Abstract
Impairments in the attribution of salience are thought to be fundamental to the development of psychotic symptoms and the onset of psychotic disorders. The aim of the present study was to explore longitudinal alterations in salience processing in ultra-high-risk subjects for psychosis. A total of 23 ultra-high-risk subjects and 13 healthy controls underwent functional magnetic resonance imaging at two time points (mean interval of 17 months) while performing the Salience Attribution Test to assess neural responses to task-relevant (adaptive salience) and task-irrelevant (aberrant salience) stimulus features. At presentation, high-risk subjects were less likely than controls to attribute salience to relevant features, and more likely to attribute salience to irrelevant stimulus features. These behavioural differences were no longer evident at follow-up. When attributing salience to relevant cue features, ultra-high-risk subjects showed less activation than controls in the ventral striatum at both baseline and follow-up. Within the high-risk sample, amelioration of abnormal beliefs over the follow-up period was correlated with an increase in right ventral striatum activation during the attribution of salience to relevant cue features. These findings confirm that salience processing is perturbed in ultra-high-risk subjects for psychosis, that this is linked to alterations in ventral striatum function, and that clinical outcomes are related to longitudinal changes in ventral striatum function during salience processing.
Highlights
According to the aberrant salience model of psychosis (Heinz, 2002; Kapur, 2003; Howes & Murray, 2014), psychotic symptoms develop as a result of the inappropriate assignment of salience to contextually irrelevant internal and external experiences
Our objective was to assess the relationship between changes in clinical features in a ultra-high risk (UHR) cohort and longitudinal changes in VS activation elicited during the Salience Attribution Test (SAT) paradigm
The two groups did not differ in age, gender, handedness, intelligence quotient or cigarette, alcohol, cannabis and cocaine consumption, but healthy controls (HCs) had more years of education
Summary
According to the aberrant salience model of psychosis (Heinz, 2002; Kapur, 2003; Howes & Murray, 2014), psychotic symptoms develop as a result of the inappropriate assignment of salience to contextually irrelevant internal and external experiences. This model is supported by evidence that patients with schizophrenia respond faster to task-irrelevant stimulus features than healthy controls (HCs) (Pankow et al 2016), and that patients with prominent delusions rate irrelevant stimuli as more potentially rewarding than patients without delusions (Roiser et al 2009). The aim of the present study was to explore longitudinal alterations in salience processing in ultra-high-risk subjects for psychosis
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