认知与发展心理学研究室知识库

心智游移是指注意从关注当前任务转移到关注内部的与当前任务无关的思维。许多研究已经发现心智游移会干扰运动行为，但是这些研究多是在行为层面探讨，心智游移影响运动控制的神经机制尚不清楚。根据运动表现的 OPTIMAL 理论，注意和动机因素会影响运动表现。解耦假说认为心智游移是一个注意和外部环境解耦的状态，会和当前任务竞争有限的执行控制资源，因此注意的脱离是心智游移影响运动控制的重要原因。持续注意的资源控制理论认为心智游移的发生是由于对当前任务保持注意的动机或努力下降，因此心智游移可能导致对外部环境的反应动机下降。在不同难度的任务中心智游移的特点不同，尚不清楚任务难度是否以及如何调节心智游移对运动控制的影响。本论文采用高时间分辨率的 EEG 技术从时间动态的角度探讨心智游移影响运动控制的神经机制，主要考察运动意图，运动准备和运动执行三个方面，并进一步探讨任务难度对心智游移影 响运动控制的调节作用。

研究一采用 EEG 技术方法，从时间动态特征的角度探讨心智游移影响运动 控制的神经机制。实验 1 中要求右利手被试使用左右手食指根据信号做按键和抬 键动作，采用左右手食指做动作的目的是利用利手性操纵动作难度，一个完整的动作包括一个按键和一个抬键动作。结果发现心智游移会导致反应速度变慢，反 应变异性增大。左右食指按键的反应速度没有观测到显著差异，但右手食指抬键 显著快于左手食指。在运动意图方面，心智游移衰减按键动作前的 200 毫秒范围内的 NS’脑电成分。在运动准备方面，心智游移降低了左手动作的-800 到-200 毫秒范围内的 LRP 成分，说明心智游移对运动准备的影响受利手性的调节。在运动执行阶段，心智游移降低了按键动作前后 100 毫秒范围内的与运动控制相关的前额 delta-theta（1-7 Hz）神经振荡活动及反应手对侧大脑区域 delta-theta 功能连接。对于抬键，右手食指抬键动作诱发了比左手食指抬键更强的反应手对侧 delta-theta 功能连接，并且心智游移只降低了右手抬键的反应手对侧 delta-theta 功能连接以及前额 delta-theta 神经振荡活动，而不影响左手抬键，这可能反映了动作难度调节心智游移对运动控制的影响。此外，我们在实验 1 中考察了心智游移对 EEG 非周期信号成分的影响，结果发现心智游移会导致非周期信号成分的斜率和截距变大。

研究二探讨动作难度对心智游移影响运动控制的调节作用，以及对比心智游移对运动控制的“内源性干扰”和工作记忆任务对运动控制的“外源性干扰”的异同点。实验 2 系统操纵了信号反应任务中反应方式的动作难度，在正式实验之前，首先测量了右手单个手指按键和抬键的反应速度，并进一步设计了双指动作，确定了右手食指加中指（RIM）为相对简单的双指动作类型，右手食指加无名指（RIR）为相对困难的双指动作类型。同样，正式实验的反应时结果发现 RIM 按 键比 RIR 按键速度更快，但在抬键动作中没有观测到显著差异。在运动执行阶段，RIM 按键诱发的前额 delta-theta 活动显著大于 RIR 按键，并且心智游移只衰 减了RIM 按键的前额 delta-theta 活动，而不影响 RIR 按键，这说明动作难度调 节了心智游移对运动控制的影响。在实验 2 中，我们重复了实验 1 中发现的心智 游移导致非周期信号成分的斜率和截距变大，说明非周期信号成分可以作为心智 游移更稳定的生物标记物。为了和实验 2 进行对比，实验 3 采用双任务范式，主任务为动作反应，第二任务为工作记忆信息维持任务。结果发现与心智游移不同的是，工作记忆信息维持会增强运动意图；与心智游移相同的是，在运动执行阶段，工作记忆信息维持只降低简单动作的前额 delta-theta 活动。

