Pohja Marjatta, Salenius Stephan
Low Temperature Laboratory, Helsinki University of Technology, Finland.
Neuroreport. 2003 Mar 3;14(3):321-4. doi: 10.1097/00001756-200303030-00005.
We studied the effect of sensory feedback on the oscillatory interaction between activity of the motor cortex and the spinal motoneuron pool during isometric contraction. After inducing ischaemic sensory deafferentation in the upper limb in six subjects, we calculated coherences between simultaneously recorded whole-scalp magnetoencephalographic (MEG) signals and electromyographic (EMG) signals from the first dorsal interosseus muscles. We expected that the dominant frequency of coherence would change if there were interaction through a sensory feedback loop. However, the MEG-EMG coherence frequency did not change significantly during ischaemia. The strength of the coherence was reduced during ischaemia, but returned to the pre-ischaemic level after ischaemia had ended. Reduction of sensory feedback may thus indirectly reduce the amount of corticomuscular coherence, but the lack of change in the dominant coherent frequency suggests that a sensory feedback loop is not essential for the generation of this coherence.
我们研究了在等长收缩过程中，感觉反馈对运动皮层活动与脊髓运动神经元池之间振荡相互作用的影响。在六名受试者的上肢诱发缺血性感觉传入阻滞之后，我们计算了同时记录的全脑头皮脑磁图（MEG）信号与第一背侧骨间肌的肌电图（EMG）信号之间的相干性。我们预期，如果存在通过感觉反馈回路的相互作用，相干性的主导频率将会改变。然而，在缺血期间，MEG-EMG相干频率并未发生显著变化。相干性的强度在缺血期间降低，但在缺血结束后恢复到缺血前水平。因此，感觉反馈的减少可能会间接减少皮质-肌肉相干性的量，但主导相干频率缺乏变化表明感觉反馈回路对于这种相干性的产生并非必不可少。
