Pan Zhujun, Van Gemmert Arend W A
a Department of Kinesiology , Mississippi State University , Starkville , MS , USA.
b Fine Motor Control and Learning Laboratory, School of Kinesiology , Louisiana State University , Baton Rouge , LA , USA.
Laterality. 2016;21(3):255-66. doi: 10.1080/1357650X.2015.1134563. Epub 2016 Feb 8.
Asymmetry of inter-limb transfer has been associated with the specialization of the dominant and non-dominant motor system. Reductions of asymmetry have been interpreted as behavioural evidence showing a decline of hemispheric lateralization. A previous study showed that ageing did not qualitatively change the inter-limb transfer asymmetry of a visuo-motor task. The current study elaborates on these findings; it examines whether diminished somatosensory information as a result of peripheral neuropathy (PN) adversely affects inter-limb transfer asymmetry. Twenty individuals affected by PN and 20 older controls were recruited and divided equally across two groups. One group trained a visuo-motor task with the right hand while the other group trained it with the left hand. Performance (initial direction error) of the untrained hand before and after training was collected to determine learning effects from inter-limb transfer. Similar to previous studies, the current study showed asymmetric inter-limb transfer in older controls. In contrast, PN showed inter-limb transfer in both directions indicating that PN reduces inter-limb transfer asymmetry. Increased bilateral hemispheric recruitment is suggested to be responsible for this reduced asymmetry which may compensate for deteriorated tactile and/or proprioceptive inputs in PN. Two possible hypotheses are discussed explaining the relationship between declined somatosensory information and increases in bilateral hemispheric recruitment.
肢体间转移的不对称性与优势和非优势运动系统的专业化有关。不对称性的降低被解释为显示半球侧化下降的行为证据。先前的一项研究表明，衰老并没有在质上改变视觉运动任务中肢体间转移的不对称性。当前的研究详细阐述了这些发现；它研究了由于周围神经病变（PN）导致的体感信息减少是否会对肢体间转移不对称性产生不利影响。招募了20名受PN影响的个体和20名老年对照组，并将他们平均分为两组。一组用右手训练视觉运动任务，而另一组用左手训练。收集训练前后未训练手的表现（初始方向误差），以确定肢体间转移的学习效果。与先前的研究相似，当前的研究在老年对照组中显示出不对称的肢体间转移。相比之下，PN在两个方向上都显示出肢体间转移，表明PN减少了肢体间转移的不对称性。双侧半球募集增加被认为是这种不对称性降低的原因，这可能补偿了PN中触觉和/或本体感觉输入的恶化。讨论了两个可能的假设来解释体感信息下降与双侧半球募集增加之间的关系。
