However Aifred was not involved in this work nor does this work pertain to Aifred's area of interest. KJF is a Wellcome Principal Research Fellow (Ref: 088130/Z/09/Z).Ĭompeting interests: DB is a shareholder and board member of Aifred Health, a mental health AI company. RAA was supported by an NIHR University College London Hospitals Biomedical Research Centre Postgraduate Fellowship and is now an MRC Skills Development Fellow (MR/S007806/1). TP is supported by the Rosetrees Trust (Award Number 173346). įunding: DB is supported by a Richard and Edith Strauss Fellowship (McGill University) and the Fonds de Recherche du Quebec- Santé (FRQS). The scripts for this simulation can be found at the following GitHub account. This is open-access software provided and maintained by the Wellcome Centre for Human Neuroimaging and can be accessed here. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All simulations were run using the DEM toolbox included in the SPM12 package. ![]() Received: JanuAccepted: AugPublished: August 20, 2019Ĭopyright: © 2019 Benrimoh et al. PLoS ONE 14(8):Įditor: Constantine Dovrolis, Georgia Institute of Technology, UNITED STATES This work demonstrates the different computational mechanisms that may underlie the spectrum of hallucinatory experience–from the healthy population to psychotic states.Ĭitation: Benrimoh D, Parr T, Adams RA, Friston K (2019) Hallucinations both in and out of context: An active inference account. 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. 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. their hallucinated speech content is disordered. When hallucinating subjects also have inaccurate beliefs about state transitions, out-of-context hallucinations occur i.e. ![]() the sequential order of a sentence) remain accurate. 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. Sensory information is balanced against prior beliefs, and when this balance is tipped in the favor of prior beliefs, hallucinations can occur. ![]() ![]() In active inference, sensory information is used to disambiguate alternative hypotheses about the causes of sensations. In this work, we extend this model to include content–to disclose the computational mechanisms behind in- and out-of-context hallucinations. In previous work, we introduced a model of hallucinations as false (positive) inferences based on a (Markov decision process) formulation of active inference. 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). 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).
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