Investigating the neural network correlates of apathy, disinhibition, and executive dysfunction in active-duty United States Special Operations Forces

Abstract

United States Special Operations Forces (SOF) experience neurobehavioral symptoms that can adversely affect training and combat operations. Understanding the neurobiological basis for these symptoms may guide prevention and treatment. In 29 male active-duty SOF with mean (SD) 17(4) years of service, we tested whether self-reported symptoms of apathy, disinhibition, and executive dysfunction measured by the Frontal Systems Behavior Scale, were related to functional magnetic resonance imaging and positron emission tomography biomarkers (translocator protein and tau) of the limbic, salience, and executive control networks. Higher disinhibition was associated with lower functional connectivity and higher tau signal within the salience network, though both associations diminished with age. These findings provide the basis for future multimodal studies to elucidate the relationship between neurobehavioral symptoms and neuroimaging biomarkers in the context of repeated blast exposure.

Keywords: Blast injuries; Functional magnetic resonance imaging; Military personnel; Neurobehavioral symptoms; Positron emission tomography.