Neural temporal dynamics of facilitation and suppression in top-down guided feature-based attention

该项目旨在研究基于特征的注意（FBA）中促进和抑制的基本神经动力学。注意领域的一个核心问题是，视觉处理是否是一种严格有限的资源，必须通过选择性注意有选择地和节俭地分配。如果是这样的话，对一个刺激的注意增强必然会导致对未被注意的干扰刺激的抑制。然而，在我们之前对FBA注意转移的时间动态研究中，我们不断发现一个双相过程，即被注意特征（颜色）的快速促进，随后被忽略特征（颜色）的抑制，时间延迟约为120-140 ms。在这里，我们将提出一个新的统一的时间神经动力学框架，该框架整合了FBA中神经增益、竞争和抑制的基本神经原理。虽然我们多次重复了双相过程，但一些审稿人在各自的发表过程中提出了一些关键问题，需要实验关注以排除其他解释。这些问题围绕着频率标记刺激的使用，主要是集中分析稳态视觉诱发电位（ssvep）的限制。在建议的项目中，我们打算进行3项研究，将我们的研究扩展到使用探针设计的行为数据，并同时分析由包含任务和探针刺激的事件引发的erp。我们相信，这种多模式方法将大大加强我们对FBA中注意转移的注意资源分配的替代框架的建议。在进一步的探索性研究中，我们打算测试自上而下选择驱动和硬连线中心环绕抑制驱动两种选择的时间过程和抑制时间点。一项进一步的探索性研究旨在验证我们的观点，即早期增益调制和随后的竞争相互作用不是相互独立的，而是初始放大增益在触发抑制之前需要达到临界水平。如果抑制起作用，我们想测试促进和抑制是否会在竞争互动中产生互惠关系。我们相信，这些发现将丰富现有的注意力模型，因此，计算模型以及在各自算法中实现放大和抑制的方式也应该是最感兴趣的。

The proposed project sets out to investigate basic neural dynamics of facilitation and suppression in feature-based attention (FBA). A central question in the field of attention is whether visual processing is a strictly limited resource, which must be selectively and frugally allocated by selective attention. If this were the case, attentional enhancement of one stimulus should invariably lead to suppression of unattended distracter stimuli. However, in our previous studies in which we investigated the temporal dynamics of attentional shifts in FBA, we constantly found a biphasic process, with fast facilitation of the to-be-attended feature (color) followed by suppression of the to-be-ignored feature (color) with a time delay in the range of about 120-140 ms. Here, we will propose a new unified framework of temporal neuronal dynamics of attentional shifting that integrates the basic neural principles of neural gain, competition and suppression in FBA. While we replicated that biphasic process several times, some reviewers were asking some critical questions during the respective publication process that need experimental attention to exclude alternative explanations. These questions revolved around the usage of frequency-tagged stimuli and mainly the restriction to focus the analysis to steady state visual evoked potentials (SSVEPs). In the suggested project, we intend to run 3 studies extending our research to behavioral data employing a probe design and concurrently analyze ERPs that are elicited by events that comprise the task and probe stimuli. We are convinced that such a multi-modal approach will significantly strengthen our suggestion for an alternative framework for the allocation of attentional resources of attentional shifts in FBA. In further explorative studies, we intend to test the time course and the time point of suppression when selection is driven by top-down selection or driven by hard-wired center surround suppression. A further explorative study intends to test our idea that early gain modulation and the subsequent competitive interactions are not independent of each other, but instead, that initial amplification gain needs to reach a critical level before it triggers suppression. If suppression comes into play, we want to test whether facilitation and suppression result in a reciprocal relationship in that competitive interaction. We are convinced that these findings would enrich existing models of attention, and thus, should also be of highest interest to computational models and the way amplification and suppression are implemented in the respective algorithms.