Eye-Tracking Laboratory, Brain and Consciousness Research Center, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; Institute of Cognitive Neuroscience, College of Health Science and Technology, National Central University, Taoyuan City, Taiwan; Department of Physical Activity and Sport Science, Universidad Peruana de Ciencias Aplicadas, Lima, Peru.
Department of Anesthesiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei City, Taiwan; Department of Anesthesiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
Neuropsychologia. 2023 Aug 13;187:108626. doi: 10.1016/j.neuropsychologia.2023.108626. Epub 2023 Jun 17.
Microsaccades that occur during periods of fixation are modulated by various cognitive processes and have an impact on visual processing. A network of brain areas is involved in microsaccade generation, including the superior colliculus and frontal eye field (FEF) which are involved in modulating microsaccade rate and direction after the appearance of a visual cue (referred to as microsaccade cueing modulation). Although the neural mechanisms underlying microsaccade cueing modulations have been demonstrated in monkeys, limited research has investigated a causal role of these areas in humans. By applying continuous theta-burst transcranial magnetic stimulation (cTBS) over the right FEF and vertex, we investigated the role of human FEF in modulating microsaccade responses after the appearance of a visual target in a visual- and memory-delay saccade task. After target appearance, microsaccade rate was initially suppressed but then increased in both cTBS conditions. More importantly, in the visual-delay task, microsaccades after target appearance were directed to the ipsilateral side more often with FEF, compared to vertex stimulation. Moreover, microsaccades were directed towards the target location, then to the opposite location of the target in both tasks, with larger effects in the visual-, compared to, memory-delay task. This microsaccade direction modulation was delayed after FEF stimulation in the memory-delay task. Overall, some microsaccade cueing modulations were moderately disrupted after FEF cTBS, suggesting a causal role for involvement of the human FEF in microsaccade generation after presentation of salient stimuli.
微扫视是在注视期间发生的，受各种认知过程的调节，对视觉处理有影响。生成微扫视的大脑区域网络包括上丘和额眼区（FEF），它们在视觉线索出现后（称为微扫视线索调制）调节微扫视的速度和方向。虽然在猴子中已经证明了微扫视线索调制的神经机制，但在人类中，对这些区域的因果作用的研究有限。通过在右侧 FEF 和顶点施加连续 theta 爆发经颅磁刺激（cTBS），我们研究了人类 FEF 在视觉和记忆延迟扫视任务中在视觉目标出现后调节微扫视反应的作用。目标出现后，在两种 cTBS 条件下，微扫视率最初受到抑制，但随后增加。更重要的是，在视觉延迟任务中，与顶点刺激相比，FEF 刺激后微扫视更倾向于向同侧。此外，在两种任务中，微扫视都先指向目标位置，然后指向目标的相反位置，在视觉延迟任务中，效果比记忆延迟任务更大。在记忆延迟任务中，FEF 刺激后微扫视方向的这种调制被延迟。总体而言，FEF cTBS 后微扫视线索调制受到中度破坏，这表明人类 FEF 在呈现显著刺激后生成微扫视中存在因果作用。
