Department of Neuroscience, George Mason University, Fairfax, Virginia; Mental Health Service Line, Washington DC Veterans Affairs Medical Center, Washington, DC; Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21224.
Department of Bioengineering, George Mason University, Fairfax, Virginia.
Neuroscience. 2019 Aug 10;413:108-122. doi: 10.1016/j.neuroscience.2019.06.012. Epub 2019 Jun 20.
One deficit associated with schizophrenia (SZ) is the reduced ability to distinguish self-caused sensations from those due to external sources. This reduced sense of agency (SoA, subjective awareness of control over one's actions) is hypothesized to result from a diminished utilization of internal monitoring signals of self-movement (i.e., efference copy) which subsequently impairs forming and utilizing sensory prediction errors (differences between the predicted and actual sensory consequences resulting from movement). Another important function of these internal monitoring signals is the facilitation of higher-order mechanisms related to motor learning and control. Current predictive-coding models of adaptation postulate that the sensory consequences of motor commands are predicted based on internal action-related information, and that ownership and control of motor behavior is modified in various contexts based on predictive processing. Here, we investigated the connections between SoA and motor adaptation. Schizophrenia patients (SZP, N=30) and non-psychiatric control subjects (HC, N=31) adapted to altered movement visual feedback and applied the motor recalibration to untested contexts (i.e., the spatial generalization). Although adaptation was similar for SZP and controls, the extent of generalization was significantly less for SZP; movement trajectories made by patients to the furthest untrained target (135) before and after adaptation were largely indistinguishable. Interestingly, deficits in generalization were correlated with positive symptoms of psychosis in SZP (e.g., hallucinations). Generalization was also associated with measures of SoA across both SZP and HC, emphasizing the role action awareness plays in motor behavior, and suggesting that misattributing agency, even in HC, manifests in abnormal motor performance.
与精神分裂症（SZ）相关的一个缺陷是，患者区分自身引起的感觉与外部来源引起的感觉的能力降低。这种代理感（SoA，对自身行为控制的主观意识）的降低据推测是由于自我运动的内部监控信号（即传出副本）的利用减少，这随后会损害形成和利用感觉预测误差（由于运动而导致的预测和实际感觉后果之间的差异）的能力。这些内部监控信号的另一个重要功能是促进与运动学习和控制相关的更高阶机制。当前适应的预测编码模型假设，运动指令的感觉后果是基于内部与动作相关的信息进行预测的，并且基于预测处理，对运动行为的所有权和控制会在各种情况下进行修改。在这里，我们研究了 SoA 与运动适应之间的联系。精神分裂症患者（SZP，N=30）和非精神病对照受试者（HC，N=31）适应了改变的运动视觉反馈，并将运动重新校准应用于未经测试的情境（即空间泛化）。尽管 SZP 和对照组的适应相似，但 SZP 的泛化程度明显较低；适应前后，患者到达最远未训练目标（135）的运动轨迹几乎无法区分。有趣的是，SZP 的阳性症状（例如幻觉）与泛化缺陷相关。泛化也与 SZP 和 HC 中 SoA 的测量值相关，强调了行动意识在运动行为中的作用，并表明即使在 HC 中，错误归因于代理，也会表现出异常的运动表现。
