Smith Marie L, Gosselin Frédéric, Schyns Philippe G
Department of Psychology and Centre for Cognitive Neuroimaging, University of Glasgow, 58 Hillhead Street, Glasgow G12 8QB, United Kingdom.
Proc Natl Acad Sci U S A. 2006 Apr 4;103(14):5626-31. doi: 10.1073/pnas.0508972103. Epub 2006 Mar 27.
Transient periods of synchronized oscillating neuronal discharges in the brain have been proposed to support the discrete perceptual moments underlying conscious visual experience. However, the information content of these perceptual moments remains a critical challenge to the understanding of consciousness. We uncovered this information content in four observers who consciously perceived each interpretation of the ambiguous Dali painting Slave Market with the Disappearing Bust of Voltaire. For each individual observer, we isolated the stimulus spatial frequency (SF) features underlying their overt judgments of the input as "the nuns" and "Voltaire". Every 2 ms between stimulus onset and overt response, we derived the sensitivity of the observer's oscillatory brain activity (in the theta, alpha, and beta bandwidths) to these SF features. Then, in each bandwidth, we estimated the moments (between stimulus onset and perceptual judgment) when perception-specific SF features were maximally integrated, corresponding to perceptual moments. We show that the centroparietal beta oscillations support perceptual moments underlying the conscious perception of the nuns, whereas theta oscillations support the perception of Voltaire. For both perceptions, we reveal the specific information content of these perceptual moments.
大脑中同步振荡的神经元放电的短暂时期被认为是支持有意识视觉体验背后离散感知时刻的基础。然而，这些感知时刻的信息内容仍然是理解意识的一个关键挑战。我们在四名观察者身上揭示了这些信息内容，他们有意识地感知了达利的 ambiguous 画作《伏尔泰半身像渐隐的奴隶市场》的每一种解读。对于每一位个体观察者，我们分离出了他们将输入明显判断为“修女”和“伏尔泰”背后的刺激空间频率（SF）特征。在刺激开始到明显反应之间的每2毫秒，我们得出观察者的振荡脑活动（在θ、α和β带宽）对这些SF特征的敏感性。然后，在每个带宽中，我们估计了（在刺激开始到感知判断之间）感知特定的SF特征最大程度整合的时刻，即对应于感知时刻。我们表明，中央顶叶β振荡支持对修女的有意识感知背后的感知时刻，而θ振荡支持对伏尔泰的感知。对于这两种感知，我们揭示了这些感知时刻的具体信息内容。
