The effects of oxytocin on primates’ working memory depend on the emotional valence of contextual factors

Abstract

HighlightsHigher cognitive demands (longer delay intervals), adversely affected monkeys’ performance in working memory task.Monkeys’ accuracy and also the response speed decreased when they matched stimuli with positive or negative emotional content.Oxytocin enhanced the adverse effects of negative stimuli, however, moderated the effects of positive stimuli.Our study on monkeys does not support models suggesting general effect of oxytocin in enhancing salience or heightening of attention to social stimuli. ABSTRACT Current models suggest that neuropeptide oxytocin modulates the salience of emotional/social stimuli and consequently influences perceptual, attentional and learning processes that underlie social behaviour. Therefore, oxytocin has been considered as a potential treatment in managing social and communication deficits in neuropsychological disorders. Recent studies indicate that effects of oxytocin on social and cognitive functions greatly vary and even lead to opposite outcomes. The factors leading to such variabilities in behavioural effects of oxytocin and their underlying mechanisms remain unclear. Here, we examined the effects of exogenously administered (intranasal) oxytocin (48 IU) on cognitive functions of macaque monkeys within a controlled experimental condition in a randomized crossover study. Monkeys performed a working memory task in which they memorized and subsequently matched stimuli with different emotional/social content (positive, negative, and neutral) at different levels of cognitive difficulties (delay period). Monkeys’ accuracy was lower at longer delay intervals indicating that higher cognitive demands adversely affected their performance. There was a significant difference in accuracy and response time between the three emotional conditions. The effects of oxytocin on monkeys’ performance were dependent on the emotional content of stimuli so that oxytocin enhanced the adverse effects of negative stimuli, however, moderated the effects of positive stimuli. Our findings in monkeys do not support models suggesting a general effect of oxytocin in enhancing salience or heightening of attention to social stimuli and instead suggest that the cognitive effects of oxytocin depend on the emotional valence of contextual factors.