Université Lille Nord de France, F-59000 Lille, France.
Cereb Cortex. 2013 May;23(5):1108-17. doi: 10.1093/cercor/bhs082. Epub 2012 Apr 24.
The pathophysiology of hallucinations remains mysterious. This research aims to specifically explore the interaction between hallucinations and spontaneous resting-state activity. We used multimodal magnetic resonance imaging during hallucinations occurrence in 20 drug-free adolescents with a "brief psychotic disorder." They were furthermore compared with 20 matched controls at rest or during exteroceptive stimuli. Anatomical and functional symptom-mapping demonstrated reduced cortical thickness and increased blood oxygen level-dependent signal in modality-dependent association sensory cortices during auditory, visual, and multisensory hallucinations. On the contrary, primary-sensory-cortex recruitment was not systematic and was shown to be associated with increased vividness of the hallucinatory experiences. Spatiotemporal activity patterns in the default-mode network (DMN) during hallucinations and symptom-free periods in patients were compared with patterns measured in healthy individuals. A disengagement of the DMN was concomitant to hallucinations, as for exogenous stimulations in healthy participants. Specifically, spatial and temporal instabilities of the DMN correlated with the severity of hallucinations but persisted during symptom-free periods. These results suggest that hallucinatory experiences emerge from a spontaneous DMN withdrawal, providing a convincing model for hallucinations beyond the auditory modality.
幻觉的病理生理学仍然神秘。本研究旨在专门探讨幻觉与自发静息状态活动之间的相互作用。我们在 20 名无药物治疗的青少年出现幻觉期间使用多模态磁共振成像，他们患有“短暂精神病障碍”。此外，他们在休息或接受外感受性刺激期间与 20 名匹配的对照进行了比较。解剖和功能症状映射表明，在听觉、视觉和多感官幻觉期间，与模态相关的感觉皮质中的皮质厚度降低和血氧水平依赖性信号增加。相反，初级感觉皮质的募集不是系统性的，并且与幻觉体验的生动度增加有关。将患者在幻觉和无症状期间的默认模式网络 (DMN) 的时空活动模式与健康个体测量的模式进行比较。DMN 的脱离伴随着幻觉，就像健康参与者的外源性刺激一样。具体而言，DMN 的空间和时间不稳定性与幻觉的严重程度相关，但在无症状期间持续存在。这些结果表明，幻觉是从自发的 DMN 撤出中产生的，为超越听觉模式的幻觉提供了一个令人信服的模型。
