Neural signatures of intersensensory attention: investigating the role of neural synchrony and functional network properties

想象一下，你试图在马拉松比赛的人群中认出一个朋友。你可以忽略观众的欢呼，同时专注于运动员的视觉印象。感觉间注意描述的是我们以一种选择的模态关注刺激，而忽略其他模态输入的能力。迄今为止，对感觉间注意的研究主要集中在对实际呈现刺激的加工上。然而，自上而下的感觉间注意定向也会使刺激呈现前的大脑状态产生偏差。功能神经影像学研究表明，感觉间注意可以引起不同皮质区域神经活动的平行和选择性增强和抑制。此外，电生理研究表明，振荡活动所反映的神经同步性可能是其中的重要机制。然而，迄今为止，只有少数研究考察了神经振荡在感觉间注意中的作用。此外，还没有研究调查选定的大脑区域，如初级感觉皮质，对感觉间注意的功能意义。我们将用脑电图（EEG）和经颅磁刺激（TMS）的三个实验来解决这些问题。这三个实验都由一个线索-目标范式组成，在这个范式中，听觉线索指示参与者在视觉-触觉目标刺激出现之前应该将注意力引导到哪种感觉模式（视觉或触觉）。我们将使用最先进的源分析方法来研究当刺激以可变（实验1）或固定（实验2）的刺激间隔（ISI）呈现时，对脑电图记录的神经振荡的影响。值得注意的是，时间注意力定向只在实验2中有用。实验1和2将揭示有注意模态加工的增强和无注意模态加工的抑制在多大程度上与感觉间注意和时间定向有关。在实验3中，我们将单脉冲TMS应用于选定的皮层区域，如初级感觉皮层，在提示-目标间隔期间中断局部皮层加工。我们将使用实验1和2的范例，这将使我们能够得出关于这些区域对感觉间注意的功能意义的结论。综上所述，该项目将进一步加深我们对感觉间注意的神经生理机制及其与时间定向的关系的理解。

Picture yourself trying to spot a friend in the crowd of runners at a marathon. You are able to ignore the cheering of the spectators while simultaneously focusing on the visual impressions of the runners. Intersensory attention describes our ability to attend to stimuli in a selected modality while ignoring input from other modalities. Thus far, studies on intersensory attention have mainly focused on the processing of actually presented stimuli. However, top-down orienting of intersensory attention can also bias the brain states prior to stimulus presentation. Functional neuroimaging studies suggested that intersensory attention can cause parallel and selective enhancements and suppressions of neural activity in different cortical areas. In addition, electrophysiological studies indicated that neural synchrony, as reflected in oscillatory activity, could be an important mechanism therein. To date, however, only a few studies have examined the role of neural oscillations for intersensory attention. Moreover, no study has investigated the functional significance of selected brain areas, such as primary sensory cortices, for intersensory attention. We will address these issues in three experiments using electroencephalography (EEG) and transcranial magnetic stimulation (TMS). All three experiments are comprised of a cue-target paradigm, in which an auditory cue indicates to which sensory modality (visual or tactile) participants should direct their attention prior to the appearance of a visual-tactile target stimulus. We will use state-of-the-art source analysis methods to investigate effects on neural oscillations recorded via EEG when stimuli are presented with variable (Experiment 1) or fixed (Experiment 2) inter-stimulus intervals (ISI). Notably, an orienting of temporal attention is only useful in Experiment 2. Experiments 1 and 2 will reveal novel information about to which degree enhanced processing in the attended modality, and suppression of processing in the unattended modality, relate to intersensory attention and temporal orienting. In Experiment 3, we will apply single-pulse TMS to selected cortical areas, such as primary sensory cortices, to interrupt local cortical processing during the cue-target interval. We will use the paradigms of Experiments 1 and 2, which will allow us to draw conclusions about the functional significance of these regions for intersensory attention. Taken together, the proposed project will further our understanding of the neurophysiological mechanisms underlying intersensory attention and their relationships to temporal orienting.