The hippocampus and ventromedial prefrontal cortex (vmPFC) play key roles in numerous cognitive domains including mind-wandering, episodic memory, and imagining the future. Perspectives differ on precisely how they support these diverse functions, but there is general agreement that it involves constructing representations composed of numerous elements. Visual scenes have been deployed extensively in cognitive neuroscience because they are paradigmatic multielement stimuli. However, it remains unclear whether scenes, rather than other types of multifeature stimuli, preferentially engage hippocampus and vmPFC. Here, we leveraged the high temporal resolution of magnetoencephalography to test participants as they gradually built scene imagery from three successive auditorily presented object descriptions and an imagined 3-D space. This was contrasted with constructing mental images of nonscene arrays that were composed of three objects and an imagined 2-D space. The scene and array stimuli were, therefore, highly matched, and this paradigm permitted a closer examination of step-by-step mental construction than has been undertaken previously. We observed modulation of theta power in our two regions of interest—anterior hippocampus during the initial stage and vmPFC during the first two stages, of scene relative to array construction. Moreover, the scene-specific anterior hippocampal activity during the first construction stage was driven by the vmPFC, with mutual entrainment between the two brain regions thereafter. These findings suggest that hippocampal and vmPFC neural activity is especially tuned to scene representations during the earliest stage of their formation, with implications for theories of how these brain areas enable cognitive functions such as episodic memory.

海马体和腹内侧前额叶皮层 (vmPFC) 在许多认知领域中发挥着关键作用，包括走神、情景记忆和想象未来。关于它们如何支持这些不同功能的观点不同，但普遍同意它涉及构建由众多元素组成的表示。视觉场景已广泛应用于认知神经科学，因为它们是典型的多元素刺激。然而，尚不清楚场景，而不是其他类型的多特征刺激，是否优先参与海马和 vmPFC。在这里，我们利用脑磁图的高时间分辨率来测试参与者，因为他们逐渐从三个连续的听觉呈现的对象描述和想象的 3-D 空间构建场景图像。这与构建由三个对象和一个想象的二维空间组成的非场景阵列的心理图像形成对比。因此，场景和阵列刺激高度匹配，这种范式允许比以前更仔细地检查逐步的心理建设。我们观察到两个感兴趣区域的 theta 功率调制 - 初始阶段的前海马体和前两个阶段的 vmPFC，与阵列构建相关的场景。此外，在第一个构建阶段，特定场景的前海马活动由 vmPFC 驱动，此后两个大脑区域之间相互夹带。这些发现表明，海马和 vmPFC 神经活动在其形成的最早阶段特别适合场景表征，