School of Electrical and Computer Engineering, Georgia Institute of Technology, 555 14th St., Atlanta, GA 30332-0356, USA.
J Appl Physiol (1985). 2012 Mar;112(6):970-81. doi: 10.1152/japplphysiol.01079.2011. Epub 2012 Jan 5.
Aging and dual-task paradigms often degrade fine motor performance, but the effects of aging on correlated neural activity between motor cortex and contracting muscle are unknown during dual tasks requiring fine motor performance. The purpose of this study was to compare corticomuscular coherence between young and elderly adults during the performance of a unilateral fine motor task and concurrent motor and cognitive tasks. Twenty-nine healthy young (18-38 yr) and elderly (61-75 yr) adults performed unilateral motor, bilateral motor, concurrent motor-cognitive, and cognitive tasks. Peak corticomuscular coherence between the electroencephalogram from the primary motor cortex and surface electromyogram from the first dorsal interosseous muscle was compared during steady abduction of the index finger with visual feedback. In the alpha-band (8-14 Hz), corticomuscular coherence was greater in elderly than young adults especially during the motor-cognitive task. The beta-band (15-32 Hz) corticomuscular coherence was higher in elderly than young adults across unilateral motor and dual tasks. In addition, beta-band corticomuscular coherence in the motor-cognitive task was negatively correlated with motor output error across young but not elderly adults. The results suggest that 1) corticomuscular coherence was increased in senior age with a greater influence of an additional cognitive task in the alpha-band and 2) individuals with greater beta-band corticomuscular coherence may exhibit more accurate motor output in young, but not elderly adults, during steady contraction with visual feedback.
衰老和双重任务范式通常会降低精细运动表现，但在需要精细运动表现的双重任务中，衰老对运动皮层和收缩肌肉之间相关神经活动的影响尚不清楚。本研究旨在比较年轻和老年成年人在执行单侧精细运动任务和同时进行运动和认知任务时运动皮层和收缩肌肉之间的皮质肌相干性。29 名健康的年轻（18-38 岁）和老年（61-75 岁）成年人执行了单侧运动、双侧运动、同时运动认知和认知任务。在视觉反馈下，用食指进行稳定外展时，比较脑电图（EEG）来自运动皮层和表面肌电图（sEMG）来自第一背侧骨间肌的峰皮质肌相干性。在 alpha 波段（8-14 Hz），皮质肌相干性在老年人中高于年轻人，尤其是在运动认知任务中。在单侧运动和双重任务中，beta 波段（15-32 Hz）皮质肌相干性在老年人中高于年轻人。此外，运动认知任务中的 beta 波段皮质肌相干性与年轻人的运动输出误差呈负相关，但与老年人无关。结果表明：1）皮质肌相干性在老年中增加，在 alpha 波段，额外的认知任务影响更大；2）在有视觉反馈的稳定收缩中，具有更大 beta 波段皮质肌相干性的个体可能在年轻人中表现出更准确的运动输出，但在老年人中则不然。