研究三探讨背景任务难度对心智游移影响运动控制的调节作用。实验 2 只操纵了运动反应阶段的难度，实验 4 则操纵感觉和认知加工阶段的难度，采用词频操纵词义加工难度，要求被试在持续注意反应任务 SART 中执行词义判断任务。低频词汇对应困难任务条件，高频词汇对应简单任务条件，反应时的结果发现对高频词汇的反应速度显著快于低频词汇。实验 4 主要发现了心智游移只衰减了高 频词汇条件中的前额 delta-theta 活动，而不影响低频词汇条件。实验 4 证明了背景任务难度也会调节心智游移对运动控制的影响。 本研究利用高时间分辨率的 EEG 技术，从时间动态特征的角度，详细考察了心智游移影响运动控制的神经机制，促进了对心智游移这个复杂现象的理解。

本研究还揭示了任务难度会调节心智游移对运动控制的影响，解耦假说的主要观点是执行资源的总量有限，那么应该是越困难的任务受心智游移的影响越大。但是，如果考虑为任务调用的执行资源数量可变，根据执行控制失败假说，简单任务需要较低的控制水平，因此可能为任务招募的总执行资源数量较少；而根据持续注意的资源控制理论，简单任务需要的努力程度较低，更容易导致对任务保持注意的动机下降，使得执行资源更偏向于分配给心智游移，而困难任务则相反。因此，反而是简单任务更容易受到心智游移的影响。本论文的研究发现说明心智游移和运动控制对执行资源的竞争和占用方式依赖于任务环境，进一步整合并完善了心智游移的相关理论假说。

Mind wandering refers to the shifting of attention from the current task to task-unrelated thoughts internally. Many studies have found that mind wandering can disrupt motor behavior, but these studies mainly explore it at the behavioral level, and the neural mechanisms underlying the influence of mind wandering on motor control are not yet clear. According to the OPTIMAL theory of motor performance, attention and motivational factors can affect motor performance. The decoupling hypothesis suggests that mind wandering is a state of decoupling attention from the external environment, competing with limited executive control resources for the current task, thus the disengagement of attention is an important reason for the impact of mind wandering on motor control. The sustained attentional resource control theory suggests that mind wandering occurs due to a decrease in motivation or effort to maintain attention on the current task, which may lead to a decrease in motivation to react to the external environment. The characteristics of mind wandering vary in tasks of different difficulties, and it is unclear whether and how task difficulty modulates the impact of mind wandering on motor control. This paper used high-temporal-resolution EEG technology to explore the neural mechanisms underlying the influence of mind wandering on motor control from a temporal dynamic perspective, mainly focusing on motor intention, motor preparation, and motor execution, and further investigates the modulatory effect of task difficulty on the impact of mind wandering on motor control.

Study 1 employed EEG technology to explore the neural mechanisms underlying the influence of mind wandering on motor control from the perspective of temporal dynamics. In Experiment 1, right-handed participants were required to perform key-pressing and key-releasing movements with their left and right index fingers based on signals (LI and RI). The purpose of using the index fingers of both hands was to manipulate the movement difficulty based on handedness. A complete action consisted of one key-pressing and one key-releasing movement. The results indicated that mind wandering led to slower reaction times and increased reaction variability. There was no difference in reaction times between key-pressing with RI and LI, but key-releasing with RI was significantly faster than with LI. Regarding motor intention, mind wandering attenuated the NS’ EEG component within the 200-millisecond range before the key-pressing. In terms of motor preparation, mind wandering reduced the LRP component within the range of -800 to -200 milliseconds for left-hand actions, indicating that the influence of mind wandering on motor preparation is modulated by handedness. During key-pressing execution, mind wandering reduced midfrontal delta-theta (1-7 Hz) neural oscillatory activity (which is related to motor control) and the contralateral functional connectivity of delta-theta (1-7 Hz). For key-releasing actions, key-releasing with RI induced stronger contralateral delta-theta functional connectivity compared to key-releasing with LI, and mind wandering only attenuated the contralateral delta-theta functional connectivity and midfrontal delta-theta activity of key-releasing with RI, without affecting key-releasing with LI, reflecting the modulation of movement difficulty on the impact of mind wandering on motor control. In Experiment 1, we investigated the effect of mind wandering on EEG aperiodic signal components and found that mind wandering led to an increase in the slope and intercept of aperiodic signal components.

