Biopsychology, Institute of Cognitive Neuroscience, Department of Psychology, Ruhr University, Bochum, Germany.
Biopsychology, Institute of Cognitive Neuroscience, Department of Psychology, Ruhr University, Bochum, Germany.
Behav Brain Res. 2019 May 17;364:114-122. doi: 10.1016/j.bbr.2019.02.021. Epub 2019 Feb 12.
Handedness is the most investigated form of functional hemispheric asymmetries, but its neural correlates remain unclear. Functional imaging studies suggest differences between left- and right-handers in ipsilateral activation during unilateral hand movements, but do not allow for conclusions on the temporal dimension. In the Tapley and Bryden task, subjects have to draw as many dots as possible on a paper within 20 s using either the left or the right hand. We adapted the task for use during EEG in 36 left- and 36 right-handers. Subjects performed a visually guided response task with each trial consisting of eight motor responses. We investigated the lateralized readiness potential (LRP) at the first and last response of the sequence. Overall, increasing complexity of sequences was associated with earlier and less negative LRP peaks. For the last response, right-handers showed more negative LRP peak amplitudes than left-handers. The effect of handedness on LRP peak amplitude in the first response was modulated by task complexity with a more negative LRP peak amplitude in right-handers than left-handers in simple, but not in medium or complex trials. This effect might be due to more symmetrical processing in right-handers with increasing task complexity. These findings complement previous imaging studies and add a new perspective on the relationship between laterality and schizophrenia, associated with less pronounced LRPs and a higher prevalence of left-handedness.
利手性是研究最多的功能偏侧性形式，但它的神经相关性仍不清楚。功能成像研究表明，在单侧手部运动中，左利手和右利手之间存在同侧激活的差异，但不能得出关于时间维度的结论。在 Tapley 和 Bryden 任务中，受试者必须在 20 秒内使用左手或右手尽可能多地在纸上画点。我们将该任务改编为 36 名左利手和 36 名右利手在 EEG 期间使用。受试者用每一次试验中的 8 次运动反应进行视觉引导反应任务。我们研究了序列中第一个和最后一个反应的侧化准备电位（LRP）。总的来说，序列的复杂性增加与 LRP 峰的出现更早且更不消极有关。对于最后一个反应，右利手的 LRP 峰振幅比左利手更负。在第一个反应中，LRP 峰振幅的利手效应受到任务复杂性的调节，即简单任务中右利手的 LRP 峰振幅比左利手更负，而在中等或复杂任务中则不然。这种效应可能是由于右利手在任务复杂性增加时处理更对称。这些发现补充了以前的成像研究，并为偏侧性与精神分裂症之间的关系提供了一个新的视角，与不那么明显的 LRP 和更高的左利手发生率有关。
