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ABSTRACT: Background
There is increasing evidence for predictive coding theories of psychosis, which state that hallucinations arise from abnormal perceptual priors or biases. However, psychological processes that foster abnormal priors/biases in patients suffering hallucinations have been largely unexplored. The widely recognized relationship between affective disorders and psychosis suggests a role for mood and emotion.Methods
Thirty-six patients with dementia with Lewy bodies (DLB), a representative condition associated with psychosis of neurological origin, and 12 patients with Alzheimer's disease (AD) were enrolled. After an experimental mood induction, the participants underwent the pareidolia test, in which visual hallucination-like illusions were evoked and measured.Results
In DLB patients, the number of pareidolic illusions was doubled under negative mood compared to that under neutral mood. In AD patients, there was no significant difference in the number of pareidolic responses between negative and neutral mood conditions. A signal detection theory analysis demonstrated that the observed affective modulation of pareidolic illusions was mediated through heightened perceptual bias, not sensory deterioration.Conclusions
The current findings demonstrated that abnormal perceptual priors in psychotic false perception have an affective nature, which we suggest are a type of cognitive feeling that arises in association with perception and cognition.
SUBMITTER: Watanabe H
PROVIDER: S-EPMC5983458 | biostudies-literature | 2018
REPOSITORIES: biostudies-literature
Watanabe Hiroyuki H Nishio Yoshiyuki Y Mamiya Yasuyuki Y Narita Wataru W Iizuka Osamu O Baba Toru T Takeda Atsushi A Shimomura Tatsuo T Mori Etsuro E
PloS one 20180601 6
<h4>Background</h4>There is increasing evidence for predictive coding theories of psychosis, which state that hallucinations arise from abnormal perceptual priors or biases. However, psychological processes that foster abnormal priors/biases in patients suffering hallucinations have been largely unexplored. The widely recognized relationship between affective disorders and psychosis suggests a role for mood and emotion.<h4>Methods</h4>Thirty-six patients with dementia with Lewy bodies (DLB), a r ...[more]