Delusions and the Role of Beliefs in Perceptual Inference

Abstract

Delusions are unfounded yet tenacious beliefs and a symptom of psychotic disorder. Varying degrees of delusional ideation are also found in the healthy population. Here, we empirically validated a neurocognitive model that explains both the formation and the persistence of delusional beliefs in terms of altered perceptual inference. In a combined behavioral and functional neuroimaging study in healthy participants, we used ambiguous visual stimulation to probe the relationship between delusion-proneness and the effect of learned predictions on perception. Delusional ideation was associated with less perceptual stability, but a stronger belief-induced bias on perception, paralleled by enhanced functional connectivity between frontal areas that encoded beliefs and sensory areas that encoded perception. These findings suggest that weakened lower-level predictions that result in perceptual instability are implicated in the emergence of delusional beliefs. In contrast, stronger higher-level predictions that sculpt perception into conformity with beliefs might contribute to the tenacious persistence of delusional beliefs.

Perceptual suppression of predicted natural images

“…For example, one general prediction is that the future visual environment will be similar or identical to the current one (Weiss, Simoncelli, & Adelson, 2002; Wiskott & Sejnowski, 2002). Consistent with the Bayesian framework in this case, many studies have found that perceptual selection favors both repeated percepts (Leopold, Wilke, Maier, & Logothetis, 2002; Pearson & Brascamp, 2008; Pearson, Clifford, & Tong, 2008) and percepts associated with repeated context (Di Luca, Ernst, & Backus, 2010; Haijiang et al, 2006; Schmack et al, 2013; Sterzer et al, 2008). Perceptual selection also favors perceptual interpretations predicted by preceding stimulus motion (Attarha & Moore, 2015; Denison et al, 2011; Maloney et al, 2005).…”

Psychotic Experiences and Overhasty Inferences Are Related to Maladaptive Learning

“…In line with this, schizophrenia and/or psychotic symptoms have been consistently linked to the aberrant attribution of salience to stimuli ([34,35] for reviews). Similarly, schizophrenia and psychotic symptoms have been associated with a decreased influence of prior beliefs in perceptual inference ([36], see [37] for a review on visual illusions), although recent work suggests a complex interplay between prior beliefs and perceptual inference in psychosis-related conditions [38,39]. By the use of a feasible and interpretable model, our current study provides a formal description for the interaction between prior beliefs and new information, thereby elucidating the computational mechanisms underlying maladaptive learning and inference in psychosis.…”

Translational Perspectives for Computational Neuroimaging

“…Two separate fMRI and EEG studies examined potential mechanisms for this phenomenon: applying structurally analogous DCMs to fMRI and EEG data, these two studies consistently found a strengthening of bottom-up connections and diminished top-down connectivity in patients, consistent with the notion of reduced precision of predictions about facial stimuli (Dima et al, 2009(Dima et al, , 2010. Notably, weakening of top-down predictions may explain a range of perceptual alterations in schizophrenia (Notredame et al, 2014) and may also play a role in the initial formation of delusions (Schmack et al, 2013).…”