Movement preparation and initiation have been shown to involve large scale brain networks. Recent findings suggest that movement preparation and initiation are represented in functionally distinct cortical networks. In electroencephalographic (EEG) recordings, movement initiation is reflected as a strong negative potential at medial central channels that is phase-locked to the movement onset - the movement-related cortical potential (MRCP). Movement preparation describes the process of transforming high level movement goals to low level commands. An integral part of this transformation process is directional processing (i.e., where to move). The processing of movement direction during visuomotor and oculomotor tasks is associated with medial parieto-occipital cortex (PO) activity, phase-locked to the presentation of potential movement goals. We surmised that the network generating the MRCP (movement initiation) would encode less information about movement direction than the parieto-occipital network processing movement direction. Here, we studied delta band EEG activity during center-out reaching movements (2D; 4 directions) in visuomotor and oculomotor tasks. In 15 healthy participants, we found a consistent representation of movement direction in PO 300–400 ms after the direction cue irrespective of the task. Despite generating the MRCP, sensorimotor areas (SM) encoded less information about the movement direction than PO. Moreover, the encoded directional information in SM was less consistent across participants and specific to the visuomotor task. In a classification approach, we could infer the four movement directions from the delta band EEG activity with moderate accuracies up to 55.9%. The accuracies for cue-aligned data were significantly higher than for movement onset-aligned data in either task, which also suggests a stronger representation of movement direction during movement preparation. Therefore, we present direct evidence that EEG delta band amplitude modulations carry information about both arm movement initiation and movement direction, and that they are represented in two distinct cortical networks.

中文翻译：

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手部运动启动和定向处理的不同皮质网络：脑电图研究

运动准备和启动已被证明涉及大规模的大脑网络。最近的研究结果表明，运动准备和启动体现在功能不同的皮质网络中。在脑电图 (EEG) 记录中，运动开始被反映为内侧中央通道的强负电位，该电位与运动开始 - 运动相关皮层电位 (MRCP) 相锁定。运动准备描述了将高级别运动目标转换为低级别命令的过程。这个转换过程的一个组成部分是定向处理（即移动到哪里）。视觉运动和眼球运动任务期间运动方向的处理与内侧顶枕叶皮层 (PO) 活动相关，与潜在运动目标的呈现锁相。我们推测，与顶枕叶网络处理运动方向相比，生成 MRCP（运动启动）的网络编码的运动方向信息更少。在这里，我们研究了视觉运动和眼球运动任务中外伸运动（2D；4 个方向）期间的 delta 波段 EEG 活动。在 15 名健康参与者中，我们在方向提示后 300-400 毫秒内发现了一致的运动方向表示，而与任务无关。尽管生成了 MRCP，但感觉运动区 (SM) 编码的关于运动方向的信息比 PO 少。此外，SM 中编码的方向信息在参与者之间不太一致，并且特定于视觉运动任务。在分类方法中，我们可以从 delta 波段 EEG 活动中推断出四个运动方向，准确度高达 55.9%。在任何一项任务中，线索对齐数据的准确度都显着高于运动开始对齐数据，这也表明在运动准备过程中运动方向的表现更强。因此，我们提出直接证据表明 EEG delta 波段幅度调制携带有关手臂运动起始和运动方向的信息，并且它们在两个不同的皮质网络中表示。