Oxytocin increases brain activity of mothers

New research finds that mothers of 1-year-old infants have stronger brain responses to human faces after nasal spray administration of oxytocin.

The findings contribute to understanding the hormone's effect on parent-infant interaction

New research finds that mothers of 1-year-old infants have stronger brain responses to human faces after nasal spray administration of oxytocin.

A study from Tampere University in Finland has found that the hormone oxytocin triggers strong brain responses to infant and adult facial pictures in mothers of 1-year-old infants when administered via nasal spray. Oxytocin is also a neuropeptide with a key role in labor induction, lactation, and mammal maternal bonding.

In recent years, studies on oxytocin’s influence on facial perception, emotions, and the processing of social information have been implemented with the nasal administration of the hormone. Among the findings achieved with nasal spray applications, scientists have discovered how the hormone raises brain activity and emotion recognition in facial perception and furthermore, studies are hinting at a key role for the hormone in the processing of social information and the construction of social bonds. But although there have been many studies on intranasal oxytocin effects, few have dealt directly with its effects on the mothers of young children.

The researchers at Tampere University wanted to determine if nasal spray oxytocin affected the neural responses to faces in 1-year-old-infants’ mothers. The study aimed to find if these effects were more accentuated in response to infant's faces, as the hormone is known to influence early caregiving behaviors. This was achieved by measuring information gathered in the initial stages of visual perception that can be collected through electroencephalography (EEG).

52 women, all mothers of 1-year-old infants, took part in the experiment comprised of two rounds of laboratory visits. For each visit, the mothers were given a placebo or the oxytocin nasal spray before each EEG measurement through a double-blind allocation of doses, as neither the mothers or researchers knew which spray was placebo or dosed.

The observations showed that N170 (a component of the EEG signal) raised when the female individuals were shown infant and adult faces and this effect was much stronger after the administration of oxytocin. However, the observations could not indicate a clear distinction if whether oxytocin effects were larger in response to infant or adult faces.

Tampere University research fellow Mikko Peltola, associated with the study, considered that this study was important because oxytocin-impact research has rarely included the mothers of infants. Hopefully, more extensive research can gather more evidence to look into how oxytocin influences maternal sensitivity to infant signals. In the months ahead, research like this will help find new aspects affecting early parent-infant interaction.

Peltola MJ, Strathearn L, & Puura K. (2018). Oxytocin promotes face-sensitive neural responses to infant and adult faces in mothers. Psychoneuroendocrinology. https://doi.org/10.1016/j.psyneuen.2018.02.012