Laboratory of Cognitive Neuroscience, Neuro-X Institute & Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland.
University Grenoble Alpes, University Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France.
Psychol Med. 2024 Feb;54(3):569-581. doi: 10.1017/S0033291723002222. Epub 2023 Oct 2.
Inducing hallucinations under controlled experimental conditions in non-hallucinating individuals represents a novel research avenue oriented toward understanding complex hallucinatory phenomena, avoiding confounds observed in patients. Auditory-verbal hallucinations (AVH) are one of the most common and distressing psychotic symptoms, whose etiology remains largely unknown. Two prominent accounts portray AVH either as a deficit in auditory-verbal self-monitoring, or as a result of overly strong perceptual priors.
In order to test both theoretical models and evaluate their potential integration, we developed a robotic procedure able to induce self-monitoring perturbations (consisting of sensorimotor conflicts between poking movements and corresponding tactile feedback) and a perceptual prior associated with otherness sensations (i.e. feeling the presence of a non-existing another person).
Here, in two independent studies, we show that this robotic procedure led to AVH-like phenomena in healthy individuals, quantified as an increase in false alarm rate in a voice detection task. Robotically-induced AVH-like sensations were further associated with delusional ideation and to both AVH accounts. Specifically, a condition with stronger sensorimotor conflicts induced more AVH-like sensations (self-monitoring), while, in the otherness-related experimental condition, there were more AVH-like sensations when participants were detecting other-voice stimuli, compared to detecting self-voice stimuli (strong-priors).
By demonstrating an experimental procedure able to induce AVH-like sensations in non-hallucinating individuals, we shed new light on AVH phenomenology, thereby integrating self-monitoring and strong-priors accounts.
在非幻觉个体中诱导受控制的实验性幻觉代表了一种理解复杂幻觉现象的新研究途径，避免了患者中观察到的混杂因素。听觉幻觉（AVH）是最常见和最令人痛苦的精神病症状之一，其病因仍很大程度上未知。两种突出的解释要么将 AVH 描绘为听觉言语自我监测的缺陷，要么将其描绘为过度强烈的知觉先验的结果。
为了测试这两种理论模型并评估它们的潜在整合，我们开发了一种能够诱导自我监测干扰（由戳动和相应触觉反馈之间的感觉运动冲突组成）和与他异性感觉相关的知觉先验（即感觉不存在的另一个人的存在）的机器人程序。
在这里，在两项独立的研究中，我们表明，这种机器人程序导致了健康个体中类似于 AVH 的现象，表现在语音检测任务中的错误警报率增加。机器人诱导的类似于 AVH 的感觉进一步与妄想观念以及两种 AVH 解释相关。具体来说，具有更强感觉运动冲突的条件会引起更多类似于 AVH 的感觉（自我监测），而在与他异性相关的实验条件下，与检测自我声音刺激相比，当参与者检测到他人声音刺激时，会出现更多类似于 AVH 的感觉（强先验）。
通过证明能够在非幻觉个体中诱导类似于 AVH 的感觉的实验程序，我们为 AVH 现象学提供了新的视角，从而整合了自我监测和强先验解释。
