Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Clin Neurophysiol. 2010 Mar;121(3):392-401. doi: 10.1016/j.clinph.2009.09.033. Epub 2009 Dec 30.
To propose a model-free method to show linear and nonlinear information flow based on time-delayed mutual information (TDMI) by employing uni- and bi-variate surrogate tests and to investigate whether there are contributions of the nonlinear information flow in corticomuscular (CM) interaction.
Using simulated data, we tested whether our method would successfully detect the direction of information flow and identify a relationship between two simulated time series. As an experimental data application, we applied this method to investigate CM interaction during a right wrist extension task.
Results of simulation tests show that we can correctly detect the direction of information flow and the relationship between two time series without a prior knowledge of the dynamics of their generating systems. As experimental results, we found both linear and nonlinear information flow from contralateral sensorimotor cortex to muscle.
Our method is a viable model-free measure of temporally varying causal interactions that is capable of distinguishing linear and nonlinear information flow. With respect to experimental application, there are both linear and nonlinear information flows in CM interaction from contralateral sensorimotor cortex to muscle, which may reflect the motor command from brain to muscle.
This is the first study to show separate linear and nonlinear information flow in CM interaction.
通过使用单变量和双变量替代检验，提出一种基于时滞互信息（TDMI）的无模型方法来显示线性和非线性信息流，并研究皮质肌肉（CM）相互作用中是否存在非线性信息流的贡献。
使用模拟数据，我们测试了我们的方法是否能够成功检测信息流的方向并识别两个模拟时间序列之间的关系。作为实验数据的应用，我们应用该方法研究了右腕伸展任务期间的 CM 相互作用。
模拟测试的结果表明，我们可以在没有其生成系统动力学先验知识的情况下，正确检测信息流的方向和两个时间序列之间的关系。作为实验结果，我们发现来自对侧感觉运动皮层到肌肉的线性和非线性信息流。
我们的方法是一种可行的、无模型的、随时间变化的因果相互作用的测量方法，能够区分线性和非线性信息流。就实验应用而言，对侧感觉运动皮层到肌肉的 CM 相互作用中存在线性和非线性信息流，这可能反映了大脑到肌肉的运动指令。
这是第一项显示 CM 相互作用中线性和非线性信息流分离的研究。
