Culbreth Adam J, Kasanova Zuzana, Ross Thomas J, Salmeron Betty J, Gold James M, Stein Elliot A, Waltz James A
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA.
Leuven Research & Development Spin-off & Innovation Unit, KU Leuven, Waaistraat 6-Box 5105, 3000 Leuven, Belgium.
Brain Sci. 2021 Dec 6;11(12):1610. doi: 10.3390/brainsci11121610.
Recent evidence suggests that the aberrant signaling of salience is associated with psychotic illness. Salience, however, can take many forms in task environments. For example, salience may refer to any of the following: (1) the valence of an outcome, (2) outcomes that are unexpected, called reward prediction errors (PEs), or (3) cues associated with uncertain outcomes. Here, we measure brain responses to different forms of salience in the context of a passive PE-signaling task, testing whether patients with schizophrenia (SZ) showed aberrant signaling of particular types of salience. We acquired event-related MRI data from 29 SZ patients and 23 controls during the performance of a passive outcome prediction task. Across groups, we found that the anterior insula and posterior parietal cortices were activated to multiple different types of salience, including PE magnitude and heightened levels of uncertainty. However, BOLD activation to salient events was not significantly different between patients and controls in many regions, including the insula, posterior parietal cortices, and default mode network nodes. Such results suggest that deficiencies in salience processing in SZ may not result from an impaired ability to signal salience , but instead the ability to use such signals to guide future actions. Notably, no between-group differences were observed in BOLD signal changes associated with PE-signaling in the striatum. However, positive symptom severity was found to significantly correlate with the magnitudes of salience contrasts in default mode network nodes. Our results suggest that, in an observational environment, SZ patients may show an intact ability to activate striatal and cortical regions to rewarding and non-rewarding salient events. Furthermore, reduced deactivation of a hypothesized default mode network node for SZ participants with high levels of positive symptoms, following salient events, point to abnormalities in interactions of the salience network with other brain networks, and their potential importance to positive symptoms.
近期证据表明，显著性的异常信号传导与精神疾病有关。然而，在任务环境中，显著性可以有多种形式。例如，显著性可能指以下任何一种：(1) 结果的效价，(2) 意外的结果，称为奖励预测误差 (PEs)，或 (3) 与不确定结果相关的线索。在此，我们在被动PE信号任务的背景下测量大脑对不同形式显著性的反应，测试精神分裂症 (SZ) 患者是否表现出特定类型显著性的异常信号传导。我们在29名SZ患者和23名对照执行被动结果预测任务期间获取了事件相关的MRI数据。在所有组中，我们发现前脑岛和顶叶后皮质对多种不同类型的显著性有激活反应，包括PE大小和更高水平的不确定性。然而，在包括脑岛、顶叶后皮质和默认模式网络节点在内的许多区域，患者和对照对显著事件的BOLD激活没有显著差异。这些结果表明，SZ患者显著性处理缺陷可能不是由于显著性信号传导能力受损，而是由于利用此类信号指导未来行动的能力受损。值得注意的是，在纹状体中，与PE信号传导相关的BOLD信号变化未观察到组间差异。然而，发现阳性症状严重程度与默认模式网络节点中显著性对比的大小显著相关。我们的结果表明，在观察环境中，SZ患者可能表现出激活纹状体和皮质区域以应对奖励性和非奖励性显著事件的完整能力。此外，对于具有高水平阳性症状的SZ参与者，在显著事件后，假设的默认模式网络节点的去激活减少，这表明显著性网络与其他脑网络相互作用存在异常，以及它们对阳性症状的潜在重要性。
