Aberrant Salience, Information Processing, and Dopaminergic Signaling in People at Clinical High Risk for Psychosis

Abstract

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The effects of developmental trauma on reinforcement learning and its relationship to psychotic experiences: a behavioural study

“…Our finding that deficits in RL may, in part, mediate increased psychotic experiences in individuals exposed to developmental trauma indicates that these impairments may serve as markers of latent vulnerability to psychosis. This is in line with predictive coding accounts of psychosis whereby aberrant RL contributes to inflexible belief updating through an uncorrected discrepancy between priors and perceptual information, leading to the development of hallucinations and maintenance of delusional beliefs [11,13,16,55].…”

“…The dopaminergic system is thought to play a central role in both HPC [11,18,56,57] and the pathogenesis of psychosis [58,59]. In accordance with traumatogenic neurodevelopmental and stress-diathesis models of psychosis [47,60,61], alterations to dopaminergic PE signalling, as a result of exposure to traumatic stressors, could compound the disjunction between priors and sensory information through impaired precision-weighting [56,57], making individuals with cumulative traumatic experiences increasingly prone to psychosis [48,55,62]. Indeed, dopaminergic function has been shown to be altered in survivors of developmental trauma [63,64,65] and animal models [66], and recent evidence suggests that developmental trauma may influence ventral striatal dopamine transmission to increase positive psychotic symptoms [67].…”

Neural Correlates of Aberrant Salience and Source Monitoring in Schizophrenia and at-Risk Mental States - A Systematic Review of fMRI Studies

“…delusions [24] and auditory hallucinations [25]. However, this model is still developed, with important questions yet to be answered [23]. On the behavioural level, one of the most prominently used markers of aberrant salience is a speeding of responses to irrelevant stimuli in undirected or probabilistic motivational tasks, like the Salience Attribution Test.…”

“…Griffin and Fletcher [42] presented an account joining source monitoring and predictive processing in a hierarchical model. In the predictive coding account of psychoses [23,25,43] aberrant salience is seen as a type of disruption in precision-weighing mechanisms. Proneness to strong prior beliefs (or underweighted prediction error [23]) about the experiences and expected shape of reality results in a top-down influence that takes precedence or outweighs perceptual input, resulting in false inferences.…”

Hippocampal disinhibition reduces contextual and elemental fear conditioning while sparing the acquisition of latent inhibition

“…LI refers to the reduced conditioning to a conditioned stimulus (CS), to which participants had been pre-exposed without consequence, and LI deficits have been reported in acute schizophrenia (Baruch et al, 1988; Gray et al, 1995; Rascle et al, 2001). One interpretation of reduced LI is that this reflects aberrant salience allocation to a stimulus that healthy participants had learned to ignore, and these findings contributed to the view that aberrant salience allocation is a key feature of schizophrenia and underlies psychotic symptoms (Gray et al, 1991; Howes et al, 2020; Kapur, 2003). Additionally, patients with schizophrenia show reduced aversive conditioning (Holt et al, 2009; Jensen et al, 2008; Romaniuk et al, 2010), which has been associated with negative symptoms (Holt et al, 2012).…”