Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, University Medical Center Utrecht, Room A.01.126, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.
Schizophr Res. 2012 Dec;142(1-3):237-43. doi: 10.1016/j.schres.2012.09.017. Epub 2012 Oct 23.
The default-mode network (DMN) of the brain shows highly coherent intrinsic activity in healthy subjects and is implicated in self-referential processing important for social cognitive functioning. Schizophrenia patients show abnormal resting-state connectivity within the DMN and this aberrant connectivity is thought to contribute to difficulties in self-referential and introspective processing. Subjects at increased genetic risk of developing schizophrenia, including unaffected siblings of patients, also exhibit brain abnormalities and impaired social cognitive processing. However, it is unclear whether resting-state connectivity within the DMN is abnormal in these subjects. Here, we investigate resting-state DMN connectivity in siblings and whether this is related to the functioning of the network during self-referential processing. Brain activity was measured using functional MRI in 25 unaffected siblings of patients with schizophrenia and 25 healthy controls during an 8-minute resting-state period and during a self-referential processing task in which the subjects had to indicate whether a trait adjective (e.g. "lazy") described their personality (self-referential condition) or whether the trait was socially desirable (non-referential condition). Compared with controls, siblings showed exaggerated connectivity during resting-state between the midline areas of the DMN. Moreover, they failed to adequately modulate connectivity between these areas during self-referential processing. No abnormalities in activation during self-referential processing were observed. These findings suggest that subjects at increased genetic risk of developing schizophrenia exhibit abnormal intrinsic connectivity within the midline DMN and that this is associated with aberrant interactions between these regions during self-referential processing.
大脑的默认模式网络 (DMN) 在健康受试者中表现出高度一致的内在活动，并且与自我参照处理有关，这对于社会认知功能很重要。精神分裂症患者在 DMN 内显示出异常的静息状态连接，这种异常连接被认为导致自我参照和内省处理困难。具有发展为精神分裂症遗传风险增加的受试者，包括患者的未受影响的兄弟姐妹，也表现出大脑异常和社会认知处理受损。然而，目前尚不清楚这些受试者的 DMN 内静息状态连接是否异常。在这里，我们研究了兄弟姐妹的 DMN 静息状态连接，以及这种连接是否与自我参照处理过程中网络的功能有关。在 8 分钟的静息状态期间和在自我参照处理任务期间，使用功能磁共振成像测量了 25 名精神分裂症患者的未受影响的兄弟姐妹和 25 名健康对照者的大脑活动，在该任务中，受试者必须指示一个特质形容词（例如“懒惰”）是否描述了他们的个性（自我参照条件）或特质是否具有社交吸引力（非参照条件）。与对照组相比，兄弟姐妹在 DMN 的中线区域之间在静息状态下显示出过度的连接。此外，他们在自我参照处理过程中无法充分调节这些区域之间的连接。在自我参照处理期间没有观察到激活的异常。这些发现表明，具有发展为精神分裂症遗传风险增加的受试者表现出中线 DMN 内异常的内在连接，并且这与这些区域之间的异常相互作用有关。
