Discharge rate modulation of trapezius motor units differs for voluntary contractions and instructed muscle rest.
Discharge rate modulation of trapezius motor units differs for voluntary contractions and instructed muscle rest.
复制标题
DOI：
10.1007/s00221-010-2471-4
复制
发表时间：
2011-01
影响因子：
2
通讯作者：
Maluf, Katrina S.
中科院分区：
文献类型：
--
作者：
Stephenson, Jennifer L.;Christou, Evangelos A.;Maluf, Katrina S.
这项研究检查了在低和高社会心理压力条件下，自愿收缩期间和指导休息期间活跃的斜方肌运动单位在呼吸（0-0.5 Hz）和β（16-32 Hz）频率下的放电率调节。在单独的实验中，记录了健康女性在低强度自愿收缩期间和自愿收缩后指导肌肉休息期间斜方肌的单运动单位活动。使用口头数学任务结合社会评价威胁来控制指导肌肉休息期间的社会心理压力水平，这会增加感知焦虑、心率和血压（P≤0.002）。放电率调制通过感兴趣频带内的运动单位放电率曲线的平均功率来量化。在低压力条件下，与随意收缩期间活跃的运动单位相比，在指示休息期间活跃的运动单位在 0-0.5 Hz 时具有更大的功率（P = 0.002），在 16-32 Hz 时具有较低的功率（P = 0.009）。暴露于应激源会增加指示休息期间运动单位的活动量（P = 0.021），但不会改变 0-0.5 Hz（P = 0.391）或 16-32 Hz（P = 0.089）放电速率调制的功率。这些结果表明，与低强度随意收缩期间相比，在指示肌肉休息期间的持续运动单位活动来自β频率输入的贡献较小，而来自呼吸频率输入的贡献较大。此外，在指导休息期间暴露于压力源时运动单位活动的增加并不是由呼吸或β频率输入的变化引起的。
This study examined discharge rate modulation at respiratory (0–0.5 Hz) and beta (16–32 Hz) frequencies in trapezius motor units active during voluntary contractions and during periods of instructed rest under conditions of low and high psychosocial stress. In separate sessions, single motor unit activity was recorded from the trapezius muscle of healthy women during low-intensity voluntary contractions and during periods of instructed muscle rest that followed voluntary contractions. The level of psychosocial stress during periods of instructed muscle rest was manipulated using a verbal math task combined with social evaluative threat which increased perceived anxiety, heart rate, and blood pressure (P ≤ 0.002). Discharge rate modulation was quantified by the mean power of motor unit discharge rate profiles within frequency bands of interest. Under low stress conditions, motor units active during instructed rest had greater power at 0–0.5 Hz (P = 0.002) and less power at 16–32 Hz (P = 0.009) compared to those active during voluntary contraction. Exposure to the stressor increased the amount of motor unit activity during instructed rest (P = 0.021) but did not alter the power of discharge rate modulation at 0–0.5 Hz (P = 0.391) or 16–32 Hz (P = 0.089). These results indicate that sustained motor unit activity during periods of instructed muscle rest has a lesser contribution from inputs at beta frequencies and a greater contribution from inputs at respiratory frequencies than present during low-intensity voluntary contractions. Furthermore, increases in motor unit activity when exposed to stressors during periods of instructed rest are not caused by changes in inputs at respiratory or beta frequencies.
登录
查看更多内容
DOI：
10.1007/s004200050170
发表时间：
1997-06-01
影响因子：
3
作者：
Hagg, GM;Astrom, A
通讯作者：
Astrom, A
影响因子：
14.5
作者：
GANDEVIA, SC;APPLEGATE, C
通讯作者：
APPLEGATE, C
影响因子：
3.4
作者：
Androulidakis, Alexandros G.;Doyle, Louise M. F.;Brown, Peter
通讯作者：
Brown, Peter
影响因子：
3
作者：
Baweja, Harsimran S.;Kennedy, Deanna M.;Christou, Evangelos A.
通讯作者：
Christou, Evangelos A.
影响因子：
2
作者：
Bawa, P;Hamm, JD;Gross, PA
通讯作者：
Gross, PA