Oxytocin (OT) exerts widely modulatory effects on socio-emotional functions in humans, which can be achieved via enhancing the salience of social cues by interacting with the dopaminergic attention system. However, there is a lack of direct evidence for OT modulating attentional processing, with its underlying neural mechanisms remaining to be elucidated.

In a double-blind, placebo-controlled, between-subject design, 60 healthy male participants were recruited. We combined pharmaco-electroencephalography with two modified tasks (a cue-target visual search [CTVS] task and a face distractor interference [FDI] task) to investigate whether intranasal OT can modulate attentional processing of social cues in top-down versus bottom-up task sets.

In the CTVS task, OT accelerated participants’ response time to target faces, which was paralleled by a larger N170 and stronger theta power, suggesting that OT promoted early top-down attentional processing of social cues. In the FDI task, OT inhibited the distractive effect of task-irrelevant emotional faces in the first half of the task via facilitating top-down attentional control to targets as reflected by enhanced attentional selection (increased N2pc) and more efficient attentional processing (decreased P300). However, in the second half, OT switched from facilitating top-down attentional control to potentiating bottom-up attentional capture by emotional face distractors, as evidenced by OT reducing response accuracy but having no effects on the N2pc and P300.

Our findings not only provide evidence for the role of OT in modulating attentional processing of social cues but also lend support to its therapeutic potential in normalizing such attentional deficits.