Intranasal Oxytocin's Dose-Dependent Effects on Amygdala and Reward System Explored in Men and Women

The neuropeptide oxytocin plays a crucial role in social bonding, trust, and emotional regulation, influencing brain regions like the amygdala (involved in emotion processing) and the reward system (mediating pleasure and motivation). While intranasal oxytocin is explored for conditions like autism spectrum disorder and social anxiety, its precise dose-response profile and potential sex-specific effects on these critical brain circuits remain poorly understood. Current therapeutic approaches often use fixed doses, potentially missing optimal effects or inducing unintended outcomes. Understanding how varying doses of oxytocin differentially impact neural responses in men versus women is essential for optimizing its clinical application and personalizing treatment strategies.

This study aimed to determine if intranasal oxytocin's effects on brain activation vary by dose and sex. Researchers administered different treatment doses of intranasal oxytocin or placebo to women and men. Participants underwent functional magnetic resonance imaging (fMRI) approximately 50 minutes after administration to assess brain activation. The primary endpoint was the blood-oxygen level dependent (BOLD) signal response in the amygdala and reward system to reward-related cues. Specifically, brain activation was measured while participants viewed images of their own versus unknown infant happy faces, a task designed to elicit social reward processing. The study design focused on comparing neural responses across different oxytocin doses and between sexes.

The abstract outlines the study's primary objective: to determine if intranasal oxytocin's impact on brain activation, specifically within the amygdala and the broader reward system, varies with the administered dose. Researchers aimed to assess these effects in both women and men, focusing on blood-oxygen level dependent (BOLD) signal changes during functional magnetic resonance imaging (fMRI). The study sought to identify whether different doses of oxytocin elicit distinct neural responses to reward-related cues, such as own versus unknown infant happy faces. They hypothesized that oxytocin would modulate neural processing of these social stimuli in a dose-dependent manner, and that these responses might differ between women and men. For instance, they would look for enhanced or diminished BOLD responses in areas associated with social cognition and reward processing. However, this abstract primarily describes the study's design and objectives, and does not present specific numerical findings, statistical results, or quantitative data regarding the observed dose-dependent effects or sex differences in brain activation.