Department of Medicine, Dentistry & Health Sciences, Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia.
Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia.
Schizophr Bull. 2021 Jul 8;47(4):1039-1047. doi: 10.1093/schbul/sbaa188.
Recent theories in computational psychiatry propose that unusual perceptual experiences and delusional beliefs may emerge as a consequence of aberrant inference and disruptions in sensory learning. The current study investigates these theories and examines the alterations that are specific to schizophrenia spectrum disorders vs those that occur as psychotic phenomena intensify, regardless of diagnosis. We recruited 66 participants: 22 schizophrenia spectrum inpatients, 22 nonpsychotic inpatients, and 22 nonclinical controls. Participants completed the reversal oddball task with volatility manipulated. We recorded neural responses with electroencephalography and measured behavioral errors to inferences on sound probabilities. Furthermore, we explored neural dynamics using dynamic causal modeling (DCM). Attenuated prediction errors (PEs) were specifically observed in the schizophrenia spectrum, with reductions in mismatch negativity in stable, and P300 in volatile, contexts. Conversely, aberrations in connectivity were observed across all participants as psychotic phenomena increased. DCM revealed that impaired sensory learning behavior was associated with decreased intrinsic connectivity in the left primary auditory cortex and right inferior frontal gyrus (IFG); connectivity in the latter was also reduced with greater severity of psychotic experiences. Moreover, people who experienced more hallucinations and psychotic-like symptoms had decreased bottom-up and increased top-down frontotemporal connectivity, respectively. The findings provide evidence that reduced PEs are specific to the schizophrenia spectrum, but deficits in brain connectivity are aligned on the psychosis continuum. Along the continuum, psychotic experiences were related to an aberrant interplay between top-down, bottom-up, and intrinsic connectivity in the IFG during sensory uncertainty. These findings provide novel insights into psychosis neurocomputational pathophysiology.
最近的计算精神病学理论提出，异常的知觉体验和妄想信念可能是由于异常推理和感觉学习中断而出现的。本研究调查了这些理论，并研究了精神分裂症谱系障碍特有的改变，以及无论诊断如何，随着精神病现象加剧而发生的改变。我们招募了 66 名参与者：22 名精神分裂症谱系住院患者、22 名非精神病住院患者和 22 名非临床对照者。参与者完成了具有波动性操纵的反转奇数任务。我们记录了脑电图的神经反应，并测量了对声音概率推断的行为错误。此外，我们使用动态因果建模（DCM）探索了神经动力学。在精神分裂症谱系中，特别是观察到衰减的预测误差（PE），在稳定的情况下，失匹配负波（MMN）减少，在易变的情况下，P300 减少。相反，随着精神病现象的增加，所有参与者都观察到连接异常。DCM 显示，感觉学习行为受损与左初级听觉皮层和右额下回（IFG）的内在连接减少有关；随着精神病体验的严重程度增加，后者的连接也减少了。此外，经历更多幻觉和类精神病症状的人，自上而下和自下而上的额颞叶连接分别减少和增加。这些发现提供了证据表明，PE 的减少是精神分裂症谱系特有的，但大脑连接的缺陷与精神病连续统上是一致的。在连续统中，在感觉不确定期间，IFG 中自上而下、自下而上和内在连接的异常相互作用与精神病体验有关。这些发现为精神病神经计算病理生理学提供了新的见解。
