Visser Yvonne F, Medendorp W Pieter, Selen Luc P J
Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.
Physiol Rep. 2025 Mar;13(6):e70237. doi: 10.14814/phy2.70237.
Evidence accumulation processes during decision-making are thought to continuously feed into the motor system, preparing multiple competing motor plans, of which one is executed when the evidence is complete. Previously, the state of this accumulation process has been studied by reading out the preparatory state of the motor system with evoked responses, once per trial. In this study, we aim to continuously track the sensorimotor decision during the trial using corticomuscular (CMC) and intermuscular coherence (IMC). We recorded EEG and EMG of healthy young adults (n = 34) who viewed random dot motion stimuli, with varying strengths across trials, and indicated their perceived motion direction by reaching towards one of two targets, requiring either flexion or extension of the elbow. Coherence was computed in the beta band. After stimulus presentation, both CMC and IMC show an initial phasic pattern, which is followed by sustained coherence patterns at a level that depends on stimulus strength for CMC. Prior to reach onset, the CMC for different stimulus strengths had a tendency to settle at similar levels. This tendency tentatively marks a stimulus-independent decision bound. We conclude that CMC, and to a lesser extent IMC, track the evidence accumulation process on a single trial.
决策过程中的证据积累过程被认为会持续输入到运动系统中，准备多个相互竞争的运动计划，当证据完备时执行其中一个计划。此前，这一积累过程的状态是通过在每次试验中读取运动系统的准备状态并利用诱发反应来进行研究的。在本研究中，我们旨在使用皮质肌肉（CMC）和肌间相干性（IMC）在试验过程中持续追踪感觉运动决策。我们记录了健康年轻成年人（n = 34）的脑电图（EEG）和肌电图（EMG），这些受试者观看随机点运动刺激，每次试验刺激强度不同，并通过向两个目标之一伸手来指示他们感知到的运动方向，这需要肘部进行屈曲或伸展。相干性是在β波段计算的。刺激呈现后，CMC和IMC均显示出初始的相位模式，随后是持续的相干模式，其水平取决于CMC的刺激强度。在伸手开始之前，不同刺激强度的CMC倾向于稳定在相似水平。这种倾向初步标志着一个与刺激无关的决策界限。我们得出结论，CMC以及在较小程度上的IMC能够在单次试验中追踪证据积累过程。
