Department of Kinesiology, University of Maryland, College Park, MD, USA.
Department of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, MD, USA.
Sci Rep. 2018 Sep 12;8(1):13708. doi: 10.1038/s41598-018-31792-w.
When a person plays a musical instrument, sound is produced and the integrated frequency and intensity produced are perceived aurally. The central nervous system (CNS) receives defective afferent signals from auditory systems and delivers imperfect efferent signals to the motor system due to the noise in both systems. However, it is still little known about auditory-motor interactions for successful performance. Here, we investigated auditory-motor interactions as multi-sensory input and multi-motor output system. Subjects performed a constant force production task using four fingers in three different auditory feedback conditions, where either the frequency (F), intensity (I), or both frequency and intensity (FI) of an auditory tone changed with sum of finger forces. Four levels of uncertainty (high, moderate-high, moderate-low, and low) were conditioned by manipulating the feedback gain of the produced force. We observed performance enhancement under the FI condition compared to either F or I alone at moderate-high uncertainty. Interestingly, the performance enhancement was greater than the prediction of the Bayesian model, suggesting super-optimality. We also observed deteriorated synergistic multi-finger interactions as the level of uncertainty increased, suggesting that the CNS responded to increased uncertainty by changing control strategy of multi-finger actions.
当一个人演奏乐器时，会产生声音，并且所产生的综合频率和强度会通过听觉感知到。由于两个系统中都存在噪声，中枢神经系统（CNS）会从听觉系统接收有缺陷的传入信号，并向运动系统发出不完美的传出信号。然而，对于成功的表现，听觉-运动相互作用仍然知之甚少。在这里，我们将听觉-运动相互作用作为多感觉输入和多运动输出系统进行了研究。在三种不同的听觉反馈条件下，受试者使用四个手指执行恒定力产生任务，其中听觉音调的频率（F）、强度（I）或频率和强度（FI）都随手指力的总和而变化。通过操纵产生力的反馈增益，设定了四个不确定性水平（高、中高、中低和低）。与单独的 F 或 I 相比，我们观察到在中高不确定性下 FI 条件下的性能增强。有趣的是，性能增强大于贝叶斯模型的预测，表明存在超优化。随着不确定性水平的增加，我们还观察到协同多手指交互作用的恶化，这表明中枢神经系统通过改变多手指动作的控制策略来应对增加的不确定性。
