Stride-time variability and sensorimotor cortical activation during walking
Stride-time variability and sensorimotor cortical activation during walking
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DOI：
10.1016/j.neuroimage.2011.08.084
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发表时间：
2012-01-16
期刊：
影响因子：
5.7
通讯作者：
Arpin, David J.
中科院分区：
文献类型：
--
作者：
Kurz, Max J.;Wilson, Tony W.;Arpin, David J.
从同一条腿连续的脚接触之间所花费的时间被称为跨步时间间隔。几项研究表明，步幅时间间隔的变化与步行平衡有关。在这项研究中，功能性近红外光谱（fNIRS）被用来评估是否在内侧感觉运动皮层的激活反映了步幅时间间隔中看到的变化量。13名健康成人（年龄= 23.7 +/- 1.4岁）在可编程跑步机上前后行走。每个行走条件由两个阶段组成，每个阶段由五个交替的静止站立或以0.45 m/s行走的块组成。使用fNIRS系统测量内侧感觉运动皮层的激活，该系统由4 × 4网格的红外光电二极管发射器/检测器对组成。使用国际10/20系统将视电极定位在参与者的头部上，其中Cz位于前两行视电极的中心下方。我们评估了位于辅助运动区、中央前回、中央后回和上级顶叶小叶上方的通道中的含氧血红蛋白（oxyHb）和脱氧血红蛋白（deoxyHb）量的区块变化。在整个实验过程中，使用脚踏开关系统同时测量跨步时间间隔中存在的变化量。我们的研究结果表明，当参与者向后而不是向前行走时，辅助运动区，中央前回和上级顶叶小叶中的oxyHb更大，这表明向后行走对神经系统提出了更多的挑战，因为它控制着步进模式。此外，有一个显着减少的脱氧血红蛋白的量存在于补充运动区，而向后走。与以前的研究一致，我们注意到，与向前行走相比，向后行走时步幅时间间隔的变异性更大。此外，步行时的步幅时间间隔的变化量与中央前回和辅助运动区中发现的最大oxyHb反应呈正相关，这在以前没有被证明。这种神经行为的关系支持的概念，发现在步幅时间间隔的微妙变化部分与处理需求的运动皮层调节的前向时间运动学。(C)2011 Elsevier Inc. All rights reserved.
The time it takes between consecutive foot contacts from the same leg is referred to as the stride-time interval. Several investigations have shown that the variations that are present in the stride time intervals are linked to walking balance. In this study, functional near infrared spectroscopy (fNIRS) was utilized to evaluate whether activation in the medial sensorimotor cortices reflects the amount of variations seen in the stride-time intervals. Thirteen healthy adults (Age = 23.7 +/- 1.4 yrs.) walked forwards and backwards on a programmable treadmill. Each walking condition consisted of two sessions, with each being comprised of five alternating blocks of standing still or walking at 0.45 m/s. Activation in the medial sensorimotor cortices was measured using an fNIRS system, which consisted of a 4 x 4 grid of infrared optode emitter/detector pairs. The optodes were positioned on the participant's head using the International 10/20 system with Cz located beneath the center of the front two rows of optodes. We evaluated the block-wise changes in the amount of oxygenated (oxyHb) and deoxygenated hemoglobin (deoxyHb) in the channels that were located over the supplementary motor area, pre-central gyrus, post-central gyrus and superior parietal lobule. Throughout the experiment, a footswitch system was used to concurrently measure the amount of variation present in the stride-time intervals. Our results showed that oxyHb was greater in the supplementary motor area, pre-central gyrus, and superior parietal lobule when participants walked backwards rather than forwards, which suggests that backward walking presents more of a challenge to the nervous system as it controls the stepping pattern. Additionally, there was a significant decrease in the amount of deoxyHb present in the supplementary motor area while walking backward. Consistent with previous investigations, we noted that the amount of variability present in the stride-time intervals was greater during backward walking compared to forward walking. In addition, the amount of variation in the stride-time intervals while walking forward was positively correlated with the maximum oxyHb response found in the pre-central gyrus and supplementary motor area, which has not been previously shown. This neurobehavioral relationship supports the notion that the subtle variations found in the stride-time intervals are partly associated with processing demands by the motor cortices for regulating the forward temporal kinematics. (C) 2011 Elsevier Inc. All rights reserved.