Oxytocin effects on self-referential processing: behavioral and neuroimaging evidence.

Oxytocin (OT) influences other-oriented mental processes (e.g. trust and empathy) and the underlying neural substrates. However, whether and how OT modulates self-oriented processes and the underlying brain activity remains unclear. Using a double-blind, placebo-controlled between-subjects design, we manipulated memory encoding and retrieval of trait adjectives related to the self, a friend and a celebrity in a self-referential task in male adults. Experiment 1 (N = 51) found that OT vs placebo treatments reduced response times during encoding self-related trait adjectives but increased recognition scores of self-related information during memory retrieval. Experiment 2 (N = 50) showed similar OT effects on response times during encoding self-related trait adjectives. Moreover, functional magnetic resonance imaging (fMRI) results revealed that OT vs placebo treatments decreased the activity in the medial prefrontal cortex (MPFC) involved in encoding of self-related trait adjectives and weakened the coupling between the MPFC activity and a cultural trait (i.e. interdependence). Experiment 3 (N = 52) revealed that OT vs placebo treatments increased the right superior frontal activity during memory retrieval of self-related information. The results provide behavioral and fMRI evidence for OT effects on self-referential processing and suggest distinct patterns of OT modulations of brain activities engaged in encoding and retrieval of self-related information.