To behave adaptively with sufficient flexibility, biological organisms must cognize beyond immediate reaction to a physically present stimulus. For this, humans use visual mental imagery [1, 2], the ability to conjure up a vivid internal experience from memory that stands in for the percept of the stimulus. Visually imagined contents subjectively mimic perceived contents, suggesting that imagery and perception share common neural mechanisms. Using multivariate pattern analysis on human electroencephalography (EEG) data, we compared the oscillatory time courses of mental imagery and perception of objects. We found that representations shared between imagery and perception emerged specifically in the alpha frequency band. These representations were present in posterior, but not anterior, electrodes, suggesting an origin in parieto-occipital cortex. Comparison of the shared representations to computational models using representational similarity analysis revealed a relationship to later layers of deep neural networks trained on object representations, but not auditory or semantic models, suggesting representations of complex visual features as the basis of commonality. Together, our results identify and characterize alpha oscillations as a cortical signature of representations shared between visual mental imagery and perception.

为了以足够的灵活性进行适应性行为，生物有机体必须在对物理刺激的直接反应之外进行认知。为此，人类使用视觉心理意象 [1, 2]，这种能力可以从代表刺激感知的记忆中唤出生动的内部体验。视觉想象的内容主观地模仿感知的内容，这表明图像和感知具有共同的神经机制。使用对人类脑电图 (EEG) 数据的多元模式分析，我们比较了心理意象和物体感知的振荡时间过程。我们发现图像和感知之间共享的表示特别出现在 alpha 频带中。这些表征存在于后部而非前部电极中，表明起源于顶枕叶皮层。使用表征相似性分析将共享表征与计算模型进行比较，揭示了与在对象表征上训练的深层神经网络的后续层的关系，而不是听觉或语义模型，这表明复杂视觉特征的表征是共性的基础。总之，我们的结果将 alpha 振荡识别和表征为视觉心理意象和感知之间共享的表征的皮层特征。