Discontinuing unhealthy behaviors, such as overeating or drug use, depends upon an individual‟s ability to overcome the influence of environmental reward cues. The strength of that influence, however, varies greatly depending upon the internal state of the body. Characterizing the relationship between interoceptive signaling and shifting drug cue valuation provides an opportunity for understanding the neural bases of how changing internal states alter reward processing more generally. Seventeen cigarette smokers rated the pleasantness of cigarette pictures when they were nicotine-sated or nicotine-abstinent. On both occasions, smokers also underwent fMRI scanning while performing a visceral interoceptive attention task and a resting-state functional connectivity scan. Hemodynamic, physiological, and behavioral parameters were compared between sated and abstinent scans. The relationships between changes in these parameters across scan sessions were also examined.
Smokers rated cigarette pictures as significantly more pleasant while nicotineabstinent than while nicotinesated. Comparing abstinent to sated scans, smokers also exhibited significantly decreased mid-insula, amygdala, and orbitofrontal activity while attending to interoceptive signals from the body. Change in interoceptive activity within the left mid-insula predicted the increase in smoker‟s pleasantness ratings of cigarette cues. This increase in pleasantness ratings was also correlated with an increase in resting-state functional connectivity between the mid-insula and the ventral striatum and ventral pallidum. These findings support a model wherein interoceptive processing in the mid-insula of withdrawal signals from the body potentiates the motivational salience of reward cues through the recruitment of hedonic „hotspots‟ within the brain‟s reward circuitry.
References
Avery, Jason A., Kaiping Burrows, Kara L. Kerr, Jerzy Bodurka, Sahib S. Khalsa, Martin P. Paulus, and W. K. Simmons. 2016. “How the Brain Wants What the Body Needs: The Neural Basis of Positive Alliesthesia.” Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology. doi:10.1038/npp.2016.128.