University Medical Center Hamburg-Eppendorf, Department of Neurophysiology and Pathophysiology, Hamburg, Germany.
University of Osnabrück, Institute of Cognitive Science, Osnabrück, Germany.
Sci Rep. 2019 Mar 22;9(1):5030. doi: 10.1038/s41598-019-41636-w.
Multisensory perception is shaped by both attentional selection of relevant sensory inputs and exploitation of stimulus-driven factors that promote cross-modal binding. Underlying mechanisms of both top-down and bottom-up modulations have been linked to changes in alpha/gamma dynamics in primary sensory cortices and temporoparietal cortex. Accordingly, it has been proposed that alpha oscillations provide pulsed inhibition for gamma activity and thereby dynamically route cortical information flow. In this study, we employed a recently introduced multisensory paradigm incorporating both bottom-up and top-down aspects of cross-modal attention in an EEG study. The same trimodal stimuli were presented in two distinct attentional conditions, focused on visual-tactile or audio-visual components, for which cross-modal congruence of amplitude changes had to be evaluated. Neither top-down nor bottom-up cross-modal attention modulated alpha or gamma power in primary sensory cortices. Instead, we found alpha band effects in bilateral frontal and right parietal cortex. We propose that frontal alpha oscillations reflect the origin of top-down control regulating perceptual gains and that modulations of parietal alpha oscillations relates to intersensory re-orienting. Taken together, we suggest that the idea of selective cortical routing via alpha oscillations can be extended from sensory cortices to the frontoparietal attention network.
多感觉感知受到注意力对相关感觉输入的选择以及利用促进跨模态绑定的刺激驱动因素的影响。自上而下和自下而上调节的潜在机制都与初级感觉皮层和颞顶叶皮层中 alpha/gamma 动力学的变化有关。因此，有人提出 alpha 振荡为 gamma 活动提供脉冲抑制，从而动态地引导皮质信息流。在这项研究中，我们在 EEG 研究中采用了一种新引入的多感觉范式，该范式结合了跨模态注意的自上而下和自下而上的方面。相同的三模态刺激在两种不同的注意条件下呈现，分别集中在视觉触觉或视听成分上，必须评估这些成分的幅度变化的跨模态一致性。自上而下和自下而上的跨模态注意都没有调节初级感觉皮层中的 alpha 或 gamma 功率。相反，我们在双侧额和右顶叶皮层中发现了 alpha 频段的效应。我们提出，额叶 alpha 振荡反映了自上而下控制调节感知增益的起源，而顶叶 alpha 振荡的调制与感觉间重新定向有关。总之，我们认为，通过 alpha 振荡进行选择性皮质路由的想法可以从感觉皮层扩展到额顶叶注意网络。
