Rapid changes in corticospinal excitability during force field adaptation of human walking
Rapid changes in corticospinal excitability during force field adaptation of human walking
复制标题
DOI：
10.1007/s00221-011-2977-4
复制
发表时间：
2012-03-01
影响因子：
2
通讯作者：
Bouyer, L. J.
中科院分区：
文献类型：
--
作者：
Barthelemy, D.;Alain, S.;Bouyer, L. J.
运动肌肉活动的力场适应是研究大脑和脊髓中的运动控制网络以灵活的方式适应环境变化的能力的一种方法。在这里，我们研究皮质脊髓束是否参与这种适应。我们测量了受试者在跑步机行走期间适应施加到踝关节的力场之前、期间和之后，经颅磁刺激 (TMS) 在胫骨前肌 (TA) 肌肉中引起的运动诱发电位 (MEP) 的变化。当力场在步伐周期的摆动阶段辅助背屈时，受试者通过减少 TA EMG 活动来适应。相反，当力场抵抗背屈时，它们增加了 TA EMG 活性。力场移除后，在接下来的 5 分钟步行中，肌电图活动逐渐恢复正常。在步循环的早期摆动阶段引起的 TA MEP 在适应辅助力场期间较小，而在适应阻力力场期间较大。当力场移除 5 分钟后引发时，MEP 恢复到其原始值。 TA MEP 的变化大于背景 TA EMG 活动变化所能解释的变化。这些影响似乎是步行所特有的，因为在静态背屈期间测试坐姿受试者时，没有看到 TA MEP 的类似变化。这些观察结果表明，皮质脊髓束有助于步行适应外力场。
Force field adaptation of locomotor muscle activity is one way of studying the ability of the motor control networks in the brain and spinal cord to adapt in a flexible way to changes in the environment. Here, we investigate whether the corticospinal tract is involved in this adaptation. We measured changes in motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) in the tibialis anterior (TA) muscle before, during, and after subjects adapted to a force field applied to the ankle joint during treadmill walking. When the force field assisted dorsiflexion during the swing phase of the step cycle, subjects adapted by decreasing TA EMG activity. In contrast, when the force field resisted dorsiflexion, they increased TA EMG activity. After the force field was removed, normal EMG activity gradually returned over the next 5 min of walking. TA MEPs elicited in the early swing phase of the step cycle were smaller during adaptation to the assistive force field and larger during adaptation to the resistive force field. When elicited 5 min after the force field was removed, MEPs returned to their original values. The changes in TA MEPs were larger than what could be explained by changes in background TA EMG activity. These effects seemed specific to walking, as similar changes in TA MEP were not seen when seated subjects were tested during static dorsiflexion. These observations suggest that the corticospinal tract contributes to the adaptation of walking to an external force field.