Background

Hedonic functioning can vary on a state and trait level from highly hedonic to the loss of almost all pleasure and interest, i.e. the symptom of anhedonia. Research indicates that a dysfunction of any component of the reward process, for instance reward anticipation, consummation, or reward learning, could lead to subjectively reported anhedonia und impede hedonic well-being. 

Aims

During fMRI, consummatory pleasure is often assessed using monetary rewards. Here, we aim to examine the neural correlates of hedonic functioning during pleasant touch. 

Method

Seventy young healthy adults (aged 18-30), varying in trait hedonic functioning from anhedonic to highly hedonic completed an established affective touch paradigm during fMRI. After each of the 36 trials of visuo-tactile stimulation, participants subjectively rated the pleasantness of their experience. Hedonic functioning levels were assessed with established trait and state pleasure scales. We analyzed the neural activation related to positive and negative valence with two parametric modulators based on the individual subjective ratings. The positive valence modulator was selected to assess correlations with state and trait pleasure scales.

Results

Trait and state pleasure scores significantly correlated with the pleasure ratings during the visuo-tactile affective touch paradigm. On a whole-brain corrected level (p_FWE < .05), we found significant peak activations related to state but not trait hedonic functioning in the ventro-medial prefrontal cortex (vmPFC) and the right inferior parietal lobe (IPL) area PFt.

Conclusion

Our results indicate that in participants with lower levels of state hedonic functioning activation in the vmPFC is more strongly tied to the subjective ratings of each trial, while activation in the IPL follows the subjective ratings of pleasure to a lesser extent. Thus, a complex picture of neural correlates of hedonic functioning during pleasant touch arises.