Ford Judith M, Mathalon Daniel H
Department of Psychiatry & Behavioral Sciences Stanford University School of Medicine, and Psychiatry Service, Veterans Affairs Medical Center, Palo Alto, USA.
J Psychiatr Res. 2004 Jan;38(1):37-46. doi: 10.1016/s0022-3956(03)00095-5.
Failure of corollary discharge, a mechanism for distinguishing self-generated from externally-generated percepts, has been posited to underlie certain positive symptoms of schizophrenia, including auditory hallucinations. Although originally described in the visual system, corollary discharge may exist in the auditory system, whereby signals from motor speech commands prepare auditory cortex for self-generated speech. While associated with sensorimotor systems, it might also apply to inner speech or thought, regarded as our most complex motor act. We had four aims in the studies summarized in this paper: (1) to demonstrate the corollary discharge phenomenon during talking and inner speech in human volunteers using event-related brain potentials (ERPs), (2) to demonstrate that the corollary discharge is abnormal in patients with schizophrenia, (3) to demonstrate the role of frontal speech areas in the corollary discharge during talking, and (4) to relate the dysfunction of the corollary discharge in schizophrenia to auditory hallucinations. Using EEG and ERP measures, we addressed each aim in patients with schizophrenia (DSM IV) and healthy control subjects. The N1 component of the ERP reflected dampening of auditory cortex responsivity during talking and inner speech in control subjects but not in patients. EEG measures of coherence indicated inter-dependence of activity in the frontal speech production and temporal speech reception areas during talking in control subjects, but not in patients, especially those who hallucinated. These data suggest that a corollary discharge from frontal areas where thoughts are generated fails to alert auditory cortex that they are self-generated, leading to the misattribution of inner speech to external sources and producing the experience of auditory hallucinations.
伴随放电的缺失被认为是精神分裂症某些阳性症状（包括幻听）的潜在原因，伴随放电是一种区分自我产生的感知和外部产生的感知的机制。尽管最初是在视觉系统中描述的，但伴随放电可能存在于听觉系统中，来自运动言语指令的信号会使听觉皮层为自我产生的言语做好准备。虽然与感觉运动系统相关，但它也可能适用于内心言语或思维，而内心言语或思维被视为我们最复杂的运动行为。在本文总结的研究中，我们有四个目标：（1）使用事件相关脑电位（ERP）在人类志愿者的说话和内心言语过程中证明伴随放电现象；（2）证明精神分裂症患者的伴随放电异常；（3）证明额叶言语区域在说话过程中伴随放电中的作用；（4）将精神分裂症中伴随放电功能障碍与幻听联系起来。我们使用脑电图（EEG）和ERP测量方法，在精神分裂症患者（DSM-IV）和健康对照受试者中实现了每个目标。ERP的N1成分反映了对照受试者在说话和内心言语过程中听觉皮层反应性的减弱，而在患者中则没有。EEG相干性测量表明，对照受试者在说话时额叶言语产生区域和颞叶言语接收区域的活动相互依赖，而在患者中则不然，尤其是那些有幻觉的患者。这些数据表明，来自产生思维的额叶区域的伴随放电未能提醒听觉皮层这些思维是自我产生的，导致内心言语被错误归因于外部来源，并产生幻听体验。
