Brancucci Alfredo, Lugli Victor, Perrucci Mauro Gianni, Del Gratta Cosimo, Tommasi Luca
Section of Experimental Psychology, Department of Psychological Sciences, Humanities and the Territory, "G. d'Annunzio" University of Chieti and Pescara, Via dei Vestini 31, 66100, Chieti Scalo, Italy.
Department of Neuroscience and Imaging, "G. d'Annunzio" University of Chieti and Pescara, Via dei Vestini 31, 66100, Chieti Scalo, Italy.
Brain Struct Funct. 2016 Jan;221(1):463-72. doi: 10.1007/s00429-014-0918-2. Epub 2014 Oct 25.
Hemodynamic correlates of consciousness were investigated in humans during the presentation of a dichotic sequence inducing illusory auditory percepts with features analogous to visual multistability. The sequence consisted of a variation of the original stimulation eliciting the Deutsch's octave illusion, created to maintain a stable illusory percept long enough to allow the detection of the underlying hemodynamic activity using functional magnetic resonance imaging (fMRI). Two specular 500 ms dichotic stimuli (400 and 800 Hz) presented in alternation by means of earphones cause an illusory segregation of pitch and ear of origin which can yield up to four different auditory percepts per dichotic stimulus. Such percepts are maintained stable when one of the two dichotic stimuli is presented repeatedly for 6 s, immediately after the alternation. We observed hemodynamic activity specifically accompanying conscious experience of pitch in a bilateral network including the superior frontal gyrus (SFG, BA9 and BA10), medial frontal gyrus (BA6 and BA9), insula (BA13), and posterior lateral nucleus of the thalamus. Conscious experience of side (ear of origin) was instead specifically accompanied by bilateral activity in the MFG (BA6), STG (BA41), parahippocampal gyrus (BA28), and insula (BA13). These results suggest that the neural substrate of auditory consciousness, differently from that of visual consciousness, may rest upon a fronto-temporal rather than upon a fronto-parietal network. Moreover, they indicate that the neural correlates of consciousness depend on the specific features of the stimulus and suggest the SFG-MFG and the insula as important cortical nodes for auditory conscious experience.
在呈现一种双耳序列时，对人类意识的血流动力学相关性进行了研究，该序列会诱发具有类似于视觉多稳态特征的虚幻听觉感知。该序列由引发多伊奇八度错觉的原始刺激的变体组成，其设计目的是保持稳定的虚幻感知足够长的时间，以便使用功能磁共振成像（fMRI）检测潜在的血流动力学活动。通过耳机交替呈现的两个镜面500毫秒双耳刺激（400和800赫兹）会导致音高和声源耳朵的虚幻分离，每个双耳刺激可产生多达四种不同的听觉感知。当两个双耳刺激之一在交替后立即重复呈现6秒时，这种感知会保持稳定。我们观察到在一个双侧网络中，血流动力学活动特别伴随着音高的有意识体验，该网络包括额上回（SFG，BA9和BA10）、额中回（BA6和BA9）、脑岛（BA13）和丘脑后外侧核。相反，关于声源耳朵一侧的有意识体验特别伴随着额中回（BA6）、颞上回（BA41）、海马旁回（BA28）和脑岛（BA13）的双侧活动。这些结果表明，与视觉意识不同，听觉意识的神经基础可能依赖于额颞网络而非额顶网络。此外，它们表明意识的神经相关性取决于刺激的特定特征，并表明额上回 - 额中回和脑岛是听觉有意识体验的重要皮质节点。
