Altered Insular Function during Aberrant Salience Processing in Relation to the Severity of Psychotic Symptoms

Abstract

There is strong evidence for abnormal salience processing in patients with psychotic experiences. In particular, there are indications that the degree of aberrant salience processing increases with the severity of positive symptoms. The aim of the present study was to elucidate this relationship by means of brain imaging. Functional magnetic resonance imaging was acquired to assess hemodynamic responses during the Salience Attribution Test, a paradigm for reaction time that measures aberrant salience to irrelevant stimulus features. We included 42 patients who were diagnosed as having a psychotic disorder and divided them into two groups according to the severity of their positive symptoms. Whole brain analysis was performed using Statistical Parametric Mapping. We found no significant behavioral differences with respect to task performance. Patients with more positive symptoms showed increased hemodynamic responses in the left insula corresponding to aberrant salience than in patients with less positive symptoms. In addition, left insula activation correlated negatively with cumulative antipsychotic medication. Aberrant salience processing in the insula may be increased in psychosis, depending on the severity of positive symptoms. This study indicates that clinically similar psychosis manifestations share the same functional characteristics. In addition, our results suggest that antipsychotic medication can modulate insular function.

Deficits in context-dependent adaptive coding in early psychosis and healthy individuals with schizotypal personality traits

“…At a more general level, the impaired neural reward adaptation in the striatum and insula is in line with a general deficit in basic information processing and with studies showing aberrant salience processing in individuals at risk for psychosis and early disease stages (Manoliu et al, 2014;Smieskova et al, 2015;Walter et al, 2016;Winton-Brown et al, 2017). Specifically, the imprecise neural representation of reward information could lead to increased uncertainty about external stimuli or internal values.…”

Combined Parietal-Insular-Striatal Cortex Stroke with New-Onset Hallucinations: Supporting the Salience Network Model of Schizophrenia

“…The salience network (insular cortex, parietal cortex, and striatum), shown in Figure 3, has been implicated in a function known as the salience monitoring and processing. Salience is defined as the effectiveness of a stimulus to stand out from its neighbors [7]. A stimulus might be considered to be salient by feature contrast, novelty, emotional, or motivational association.…”

“…Furthermore, decreased connectivity within neural systems involved in emotion processing and hyperconnectivity between the emotion system (AN) and the salience processing system (VAN) may relate to the deficits in emotion perception and regulation. Circles refer to reduced connectivity within the corresponding networks [7].…”

“…Another circuit of abnormal connection identified is the salience network (SN) consisting of the insular cortex, parietal anterior cingulate cortex, and striatum, as well as limbic structures [7]. While the posterior insula plays a key role in integrating sensory and motor information to mediate behavioral responses to interoceptive and external cues, the anterior portion of the insula functions to integrate this sensory and interoceptive feedback from the posterior insula with cognitive and emotional responses to the same stimuli, to create a conscious evaluation of affective experience.…”

Altered Spontaneous Brain Activity in Somatic Symptom Disorder: A Resting-state fMRI Study

“…The DMN deactivates during conscious attentional shift to environmental-related stimuli, re ecting introspective, self-relevant processes and affective decisions [28,29]. The SN consists of the insular cortex, parietal ACC, striatum, and limbic structures [30,31], which may be a transitional network that links cognition and emotion/interoception [32]. Previous neuroimaging studies indicated that DMN and SN activity are related to self-relevant processes and attention to internal and external stimuli, including nociceptive input [33][34][35].…”