Centre for Brain Science, Department of Psychology, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom,
Facultad de Lenguas y Educación, Universidad Nebrija, 28015 Madrid, Spain.
J Neurosci. 2019 Jul 17;39(29):5711-5718. doi: 10.1523/JNEUROSCI.3184-18.2019. Epub 2019 May 20.
The presentation of simple auditory stimuli can significantly impact visual processing and even induce visual illusions, such as the auditory-induced double flash illusion (DFI). These cross-modal processes have been shown to be driven by occipital oscillatory activity within the alpha band. Whether this phenomenon is network specific or can be generalized to other sensory interactions remains unknown. The aim of the current study was to test whether cross-modal interactions between somatosensory-to-visual areas leading to the same (but tactile-induced) DFI share similar properties with the auditory DFI. We hypothesized that if the effects are mediated by the oscillatory properties of early visual areas per se, then the two versions of the illusion should be subtended by the same neurophysiological mechanism (i.e., the speed of the alpha frequency). Alternatively, if the oscillatory activity in visual areas predicting this phenomenon is dependent on the specific neural network involved, then it should reflect network-specific oscillatory properties. In line with the latter, results recorded in humans (both sexes) show a network-specific oscillatory profile linking the auditory DFI to occipital alpha oscillations, replicating previous findings, and tactile DFI to occipital beta oscillations, a rhythm typical of somatosensory processes. These frequency-specific effects are observed for visual (but not auditory or somatosensory) areas and account for auditory-visual connectivity in the alpha band and somatosensory-visual connectivity in the beta band. We conclude that task-dependent visual oscillations reflect network-specific oscillatory properties favoring optimal directional neural communication timing for sensory binding. We investigated the oscillatory correlates of the auditory- and tactile-induced double flash illusion (DFI), a phenomenon where two interleaved beeps (taps) set within 100 ms apart and paired with one visual flash induce the sensation of a second illusory flash. Results confirm previous evidence that the speed of individual occipital alpha oscillations predict the temporal window of the auditory-induced illusion. Importantly, they provide novel evidence that the tactile-induced DFI is instead mediated by the speed of individual occipital beta oscillations. These task-dependent occipital oscillations are shown to be mediated by the oscillatory properties of the neural network engaged in the task to favor optimal temporal integration between the senses.
简单听觉刺激的呈现会显著影响视觉处理,甚至会引起视觉错觉,如听觉诱导的双闪光错觉(DFI)。这些跨模态过程被证明是由 alpha 波段中的枕部振荡活动驱动的。这种现象是否是特定于网络的,或者是否可以推广到其他感觉相互作用,目前还不得而知。本研究的目的是测试感觉到视觉区域之间的跨模态相互作用是否导致相同的(但触觉诱导的)DFI 具有相似的特性与听觉 DFI。我们假设,如果这些影响是由早期视觉区域的振荡特性本身介导的,那么两种错觉版本都应该由相同的神经生理机制(即 alpha 频率的速度)来暗示。或者,如果预测这种现象的视觉区域中的振荡活动依赖于所涉及的特定神经网络,则它应该反映网络特有的振荡特性。与后者一致,在人类(男女)中记录的结果显示,与听觉 DFI 相关的特定网络的振荡特征与枕部 alpha 振荡相关联,复制了先前的发现,以及与触觉 DFI 相关联的枕部 beta 振荡,这是一种典型的体感过程节律。这些频率特异性效应在视觉区域中观察到(而不是听觉或体感),并解释了 alpha 波段中的听觉-视觉连接和 beta 波段中的体感-视觉连接。我们得出结论,任务相关的视觉振荡反映了网络特有的振荡特性,有利于感官绑定的最佳定向神经通信时间。我们研究了听觉和触觉诱导的双闪光错觉(DFI)的振荡相关性,这种现象是指两个交错的哔哔声(轻敲)在 100 毫秒内设置并与一个视觉闪光配对,会引起第二个幻觉闪光的感觉。结果证实了先前的证据,即个体枕部 alpha 振荡的速度预测了听觉诱导错觉的时间窗口。重要的是,它们提供了新的证据,表明触觉诱导的 DFI 是由个体枕部 beta 振荡的速度介导的。这些任务相关的枕部振荡被证明是由参与任务的神经网络的振荡特性介导的,以有利于感官之间的最佳时间整合。