Current and former methamphetamine-dependent adults show attenuated brain response to pleasant interoceptive stimuli

Abstract

Aims: MD and AB individuals will show a diminished response to interoceptive stimuli. Methods: Recently abstinentMD (n=25), long-termAB (n=17), and comparison (CO, n=17) subjects completed a continuous performance taskduring functionalmagnetic resonance imagingwhile receiving a pleasant interoceptive stimulus. During anticipatory trials, a blue or yellow background signaled an impending slow brush stroke administered to the left palm or forearm, respectively, during upcoming interoceptive trials. Visual analog scales (VAS) indexed interoceptive experience (e.g. pleasantness, intensity). A linear mixed effects model was conducted with group as the between subjects variable, subject as a random factor, and condition (anticipationpalmand forearm, soft touchpalmand forearm) as the repeated factor. Correlations between significant brain results and VAS ratings were computed. Results: CO exhibited greater left posterior insula activation than MD and AB across trials. CO also showed greater activation than MD and AB in bilateral anterior cingulate and dorsal striatum during soft touch. Despite striatum attenuation during soft touch, AB rated the soft touch as more pleasant and less intense than MD and CO who did not differ. Conclusions: MD and AB exhibit attenuated interoceptive processing and decreased reward responsivity, findings that may relate to a reduced sensitivity to pleasant stimuli. Self-report and brain indices of reward may recover at different rates with long term abstinence from stimulants. Financial support: NIDA 5P20DA027843.