Neural correlates of the revised reinforcement sensitivity theory: A cross-sectional structural neuroimaging study in middle-aged adults.

The revised reinforcement sensitivity theory (RST) proposes that neurobiological systems control behavior: the fight-flight-freeze (FFFS) for avoidance of threat; behavioral approach/activation (BAS) for approach to rewards; and behavioral inhibition (BIS) for conflict resolution when avoidance and approach are possible. Neuroimaging studies have confirmed some theoretical associations between brain structures and the BAS and BIS; however, little representative population data are available for the FFFS. We investigated the neural correlates of the revised RST in a sample of 404 middle-aged adults (M age  = 47.18 (SD = 1.38); 54.5% female). Participants underwent structural magnetic resonance imaging and completed health questionnaires and the BIS/BAS/FFFS scales. We used multiple regression analyses to investigate the association between scale scores and volumes of a priori theoretically linked regions of interest while controlling for sex, age, intracranial volume, and cardio-metabolic variables; and conducted exploratory analyses on cortical thickness. The BIS was negatively associated with hippocampus laterality. At standard significance levels, the fear component of the FFFS was positively associated with anterior cingulate cortex; the BAS was positively associated with bilateral caudate; and the BIS was positively associated with posterior cingulate cortex volume. Furthermore, these neurobiological systems showed distinct patterns of association with cortical thickness though future work is needed. Our results showed that the neurobiological systems of the revised RST characterized in rodents can also be identified in the human brain.