Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Laboratory for Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Schizophr Bull. 2023 Feb 24;49(12 Suppl 2):S68-S81. doi: 10.1093/schbul/sbac140.
Approximately one-third of patients with a psychotic disorder experience visual hallucinations (VH). While new, more targeted treatment options are warranted, the pathophysiology of VH remains largely unknown. Previous studies hypothesized that VH result from impaired functioning of the vision-related networks and impaired interaction between those networks, including a possible functional disconnection between the primary visual cortex (V1) and higher-order visual processing regions. Testing these hypotheses requires sufficient data on brain activation during actual VH, but such data are extremely scarce.
We therefore recruited seven participants with a psychotic disorder who were scanned in a 3 T fMRI scanner while indicating the occurrence of VH by pressing a button. Following the scan session, we interviewed participants about the VH experienced during scanning. We then used the fMRI scans to identify regions with increased or decreased activity during VH periods versus baseline (no VH).
In six participants, V1 was not activated during VH, and in one participant V1 showed decreased activation. All participants reported complex VH such as human-like beings, objects and/or animals, during which higher-order visual areas and regions belonging to the vision-related networks on attention and memory were activated.
These results indicate that VH are associated with diffuse involvement of the vision-related networks, with the exception of V1. We therefore propose a model for the pathophysiology of psychotic VH in which a dissociation of higher-order visual processing areas from V1 biases conscious perception away from reality and towards internally generated percepts.
大约三分之一的精神病患者会出现幻视 (VH)。虽然需要新的、更有针对性的治疗方法，但 VH 的病理生理学仍然很大程度上未知。先前的研究假设 VH 是由于视觉相关网络的功能障碍以及这些网络之间的相互作用受损引起的，包括初级视觉皮层 (V1) 和更高阶视觉处理区域之间可能存在的功能连接中断。要验证这些假设，需要在实际出现 VH 时获得有关大脑激活的足够数据，但这种数据非常稀缺。
因此，我们招募了 7 名患有精神病的参与者，他们在 3T fMRI 扫描仪中进行扫描，同时通过按下按钮来指示 VH 的发生。扫描后，我们对参与者进行了有关扫描过程中经历的 VH 的访谈。然后，我们使用 fMRI 扫描来识别 VH 期间与基线（无 VH）相比活性增加或减少的区域。
在 6 名参与者中，V1 在 VH 期间未被激活，而在 1 名参与者中 V1 的活性降低。所有参与者报告了复杂的 VH，例如人形生物、物体和/或动物，在此期间，高阶视觉区域和注意力与记忆相关的视觉网络区域被激活。
这些结果表明，VH 与视觉相关网络的广泛参与有关，除了 V1。因此，我们提出了一种精神病 VH 的病理生理学模型，其中高阶视觉处理区域与 V1 的分离会使意识感知偏离现实，偏向于内部产生的感知。
