Distinct Connectivity Signatures of Hallucinatory Experiences and Neuromelanin Signal in Community-Dwelling Adolescents.

Abstract

Few human imaging studies investigate psychotogenic models during late adolescence. The "triple network" model posits that hallucinations are related to abnormal connectivity among the frontoparietal (FPN), default mode (DMN) and salience/cingulo-opercular (CON) networks but has not been tested during this age range, and is not well integrated with the hyper-dopaminergic model of psychosis. We performed a cross-sectional analysis of 171 14-17 year-old community adolescents. Hallucinatory experience severity was measured using the Specific Psychotic Experiences Questionnaire. Resting-state functional connectivity was calculated among a priori DMN, FPN, and CON cortical regions. Long-term dopaminergic function was assessed using neuromelanin-sensitive MRI (NM-MRI) in the ventral tegmental area (VTA). We examined associations between hallucinatory experience severity, network-based connectivity, and VTA NM-MRI. Greater hallucinatory experience severity was associated with higher connectivity in a subnetwork composed of CON-DMN and CON-FPN edges, as well as with lower global system segregation. While VTA NM-MRI was not associated with hallucinatory experience severity, it negatively correlated with connectivity in the hallucination-related subnetwork and positively correlated with DMN connectivity among midline regions. Among 14-17-year-old community dwelling youth, abnormal triple network connectivity was associated with hallucination severity, replicating similar studies in psychotic adults. Long-term dopamine function and hallucination severity were associated with some similar aspects of the triple network. Pediatric studies of prodromal psychosis may benefit from tracking developmental trajectories of triple network connectivity, dopaminergic function, and hallucination-like phenomena.