Kindred John H, Kalliokoski Kari K, Bojsen-Møller Jens, Rudroff Thorsten
Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado.
Turku PET Centre, University of Turku and Turku University Hospital Turku, Finland.
Brain Behav. 2015 Apr;5(4):e00319. doi: 10.1002/brb3.319. Epub 2015 Feb 17.
Many studies have shown that a position task is more difficult than a force task although both are performed at a similar net muscle force. Thus, the time to task failure is consistently shown to be briefer during the position task. The contributions of the central nervous system to these two types of fatiguing contractions are not completely understood. The purpose of this pilot study was to examine differences in regional brain activity between force and position tasks using positron emission tomography (PET) with [(18)F]-Fluorodeoxyglucose (FDG).
Two participants performed both a force and position task, separated by 7 days, with the elbow flexor muscles at 15% maximal voluntary contraction force. During both tasks, each participant was injected with ≈ 256 (SD 11) MBq of FDG. Immediately after both tasks PET imaging was performed and images were analyzed to determine FDG uptake within regions of the brain.
FDG uptake was greater in the occipital and temporal cortices of the brain during the position task compared to the force task.
These findings suggest that differences in visual-spatial feedback and processing may play a role in the reduced time to failure of position tasks. Future application of these findings may lead to improved designs of rehabilitative strategies involving different types of visual feedback.
许多研究表明，尽管在相似的净肌肉力量下进行，但位置任务比力量任务更难。因此，在位置任务期间，任务失败的时间一直显示更短。中枢神经系统对这两种类型的疲劳性收缩的贡献尚未完全了解。这项初步研究的目的是使用正电子发射断层扫描（PET）和[（18）F]-氟脱氧葡萄糖（FDG）来检查力量任务和位置任务之间区域脑活动的差异。
两名参与者进行力量任务和位置任务，中间间隔7天，肘部屈肌以最大自主收缩力的15%进行。在两项任务期间，向每位参与者注射约256（标准差11）MBq的FDG。两项任务完成后立即进行PET成像，并分析图像以确定大脑区域内的FDG摄取情况。
与力量任务相比，位置任务期间大脑枕叶和颞叶皮质的FDG摄取更高。
这些发现表明，视觉空间反馈和处理的差异可能在位置任务失败时间缩短中起作用。这些发现的未来应用可能会导致涉及不同类型视觉反馈的康复策略设计得到改进。
