N-methyl-d-aspartate receptor hypofunction causes recurrent and transient failures of perceptual inference.

Perception integrates external sensory signals with internal predictions that reflect prior knowledge about the world. Previous research suggests that this integration is governed by slow alternations between an external mode, driven by sensory signals, and an internal mode, shaped by prior knowledge. Using a double-blind, placebo-controlled, cross-over experiment in healthy human participants, we investigated the effects of the N-Methyl-D-aspartate receptor (NMDAR) antagonist S-ketamine on the balance between external and internal modes.

Revisiting the Defeatist Performance Belief Scale in Adults With Schizophrenia and Youth at Clinical High-Risk for Psychosis: A Comprehensive Psychometric Analysis.

Background And Hypothesis: In accordance with the Cognitive Model of Negative Symptoms, defeatist performance beliefs (DPBs) are an important psychosocial mechanism of negative symptoms in schizophrenia-spectrum groups. DPBs are also mediators of negative symptom improvement in clinical trials. Despite the clinical significance of DPBs and their inclusion as a mechanism of change measure in clinical trials, the psychometric properties of the DPB scale have not been examined in any schizophrenia-spectrum group.

Delusional Unreality and Predictive Processing.

Background: Phenomenological psychopathologists have recently highlighted how people with delusions experience multiple realities (delusional and non-delusional) and have suggested this double bookkeeping cannot be explained via predictive processing. Here, we present data from Kamin blocking and extinction learning that show how predictive processing might, in principle, explain a pervasive sense of dual reality.

Methods: This cross-sectional study involved three participant groups: patients with schizophrenia (SZ; n=42), healthy participants with elevated esoteric beliefs (EEB; clairaudient psychics; n=31), and heathy controls (with neither illness nor significant delusional ideation, n=62).

Paranoid and teleological thinking give rise to distinct social hallucinations in vision.

Paranoia (believing others intend harm) and excess teleological thinking (ascribing too much purpose) are non-consensual beliefs about agents. Human vision rapidly detects agents and their intentions. Might paranoia and teleology have roots in visual perception? Using displays that evoke the impression that one disc ('wolf') is chasing another ('sheep'), we find that paranoia and teleology involve perceiving chasing when there is none (studies 1 and 2) - errors we characterize as social hallucinations.

Differing Pattern of Mismatch Negativity Responses in Clinical and Nonclinical Voice Hearers Challenge Predictive Coding Accounts of Psychosis.

Background: Among people with schizophrenia (PSZ), reduced mismatch negativity (MMN) is conceptualized as evidence of disrupted prediction error signaling that underlies positive symptoms. However, this conceptualization has been challenged by observations that MMN and positive symptoms are often uncorrelated. In the current study, we tested the hypothesis that reduced MMN is associated with the presence of hallucinations and delusions specifically rather than the presence of a psychiatric illness.