AUTHOR=Strigo Irina A. , Spadoni Andrea D. , Simmons Alan N. 

TITLE=Understanding Pain and Trauma Symptoms in Veterans From Resting-State Connectivity: Unsupervised Modeling

JOURNAL=Frontiers in Pain Research

VOLUME=Volume 3 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/pain-research/articles/10.3389/fpain.2022.871961

DOI=10.3389/fpain.2022.871961

ISSN=2673-561X

ABSTRACT=Trauma and posttraumatic stress are highly co-morbid with chronic pain and are often antecedents to developing chronic pain conditions. Pain and trauma are associated with greater utilization of medical services, greater use of psychiatric medication and increased total cost of treatment. Despite high overlap in the clinic, the neural mechanisms of pain and trauma are often studied separately.  Here, resting state functional magnetic resonance imaging (rs-fMRI) scans were completed among a diagnostically heterogeneous sample of Veterans with a range of back pain and trauma symptoms. Using Group Iterative Multiple Estimation (GIMME), an effective functional connectivity analysis, we explored an unsupervised model deriving subgroups based on path similarity in a priori defined ROIs from brain regions implicated in the experience of pain and trauma. Three subgroups were identified by patterns in functional connection, and differed significantly on several psychological measures despite similar demographic and diagnostic characteristics. The first subgroup was highly connected overall, was characterized by functional connectivity from nucleus accumbens (NAc), anterior (ACC) and posterior cingulate (PCC) to the insula and scored low on pain and trauma symptoms. The second subgroup did not significantly differ from the first subgroup on pain and trauma measures but was characterized by functional connectivity from the ACC and NAc to thalamus and from ACC to PCC. The third subgroup was characterized by functional connectivity from thalamus and posterior cingulate (PCC) to nucleus accumbens (NAc) and scored high on pain and trauma symptoms. Our results suggest that despite demographic and diagnostic similarities, there may be neurobiologically dissociable biotypes with different mechanisms for managing pain and trauma. These findings may have implications for the determination of appropriate biotype-specific interventions that target these neurological systems.