Rehab Med, 30322, 3USA, Rm 213 Ctr For Rehab Med, 30322, 4Div Physical Therapy, Rm 213 Ctr For Rehab Med, 30322, 5Dept. Rehab. Med., Rm 213 Ctr For Rehab Med, 30322, |
| Primary Theme and Topics |
Motor Systems - Muscle and Motor Unit -- Physiology |
| Secondary Theme and Topics | Motor Systems<br />- Muscle and Motor Unit<br />-- Anatomy |
| Session: |
392. Muscle & Motor Unit: Function Poster |
| Presentation Time: | Monday, November 10, 2003 10:00 AM-11:00 AM |
| Location: | Morial Convention Center - Hall F-I, Board # I28 |
| Keywords: | Muscle, Motor Unit, MRI |
There have been reports in the literature over the past 20 years that some muscles are not homogeneously activated (i.e. activated as subvolumes) during tasks. During the same period of time magnetic resonance (MR) imaging T2 times have started to be used to measure muscle activity. Certain potential subvolume organizations of motor units could lead to greater variability of T2 time as task effort increases (Prior et al., 1999). Prior et al tested the preceding hypothesis, but did not find any statistically significant differences in whole muscle T2 time variance with increased effort although there was a tendency for variance to increase. The purpose of this study was to look for changes in whole muscle T2 time variance in leg muscles including one purportedly compartmentalized muscle, the lateral gastrocnemius (LG; Segal et al., 1991). Able-bodied subjects carried out concentric plantarflexion contractions against loads equal to 25% and 65% of maximal voluntary contraction (MVC). All subjects had pre and post exercise T2 time measurements and pre-exercise T1 sequences of the right leg while secured in an axial multi-element volumetric coil. Preliminary analysis of whole muscle T2 time variance shows no tendency for increased variance with increased effort in any of the muscles including LG. Interestingly, there is a tendency for decreased variation in the peroneal muscles at efforts of 65% of MVC.
Supported by NICHD NCMRR grant HD 32571
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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