What do you feel? Adolescent drug and alcohol users show altered brain response to pleasant interoceptive stimuli.
BACKGROUND
Altered interoception, i.e., processing of stimuli from inside the body, has been considered an important component of drug-taking behavior. However, approaches to examine interoceptive sensitivity in humans have been limited. This study examined the hypothesis that adolescents with substance use disorder show altered interoceptive processing, measured by stimulating mechano-receptive C-fibers (MR-CF) via soft touch.


METHODS
Adolescents with substance use disorders (SUD, n=15) and comparison youth (CON, n=17) underwent functional magnetic resonance imaging (fMRI) during anticipation or reception of a positively valenced "Soft Touch" consisting of MR-CF stimulation to the palm or forearm. Visual analog scales (VAS) indexed subjective interoceptive experience (e.g., pleasantness, intensity).


RESULTS
Across all conditions, SUD displayed attenuated left posterior insula activation compared to CON. Greater left anterior insula and right lentiform nucleus activation was evident during the application of soft touch for SUD but not for CON. Whereas for CON, greater left anterior insula activation was associated with higher pleasantness ratings, pleasantness was linked to less anterior insula activation in SUD. Finally, within SUD, attenuated posterior insula activation was related to more recent cannabis use.


CONCLUSIONS
SUD adolescents exhibit blunted somatovisceral processing of pleasant stimulation, heightened sensitivity in regions responsible for processing reward value, and altered relationships between interoceptive processing and subjective experience.
San Diego State University/University of California San Diego, Joint Doctoral Program in Clinical Psychology, 6363 Alvarado Court, Suite 103, San Diego, CA, USA. Electronic address: ramiglio@ucsd.edu.
Robyn
R
Migliorini
Jennifer L
JL
Stewart
April C
AC
May
Susan F
SF
Tapert
Martin P
MP
Paulus
D000293:Adolescent; D000437:Alcoholism / Q000523:psychology*; D001519:Behavior / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology*; D017072:Neostriatum / Q000502:physiology; D010812:Physical Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D014110:Touch / Q000502:physiology
Alcohol; Cannabis; Interoception; Reward; fMRI