Visual selective attention studies generally tend to apply cuing paradigms to instructively direct observers’ attention to certain locations, features or objects. However, in real situations, attention in humans often flows spontaneously without any specific instructions. Recently, a concept named “willed attention” was raised in visuospatial attention, in which participants are free to make volitional attention decisions. Several ERP components during willed attention were found, along with a perspective that ongoing alpha activity may bias the subsequent attentional choice. However, it remains unclear whether similar neural mechanisms exist in feature- or object-based willed attention. Here, we included choice cues and instruct cues in a feature-based selective attention paradigm, allowing participants to freely choose or to be instructed to attend a color for the subsequent target detection task. Pre-cue ongoing alpha oscillations, cue-evoked potentials and target-related steady-state visual evoked potentials (SSVEPs) were simultaneously measured as markers of attentional processing. As expected, SSVEP responses were similarly modulated by attention between choice and instruct cue trials. Similar to the case of spatial attention, a willed-attention component (Willed Attention Component, WAC) was isolated during the cue-related choice period by comparing choice and instruct cues. However, pre-cue ongoing alpha oscillations did not predict the color choice (yellow vs blue), as indicated by the chance level decoding accuracy (50%). Overall, our results revealed both similarities and differences between spatial and feature-based willed attention, and thus extended the understanding toward the neural mechanisms of volitional attention.

中文翻译：

---

视觉特征的意志注意选择：脑电图研究

视觉选择性注意研究通常倾向于应用提示范式来指导观察者对某些位置、特征或物体的注意。然而，在现实情况下，人类的注意力往往会在没有任何具体指示的情况下自发流动。最近，视觉空间注意力中提出了一个名为“意志注意”的概念，即参与者可以自由地做出意志性注意决定。我们发现了意愿注意力期间的几个 ERP 成分，以及持续的 alpha 活动可能会偏向随后的注意力选择的观点。然而，目前尚不清楚基于特征或基于对象的意志注意是否存在类似的神经机制。在这里，我们在基于特征的选择性注意范例中包含了选择线索和指示线索，允许参与者自由选择或被指示注意后续目标检测任务的颜色。同时测量提示前持续的 α 振荡、提示诱发电位和目标相关稳态视觉诱发电位 (SSVEP)，作为注意力处理的标记。正如预期的那样，SSVEP 反应同样受到选择和指导线索试验之间注意力的调节。与空间注意的情况类似，通过比较选择和指示线索，在与线索相关的选择期间分离出意志注意成分（Willed Attention Component，WAC）。然而，预提示持续的 alpha 振荡并不能预测颜色选择（黄色与蓝色），如机会级别解码精度 (50%) 所示。总的来说，我们的结果揭示了空间和基于特征的意志注意之间的相似性和差异，从而扩展了对意志注意神经机制的理解。