Study 2 examined the modulating role of movement difficulty on the influence of mind wandering on motor control, and contrasted the similarities and differences between the “endogenous interference” of mind wandering on motor control and the “exogenous interference” of working memory task. Experiment 2 manipulated the movement difficulty of response modes in a signal-response task. Before the formal experiment, the reaction times of right-hand single-finger key-pressing and key-releasing were measured, and a two-finger action was further designed, with the right index finger plus middle finger (RIM) as a relatively simple type and the right index finger plus ring finger (RIR) as a relatively difficult type of two-finger action. Similarly, the reaction time results of the formal experiment showed that the RIM key-pressing was faster than RIR key-pressing, but there was no difference in key-releasing. The main finding was that during motor execution, the midfrontal delta-theta activity induced by RIM key-pressing was significantly larger than that induced by RIR key-pressing, and mind wandering only attenuated the midfrontal delta-theta activity of RIM key-pressing, not affecting RIR key-pressing, indicating that movement difficulty modulates the influence of mind wandering on motor control. In Experiment 2, we replicated the finding of mind wandering leading to an increase in the slope and intercept of aperiodic signal components found in Experiment 1, suggesting that aperiodic signal components may serve as more stable biomarkers of mind wandering. To contrast with Experiment 2, Experiment 3 employed a dual-task paradigm, with the primary task being action response and the secondary task being working memory maintenance. The results showed that, unlike mind wandering, maintaining working memory information enhanced motor intention. Similar to mind wandering, during the motor execution, working memory maintenance only reduced midfrontal delta-theta activity of simple movements.

Study 3 investigated the modulating role of background task difficulty on the influence of mind wandering on motor control. While Experiment 2 manipulated the difficulty of the motor response stage, Experiment 4 manipulated the difficulty of sensory and cognitive processing stages by manipulating word frequency to manipulate semantic processing difficulty, requiring participants to perform semantic judgment tasks during the SART task. Low-frequency words corresponded to difficult task condition, and high-frequency words corresponded to simple task condition, with the reaction time results showing significantly faster responses to high-frequency words than to low-frequency words. Experiment 4 mainly found that mind wandering only attenuated the midfrontal delta-theta activity and contralateral delta-theta function connectivity in the high-frequency word condition but not in the low-frequency word condition. Experiment 4 demonstrated that background task difficulty also modulated the influence of mind wandering on motor control. This study employed EEG technology to detail the neural mechanisms underlying the influence of mind wandering on motor control from a temporal dynamic perspective, promoting understanding of this complex phenomenon.

This study also reveals that task difficulty modulates the influence of mind wandering on motor control. A key point of the decoupling hypothesis is that the total amount of executive resources is limited, so the influence of mind wandering should be greater in more difficult tasks. However, if the variable number of executive resources recruited for tasks is considered, according to the executive control failure hypothesis, simple tasks require lower control levels, thus may recruit fewer total executive resources; and according to the resource control account of sustained attention, simple tasks requiring less effort tend to lead to a decrease in motivation to maintain attention on the task, resulting in the allocation of executive resources being more inclined towards mind wandering, whereas the opposite is true for difficult tasks. Therefore, it may be that simple tasks are more susceptible to the influence of mind wandering. The findings of this paper illustrate that the competition and allocation of executive resources between mind wandering and motor control depend on task environments, further integrating and refining relevant theoretical hypotheses of mind wandering.