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Hallucinations both in and out of context: An Active Inference Account
- Source :
- PLoS ONE, Vol 14, Iss 8, p e0212379 (2019), PLoS ONE
- Publication Year :
- 2019
- Publisher :
- Cold Spring Harbor Laboratory, 2019.
-
Abstract
- 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.
- Subjects :
- Prodromal Period
Hallucinations
Science
Social Sciences
Inference
Context (language use)
Sensory system
Models, Psychological
050105 experimental psychology
03 medical and health sciences
0302 clinical medicine
Hearing
Mental Health and Psychiatry
Medicine and Health Sciences
medicine
Humans
Psychology
Speech
0501 psychology and cognitive sciences
Free Energy
Physics
Healthy population
05 social sciences
Biology and Life Sciences
Psychoses
Linguistics
Probability Theory
Probability Distribution
medicine.disease
Hallucinating
Schizophrenia
Physical Sciences
Thermodynamics
Medicine
Sensory Perception
Mathematics
030217 neurology & neurosurgery
Sentence
Research Article
Neuroscience
Cognitive psychology
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- PLoS ONE, Vol 14, Iss 8, p e0212379 (2019), PLoS ONE
- Accession number :
- edsair.doi.dedup.....1d5a1c8109df683fa6ca5532be097d0a