Aberrant salience network functional connectivity in auditory verbal hallucinations: a first episode psychosis sample

Abstract

Auditory verbal hallucinations (AVH) often lead to distress and functional disability, and are frequently associated with psychotic illness. Previously both state and trait magnetic resonance imaging (MRI) studies of AVH have identified activity in brain regions involving auditory processing, language, memory and areas of default mode network (DMN) and salience network (SN). Current evidence is clouded by research mainly in participants on long-term medication, with chronic illness and by choice of seed regions made ‘a priori’. Thus, the aim of this study was to elucidate the intrinsic functional connectivity in patients presenting with first episode psychosis (FEP). Resting state functional MRI data were available from 18 FEP patients, 9 of whom also experienced AVH of sufficient duration in the scanner and had symptom capture functional MRI (sc fMRI), together with 18 healthy controls. Symptom capture results were used to accurately identify specific brain regions active during AVH; including the superior temporal cortex, insula, precuneus, posterior cingulate and parahippocampal complex. Using these as seed regions, patients with FEP and AVH showed increased resting sb-FC between parts of the SN and the DMN and between the SN and the cerebellum, but reduced sb-FC between the claustrum and the insula, compared to healthy controls.It is possible that aberrant activity within the DMN and SN complex may be directly linked to impaired salience appraisal of internal activity and AVH generation. Furthermore, decreased intrinsic functional connectivity between the claustrum and the insula may lead to compensatory over activity in parts of the auditory network including areas involved in DMN, auditory processing, language and memory, potentially related to the complex and individual content of AVH when they occur.

Common and distinct brain functional alterations in pharmacotherapy treatment-naïve female borderline personality disorder patients with and without auditory verbal hallucinations: a pilot study

“…In this study, we did not find a significant correlation between gFCD and the AVH severity in BPD-AVH patients. This observation was in agreement with previous findings that alterations in brain function were not correlated with the severity of clinical symptoms, for which it has been postulated that these brain alterations could be related to the trait of the symptoms rather than the "state" of symptoms [48][49][50][51][52][53][54][55].…”

Anterior Hippocampal–Cortical Functional Connectivity Distinguishes Antipsychotic Naïve First-Episode Psychosis Patients From Controls and May Predict Response to Second-Generation Antipsychotic Treatment

“…The question of how the anterior hippocampus functionally interacts with the salience network in FEP is of interest given aberrant salience monitoring is a core feature of psychosis, and the anterior hippocampus plays a key role in salience attribution: in humans, it activates in response to mismatch or novelty, 43,44 co-activates with the anterior insula during threat appraisal, 45 and has strong FC with subcortical nodes involved in salience processing 22,46,47 ; in rodents, the ventral hippocampus modulates salience according to context via interactions with the amygdala and prefrontal cortical areas. 45,48,49 Although the salience network and isolated nodes (dACC and insular cortex) have been previously reported to show altered within network FC (typically hypoconnectivity) relative to controls in UHR, 50,51 antipsychotic naïve FEP, 52,53 and chronic medicated schizophrenia patients, [54][55][56][57][58] few studies have assessed hippocampal FC with this network. Current findings suggest relative hypoconnectivity between the anterior hippocampus and cortical hubs in the salience network in unmedicated FEP patients.…”

Evidence in cortical folding patterns for prenatal predispositions to hallucinations in schizophrenia

“…Gyral and sulcal architecture is intrinsically related to the brain’s functional organization 14 . Functional neuroimaging studies have consistently reported alterations in the brain’s resting state networks in people who experience hallucinations, particularly in the salience network, which engages the anterior cingulate and anterior insula to determine the origin and salience of internal and external stimuli 15 , 16 . The salience network equally coordinates the transition between functional networks related to self- and task-processing, suggesting cross-network abnormalities in the manifestation of hallucinations 17 .…”