Frith C
Wellcome Department of Cognitive Neurology, Institute of Neurology, London, U.K.
Philos Trans R Soc Lond B Biol Sci. 1996 Oct 29;351(1346):1505-12. doi: 10.1098/rstb.1996.0136.
Many patients with schizophrenia report hallucinations in which they hear voices talking to them or about them. Behavioural and physiological studies show that this experience is associated with processes occurring in auditory language systems associated with both the production and the reception of speech. I propose that hallucinations are experienced because patients have difficulty in distinguishing sensations caused by their own actions from those that arise from external influences. This distinction can be made by predicting the sensations that will result from executive commands (forward modelling). If the predicted sensation matches the actual sensation then no outside influences have occurred and perception of change can be 'cancelled'. At the physiological level this mechanism depends upon interactions between the prefrontal areas where the executive commands originate and posterior brain regions concerned with the resultant sensations. Evidence from functional brain imaging confirms that interactions between prefrontal (executive) areas and auditory association areas are abnormal in schizophrenia. However, this account needs to be extended before we can understand why patients experience the voices as emanating, not just from an external source, but from agents who are trying to influence their behaviour. Recent imaging studies suggest that medial prefrontal cortex is engaged when we think about other people, but the precise nature of the interaction of this brain area with other regions remains to be established.
许多精神分裂症患者报告称有幻觉，即他们听到有声音与他们交谈或谈论他们。行为学和生理学研究表明，这种体验与听觉语言系统中发生的过程有关，这些过程与言语的产生和接收都相关。我提出，患者之所以会有幻觉体验，是因为他们难以区分由自身行为引起的感觉和由外部影响产生的感觉。这种区分可以通过预测执行指令（正向建模）所产生的感觉来实现。如果预测的感觉与实际感觉相符，那么就没有外部影响发生，对变化的感知就可以“消除”。在生理层面，这种机制依赖于执行指令产生的前额叶区域与处理相应感觉的后脑区域之间的相互作用。功能性脑成像的证据证实，前额叶（执行）区域与听觉联合区域之间的相互作用在精神分裂症中是异常的。然而，在我们能够理解为什么患者会将声音体验为不仅来自外部来源，而且来自试图影响他们行为的主体之前，这个解释还需要进一步扩展。最近的成像研究表明，当我们想到其他人时，内侧前额叶皮层会被激活，但这个脑区与其他区域相互作用的确切性质仍有待确定。
