| 摘要: | Past studies have indicated that physiological signals from internal bodily organs, such as breathing influence diverse perceptual and motor processes. Findings suggest that there is a coupling between the breathing phase and the initiation of voluntary movements, indicating a potential interaction between these two processes. In particular, a recent study revealed that the breathing pattern of participants was synchronized to the onset of their voluntary movements, even though participants had complete freedom to choose when to initiate their movements. Moreover, the study also revealed that there was a coupling between the breathing phase and the amplitude of the readiness potential (RP), a neural signal associated with voluntary action. One proposed explanation of the synchronization between the breathing phase and voluntary action is to avoid potential motor competition. During breathing, there are active and passive phases, where the active phase corresponds to inhalation and the passive phase to exhalation. It has been suggested that participants unconsciously prefer to initiate voluntary actions, such as finger movements, during exhalation. This choice arises from the relatively lower involvement of the brain in monitoring the passive exhalation phase, reducing the potential neural interference between the motor signals related to breathing and voluntary movement. However, another line of research has also looked at the synchronization between motor movement and respiration as a lower-level automatic process. Animal electrophysiological studies have provided evidence that there is a coupling between whisking and sniffing in rodents, though it primarily pertains to involuntary movements. In our study, we investigate the possibility that different types of finger movements (e.g., pressing vs. lifting/ upward vs. downward) might result in a differential pattern of breathing-action coupling. We would like to investigate whether the synchronization between the breathing phase and the voluntary action is taking place to avoid motor competition through an active top-down process involving cortical processing or whether it is primarily driven by a bottom-up automatic process, suggesting the presence of a lower-level built-in mechanism that synchronizes the movements. To assess the potential differences between various types of finger movement and breathing phases, participants performed a modified version of the Libet paradigm and were instructed to initiate four types of finger movements, all in a self-initiated manner, while measuring EEG and respiratory signals: 1) index finger flexion with palm facing downward, 2) index finger extension with palm facing downward, 3) index finger flexion with palm facing upward, 4) index finger extension with palm facing upward. We report that there is a consistent coupling between breathing and voluntary action, regardless of the type of muscle movement or the direction of movement relative to gravity. In addition, we observed readiness potential (RP), across all conditions, indicating a robust relationship between the breathing phase and voluntary action. |
