Heinrichs-Graham Elizabeth, Arpin David J, Wilson Tony W
University of Nebraska Medical Center.
J Cogn Neurosci. 2016 Jul;28(7):1039-51. doi: 10.1162/jocn_a_00948. Epub 2016 Mar 11.
In humans, there is a strong beta (15-30 Hz) event-related desynchronization (ERD) that begins before movement, which has been tentatively linked to motor planning operations. The dynamics of this response are strongly modulated by whether a pending movement is cued and the inherent parameters of the cue. However, previous studies have focused on the information content of cues and not on parameters such as the timing of the cue relative to other events. Variations in such timing are critical, as they directly impact the amount of time that participants have to plan pending movements. In this study, participants performed finger-tapping sequences during magnetoencephalography, and we manipulated the amount of time (i.e., "long" vs. "short") between the presentation of the to-be-executed sequence and the cue to initiate the sequence. We found that the beta ERD was stronger immediately after the cue to move in the contralateral postcentral gyrus and bilateral parietal cortices during the short compared with long planning time condition. During movement execution, the beta ERD was stronger in the premotor cortex and the SMA in the short relative to long condition. Finally, peak latency in the SMA significantly correlated with RT, such that the closer the peak beta ERD was to the cue to move, the quicker the participant responded. The results of this study establish that peri-movement beta ERD activity across the cortical motor circuit is highly sensitive to cue-related temporal factors, with a direct link to motor performance.
在人类中，存在一种强烈的β波（15 - 30赫兹）事件相关去同步化（ERD），它在运动开始前就已出现，这一现象初步被认为与运动计划操作有关。这种反应的动态变化受到即将进行的运动是否有提示以及提示的内在参数的强烈调节。然而，以往的研究主要关注提示的信息内容，而未关注诸如提示相对于其他事件的时间等参数。此类时间变化至关重要，因为它们直接影响参与者计划即将进行的运动的时间量。在本研究中，参与者在进行脑磁图检查时执行手指敲击序列，我们操纵了待执行序列呈现与启动该序列的提示之间的时间量（即“长”与“短”）。我们发现，与长计划时间条件相比，在短计划时间条件下，提示对侧中央后回和双侧顶叶皮质中，提示移动后立即出现的β波ERD更强。在运动执行过程中，与长条件相比，短条件下运动前皮质和辅助运动区的β波ERD更强。最后，辅助运动区的峰值潜伏期与反应时间显著相关，即β波ERD峰值越接近提示移动，参与者反应越快。本研究结果表明，皮质运动回路中运动周围的β波ERD活动对与提示相关的时间因素高度敏感，且与运动表现直接相关。
