Fromm Sophie, Katthagen Teresa, Deserno Lorenz, Heinz Andreas, Kaminski Jakob, Schlagenhauf Florian
Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health CCM, Department of Psychiatry and Neuroscience | CCM, NeuroCure Clinical Research Center, Berlin, Germany.
Charité - Universitätsmedizin Berlin, Einstein Center for Neurosciences Berlin, Berlin, Germany.
Schizophr Bull Open. 2022 Dec 14;4(1):sgac074. doi: 10.1093/schizbullopen/sgac074. eCollection 2023 Jan.
Current frameworks propose that delusions result from aberrant belief updating due to altered prediction error (PE) signaling and misestimation of environmental volatility. We aimed to investigate whether behavioral and neural signatures of belief updating are specifically related to the presence of delusions or generally associated with manifest schizophrenia.
Our cross-sectional design includes human participants ([female/male] = 66[25/41]), stratified into four groups: healthy participants with minimal ( = 22) or strong delusional-like ideation ( = 18), and participants with diagnosed schizophrenia with minimal ( = 13) or strong delusions ( = 13), resulting in a 2 × 2 design, which allows to test for the effects of delusion and diagnosis. Participants performed a reversal learning task with stable and volatile task contingencies during fMRI scanning. We formalized learning with a hierarchical Gaussian filter model and conducted model-based fMRI analysis regarding beliefs of outcome uncertainty and volatility, precision-weighted PEs of the outcome- and the volatility-belief.
Patients with schizophrenia as compared to healthy controls showed lower accuracy and heightened choice switching, while delusional ideation did not affect these measures. Participants with delusions showed increased precision-weighted PE-related neural activation in fronto-striatal regions. People with diagnosed schizophrenia overestimated environmental volatility and showed an attenuated neural representation of volatility in the anterior insula, medial frontal and angular gyrus.
Delusional beliefs are associated with altered striatal PE-signals. Juxtaposing, the potentially unsettling belief that the environment is constantly changing and weaker neural encoding of this subjective volatility seems to be associated with manifest schizophrenia, but not with the presence of delusional ideation.
当前的理论框架认为，妄想是由于预测误差（PE）信号改变和对环境波动性的错误估计导致信念更新异常所致。我们旨在研究信念更新的行为和神经特征是否与妄想的存在有特定关联，还是与明显的精神分裂症普遍相关。
我们的横断面设计纳入了人类参与者（[女性/男性]=66[25/41]），分为四组：有轻微（=22）或强烈类妄想观念的健康参与者（=18），以及被诊断为精神分裂症且有轻微（=13）或强烈妄想的参与者（=13），形成2×2设计，可用于测试妄想和诊断的影响。参与者在功能磁共振成像（fMRI）扫描期间执行了一个具有稳定和波动任务条件的反转学习任务。我们用分层高斯滤波器模型对学习进行形式化，并对结果不确定性和波动性的信念、结果信念和波动性信念的精确加权预测误差进行基于模型的fMRI分析。
与健康对照组相比，精神分裂症患者表现出较低的准确性和更高的选择转换率，而妄想观念并未影响这些指标。有妄想的参与者在额纹状体区域显示出与精确加权预测误差相关的神经激活增加。被诊断为精神分裂症的人高估了环境波动性，并且在前岛叶、内侧额叶和角回中波动性的神经表征减弱。
妄想信念与纹状体预测误差信号改变有关。相比之下，认为环境不断变化这一潜在令人不安的信念以及这种主观波动性的较弱神经编码似乎与明显的精神分裂症有关，但与妄想观念的存在无关。
