Distinct processing of ambiguous speech in people with non-clinical auditory verbal hallucinations
Distinct processing of ambiguous speech in people with non-clinical auditory verbal hallucinations
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DOI：
10.1093/brain/awx206
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发表时间：
2017-09-01
期刊：
影响因子：
14.5
通讯作者：
Scott, Sophie K.
中科院分区：
文献类型：
--
作者：
Alderson-Day, Ben;Lima, Cesar F.;Scott, Sophie K.
听觉言语幻觉（听到声音）通常与精神病有关，但少数普通人群也经常经历它们，并且没有痛苦。这种“非临床”的经验提供了一个罕见的和独特的机会，研究幻觉除了混淆的临床因素，从而允许识别特定的机制。最近的理论认为幻觉是由于先前的期望和感官信息的不平衡造成的，但这种不平衡是否也影响了知觉过程仍然是未知的。我们第一次检查了没有精神病的人谁经常听到的声音含糊的语言的皮层处理。12个非临床的语音听众和17个匹配的对照完成了功能磁共振成像扫描，同时被动地听退化的语音（“正弦波”语音），这是潜在的可理解或不可理解的。语音听众报告说，认识到存在的语音刺激之前，控制，并明确告知其可理解性。在两组中，可理解的正弦波语音参与了典型的左偏侧语音处理网络。然而，值得注意的是，听声音的人在背侧前扣带皮层和上级额回表现出比对照组更强的可理解性反应。这表明，加强参与的注意力和感觉运动过程，选择性地当语音是潜在的可理解的。总之，这些行为和神经研究结果表明，有幻觉经历的人对有意义的听觉刺激表现出不同的反应。对先验知识和期望的更大权重可能会导致这些个体的非真实听觉，但它也可能自发地促进需要这种知识的感知处理。这对临床和非临床人群中幻觉的理解具有影响，并且与当前精神病的“预测处理”理论一致。
Auditory verbal hallucinations (hearing voices) are typically associated with psychosis, but a minority of the general population also experience them frequently and without distress. Such 'non-clinical' experiences offer a rare and unique opportunity to study hallucinations apart from confounding clinical factors, thus allowing for the identification of symptom-specific mechanisms. Recent theories propose that hallucinations result from an imbalance of prior expectation and sensory information, but whether such an imbalance also influences auditory-perceptual processes remains unknown. We examine for the first time the cortical processing of ambiguous speech in people without psychosis who regularly hear voices. Twelve non-clinical voice-hearers and 17 matched controls completed a functional magnetic resonance imaging scan while passively listening to degraded speech ('sine-wave' speech), that was either potentially intelligible or unintelligible. Voice-hearers reported recognizing the presence of speech in the stimuli before controls, and before being explicitly informed of its intelligibility. Across both groups, intelligible sine-wave speech engaged a typical left-lateralized speech processing network. Notably, however, voice-hearers showed stronger intelligibility responses than controls in the dorsal anterior cingulate cortex and in the superior frontal gyrus. This suggests an enhanced involvement of attention and sensorimotor processes, selectively when speech was potentially intelligible. Altogether, these behavioural and neural findings indicate that people with hallucinatory experiences show distinct responses to meaningful auditory stimuli. A greater weighting towards prior knowledge and expectation might cause non-veridical auditory sensations in these individuals, but it might also spontaneously facilitate perceptual processing where such knowledge is required. This has implications for the understanding of hallucinations in clinical and non-clinical populations, and is consistent with current 'predictive processing' theories of psychosis.