From the Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Psychiatry and Psychotherapy CCM, Berlin, Germany (Fukuda, Katthagen, Kaminski, Heinz, Schlagenhauf); the Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University of Leipzig, Leipzig, Germany (Deserno); Department of Neurology, Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany (Deserno, Kaminski, Schlagenhauf); the Columbia University College of Physicians and Surgeons, New York, NY (Shayegan); and the Berlin Institute of Health, Berlin, Germany (Kaminski).
J Psychiatry Neurosci. 2019 May 1;44(3):195-204. doi: 10.1503/jpn.180043.
Working-memory impairment is a core cognitive dysfunction in people with schizophrenia and people at mental high risk. Recent imaging studies on working memory have suggested that abnormalities in prefrontal activation and in connectivity between the frontal and parietal regions could be neural underpinnings of the different stages of psychosis. However, it remains to be explored whether comparable alterations are present in people with subclinical levels of psychosis, as experienced by a small proportion of the general population who neither seek help nor show constraints in daily functioning.
We compared 24 people with subclinical high delusional ideation and 24 people with low delusional ideation. Both groups performed an n-back working-memory task during functional magnetic resonance imaging. We characterized frontoparietal effective connectivity using dynamic causal modelling.
Compared to people who had low delusional ideation, people with high delusional ideation showed a significant increase in dorsolateral prefrontal activation during the working-memory task, as well as reduced working-memory-dependent parietofrontal effective connectivity in the left hemisphere. Group differences were not evident at the behavioural level.
The current experimental design did not distinguish among the working-memory subprocesses; it remains unexplored whether differences in connectivity exist at that level.
These findings suggest that alterations in the working-memory network are also present in a nonclinical population with psychotic experiences who do not display cognitive deficits. They also suggest that alterations in working-memory-dependent connectivity show a putative continuity along the spectrum of psychotic symptoms.
工作记忆损伤是精神分裂症患者和处于高心理风险人群的核心认知功能障碍。最近关于工作记忆的影像学研究表明，前额叶激活和额顶区域之间连接的异常可能是精神病不同阶段的神经基础。然而，在经历了一小部分人群的亚临床精神病水平，即既不寻求帮助也不在日常生活中表现出限制的人群中，是否存在类似的改变仍有待探讨。
我们比较了 24 名有亚临床高度妄想观念的人和 24 名妄想观念较低的人。两组人都在功能磁共振成像期间进行 n-back 工作记忆任务。我们使用动态因果建模来描述额顶叶的有效连接。
与妄想观念较低的人相比，妄想观念较高的人在工作记忆任务中表现出背外侧前额叶激活的显著增加，以及左半球的工作记忆依赖的顶额叶有效连接减少。在行为水平上没有观察到组间差异。
当前的实验设计没有区分工作记忆的子过程；尚不清楚在该水平上是否存在连接差异。
这些发现表明，在没有认知缺陷的有精神病体验的非临床人群中，工作记忆网络的改变也存在。它们还表明，工作记忆依赖的连接的改变在精神病症状的谱上表现出一种潜在的连续性。
