Introduction The brainʼs oxytocin system is involved in a variety of addictive behaviors. In animal
studies, the application of oxytocin led to a permanent decrease in the preference
for alcoholic beverages and to a reduction in alcohol consumption. The effects of
oxytocin have been linked to the modulation of neurotransmission and functional connectivity
in the brainʼs reward system, the striatum and the nucleus accumbens (NAc). First
human studies were able to demonstrate an effect of oxytocin on subjective alcohol
cravings and neural cue-reactivity. However, the effects of oxytocin on functional
connectivity during the presentation of alcohol-related stimuli have not been investigated
in human studies.
Methods We investigated the effects of oxytocin on functional brain activation in a randomized
cross-over trial in N = 15 participants with high alcohol consumption using functional
magnetic resonance imaging (fMRI). 24 IU oxytocin vs. placebo (intranasal) were applied
40 minutes prior to the assessment of functional brain connectivity during the presentation
of alcohol and neutral stimuli.
Results The fMRI results show a significant modulation of functional connectivity in the
NAc, thalamus, and paracingular gyrus by oxytocin during the presentation of alcohol-related
stimuli (all pFDR < 0.05). This effect was specific to the alcohol condition and was not seen during
the presentation of neutral images. The results also indicated a significant correlation
between NAc-connectivity and subjective desire for alcohol (r = 0.538, p = 0.024).
Conclusion The results of the current study provide first evidence of a condition-specific and
significant attenuation of NAc-connectivity by oxytocin, which was associated with
a lower subjective alcohol craving. The oxytocin-induced modulation of NAc-connectivity
was specific for the processing of alcohol stimuli and could reflect a reduction in
the stimulus salience of alcohol stimuli by oxytocin.