Hallucinations both in and out of context: An active inference account
Hallucinations both in and out of context: An active inference account
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DOI：
10.1371/journal.pone.0212379
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发表时间：
2019-08-20
期刊：
影响因子：
3.7
通讯作者：
Friston, Karl
中科院分区：
文献类型：
--
作者：
Benrimoh, David;Parr, Thomas;Friston, Karl
幻听，包括幻听（AVH），在健康人群和精神分裂症等精神病（通常在前驱期后发生）中都会发生。此外，幻觉可以是上下文中的（它们可以与环境一致，例如当一个人幻觉一个已经重复多次的句子的结尾时），也可以是脱离上下文的（例如与精神分裂症相关的奇异幻觉）。在之前的工作中，我们引入了一种基于主动推理（马尔可夫决策过程）表述的错误（肯定）推理的幻觉模型。在这项工作中，我们扩展了这个模型以包含内容，以揭示上下文内和上下文外幻觉背后的计算机制。在主动推理中，感觉信息用于消除有关感觉原因的替代假设的歧义。感官信息与先前的信念相平衡，当这种平衡向先前的信念倾斜时，就会出现幻觉。我们表明，当（模拟的）受试者无法使用感官信息来纠正先前关于听到声音的信念，但关于内容的信念（即句子的顺序）仍然准确时，就会出现上下文幻觉。当产生幻觉的受试者对状态转换也有不准确的信念时，就会出现断章取义的幻觉。即他们的幻觉言语内容是混乱的。请注意，这种情况下的脱离上下文的幻觉并不是指对上下文的推断，而是指当感官证据的置信度或精确度降低时出现的错误知觉推断。此外，对状态转换有不准确信念但使用感觉信息的完整能力的受试者不会产生幻觉，并且会让人想起前驱期患者。这项工作展示了可能构成从健康人群到精神病状态的幻觉体验范围的不同计算机制。
Hallucinations, including auditory verbal hallucinations (AVH), occur in both the healthy population and in psychotic conditions such as schizophrenia (often developing after a prodromal period). In addition, hallucinations can be in-context (they can be consistent with the environment, such as when one hallucinates the end of a sentence that has been repeated many times), or out-of-context (such as the bizarre hallucinations associated with schizophrenia). In previous work, we introduced a model of hallucinations as false (positive) inferences based on a (Markov decision process) formulation of active inference. In this work, we extend this model to include content-to disclose the computational mechanisms behind in-and out-of-context hallucinations. In active inference, sensory information is used to disambiguate alternative hypotheses about the causes of sensations. Sensory information is balanced against prior beliefs, and when this balance is tipped in the favor of prior beliefs, hallucinations can occur. We show that in-context hallucinations arise when (simulated) subjects cannot use sensory information to correct prior beliefs about hearing a voice, but beliefs about content (i.e. the sequential order of a sentence) remain accurate. When hallucinating subjects also have inaccurate beliefs about state transitions, out-of-context hallucinations occur; i.e. their hallucinated speech content is disordered. Note that out-of-context hallucinations in this setting does not refer to inference about context, but rather to false perceptual inference that emerges when the confidence in-or precision of-sensory evidence is reduced. Furthermore, subjects with inaccurate beliefs about state transitions but an intact ability to use sensory information do not hallucinate and are reminiscent of prodromal patients. This work demonstrates the different computational mechanisms that may underlie the spectrum of hallucinatory experience-from the healthy population to psychotic states.