Cognitive and Motor Rehabilitation and Neuroimaging Unit, IRCCS Fondazione Santa Lucia, Rome, Italy.
Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
Hum Brain Mapp. 2019 Jun 1;40(8):2449-2463. doi: 10.1002/hbm.24535. Epub 2019 Jan 31.
Mental imagery and visual perception rely on the same content-dependent brain areas in the high-level visual cortex (HVC). However, little is known about dynamic mechanisms in these areas during imagery and perception. Here we disentangled local and inter-regional dynamic mechanisms underlying imagery and perception in the HVC and the hippocampus (HC), a key region for memory retrieval during imagery. Nineteen healthy participants watched or imagined a familiar scene or face during fMRI acquisition. The neural code for familiar landmarks and faces was distributed across the HVC and the HC, although with a different representational structure, and generalized across imagery and perception. However, different regional adaptation effects and inter-regional functional couplings were detected for faces and landmarks during imagery and perception. The left PPA showed opposite adaptation effects, with activity suppression following repeated observation of landmarks, but enhancement following repeated imagery of landmarks. Also, functional coupling between content-dependent brain areas of the HVC and HC changed as a function of task and content. These findings provide important information about the dynamic networks underlying imagery and perception in the HVC and shed some light upon the thin line between imagery and perception which has characterized the neuropsychological debates on mental imagery.
表象和视觉感知依赖于高级视觉皮层(HVC)中相同的内容相关脑区。然而,对于表象和感知过程中这些区域的动态机制知之甚少。在这里,我们分离了表象和感知过程中 HVC 和海马体(HC)的局部和区域间动态机制,海马体是表象过程中记忆检索的关键区域。19 名健康参与者在 fMRI 采集期间观看或想象一个熟悉的场景或面孔。尽管代表结构不同,但熟悉地标和面孔的神经编码分布在 HVC 和 HC 中,并在表象和感知中具有通用性。然而,在表象和感知过程中,面孔和地标会检测到不同的区域适应效应和区域间功能耦合。左侧 PPA 表现出相反的适应效应,地标重复观察后活动抑制,但地标重复表象后活动增强。此外,HVC 和 HC 的内容相关脑区之间的功能耦合随任务和内容而变化。这些发现为 HVC 中表象和感知的动态网络提供了重要信息,并为神经心理学关于表象的争论中表象和感知之间的细微界限提供了一些启示。