Metacognition is impaired in schizophrenia and is an important predictor of functional outcome, but the underlying neuropathology is not clear. Studies have implicated frontal regions and there is also some evidence that the hippocampus might play a pivotal role, but findings are inconsistent. We set out to more comprehensively investigate the neural underpinnings of insight in first-episode psychosis (FEP) using 2 metacognitive measures (the Beck Cognitive Insight Scale [BCIS]) and a perceptual metacognitive accuracy task alongside structural magnetic resonance imaging (MRI). We measured cortical thickness in insula and frontal regions, hippocampal (including subfield) volumes, hippocampal microstructure (using neurite orientation dispersion and density imaging [NODDI]), and fractional anisotropy in fornix. Relative to controls, FEP showed poorer metacognitive accuracy, thinner cortex in frontal regions and lower fornix integrity. In healthy controls (but not FEP), metacognitive accuracy correlated with cortical thickness in frontal cortex and insula. Conversely, in FEP (but not controls), metacognitive accuracy correlated with hippocampal volume and microstructural indices. Subicular hippocampal subregions were particularly implicated. No structural correlates of BCIS were found. These findings suggest that the neural bases of metacognition might differ in FEP: hippocampal (rather than frontal) integrity seems to be critical. Further, the use of objectively measured metacognitive indices seems to be a more powerful method for understanding the neurocircuitry of metacognition in FEP, which has the potential to inform therapeutic strategies and improve outcome in these patients.

中文翻译：

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初发性精神病中元认知的大脑结构相关性。

元认知在精神分裂症中受损，并且是功能预后的重要预测指标，但潜在的神经病理学尚不清楚。研究涉及额叶区域，也有证据表明海马可能起关键作用，但发现不一致。我们着手使用两种元认知测量方法（贝克认知洞察量表[BCIS]）和具有结构磁共振成像（MRI）的感知元认知准确性任务来更全面地研究首发性精神病（FEP）的知觉的神经基础。我们测量了岛状和额叶区域的皮质厚度，海马区（包括子区域）的体积，海马区的微结构（使用神经突方向分散和密度成像[NODDI]）以及穹ni的分数各向异性。相对于控件，FEP显示较差的元认知准确性，额叶区域的皮层较薄且穹integrity完整性较低。在健康的对照组（但不是FEP）中，元认知的准确性与额叶皮层和岛突的皮层厚度相关。相反，在FEP（而非对照）中，元认知准确度与海马体积和微结构指标相关。特别涉及海马亚区域。没有发现BCIS​​的结构相关性。这些发现表明，元认知的神经基础在FEP中可能有所不同：海马（而不是额叶）完整性似乎很关键。此外，使用客观测量的元认知指标似乎是了解FEP中元认知神经回路的一种更有效的方法，