Visual hallucinations are an underappreciated symptom affecting the majority of patients during the natural history of Parkinson's disease. Little is known about other forms of abstract and internally generated cognition - such as mind-wandering - in this population, but emerging evidence suggests that an interplay between the brain's primary visual and default networks might play a crucial role in both internally generated imagery and hallucinations. Here, we explored the association between mind-wandering and visual hallucinations in Parkinson's disease, and their relationship with brain network coupling. We administered a validated thought-sampling task to 38 Parkinson's disease patients (18 with hallucinations; 20 without) and 40 controls, to test the hypothesis that individuals with hallucinations experience an increased frequency of mind-wandering. Group differences in the association between mind-wandering frequency and brain network coupling were also examined using resting state functional magnetic resonance imaging. Our results showed that patients with hallucinations exhibited significantly higher mind-wandering frequencies compared to non-hallucinators, who in turn had reduced levels of mind-wandering relative to controls. At the level of brain networks, inter-network connectivity and seed-to-voxel analyses identified that increased mind-wandering in the hallucinating versus non-hallucinating group was associated with greater coupling between the primary visual cortex and dorsal default network. Taken together, our results suggest a relative preservation of mind-wandering in Parkinson's disease patients who experience visual hallucinations, which is associated with increased visual cortex-default network coupling. We propose that the preservation of florid abstract and internally generated cognition in the context of the Parkinson's disease can contribute to visual hallucinations, whereas healthy individuals experience only the vivid images of the mind's eye. These findings refine current models of visual hallucinations by identifying a specific cognitive phenomenon and neural substrate consistent with the top-down influences over perception that have been implicated in hallucinations across neuropsychiatric disorders.

中文翻译：

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帕金森病幻觉中的走神反映了初级视觉和默认网络耦合。

在帕金森病的自然病程中，幻视是影响大多数患者的一种未被充分认识的症状。对这一人群中其他形式的抽象和内部生成的认知知之甚少，例如走神. 在这里，我们探讨了帕金森病中走神和幻视之间的关联，以及它们与脑网络耦合的关系。我们对 38 名帕金森病患者（18 名有幻觉；20 名没有幻觉）和 40 名对照者进行了经过验证的思维采样任务，以检验幻觉患者的走神频率增加的假设。还使用静息状态功能磁共振成像检查了走神频率和大脑网络耦合之间关联的组差异。我们的结果表明，与非幻觉者相比，幻觉患者表现出明显更高的走神频率，而相对于对照组，后者的走神水平降低。在大脑网络层面，网络间连接和种子到体素分析表明，幻觉组与非幻觉组的走神增加与初级视觉皮层和背侧默认网络之间更大的耦合有关。综合起来，我们的结果表明，在经历视幻觉的帕金森病患者中，走神的相对保留，这与视觉皮层默认网络耦合增加有关。我们提出，在帕金森病的背景下，保留华丽的抽象和内部生成的认知可能会导致视觉幻觉，而健康的人只会体验到心灵眼睛的生动图像。这些发现通过识别特定的认知现象和神经基质，与自上而下的感知影响一致，这些影响与神经精神疾病的幻觉有关，从而改进了当前的幻觉模型。这与增加的视觉皮层-默认网络耦合有关。我们提出，在帕金森病的背景下，保留华丽的抽象和内部生成的认知可能会导致视觉幻觉，而健康的人只会体验到心灵眼睛的生动图像。这些发现通过识别特定的认知现象和神经基质，与自上而下的感知影响一致，这些影响与神经精神疾病的幻觉有关，从而改进了当前的幻觉模型。这与增加的视觉皮层-默认网络耦合有关。我们提出，在帕金森病的背景下，保留华丽的抽象和内部生成的认知可能会导致视觉幻觉，而健康的人只会体验到心灵眼睛的生动图像。这些发现通过识别特定的认知现象和神经基质，与自上而下的感知影响一致，这些影响与神经精神疾病的幻觉有关，从而改进了当前的幻觉模型。而健康的人只能体验到心灵之眼的生动图像。这些发现通过识别特定的认知现象和神经基质，与自上而下的感知影响一致，这些影响与神经精神疾病的幻觉有关，从而改进了当前的幻觉模型。而健康的人只能体验到心灵之眼的生动图像。这些发现通过识别特定的认知现象和神经基质，与自上而下的感知影响一致，这些影响与神经精神疾病的幻觉有关，从而改进了当前的幻觉模型。