Oxytocin, produced by the hypothalamus and secreted by the pituitary gland, induces contractions of the uterine muscle during labor and stimulates milk secretion. But other and eventual functions - or applications - of the hormone have been the subject of several studies.
Now new research highlights its role in face recognition. The work, published in this Wednesday's edition (7/1/2009) of the The Journal of Neuroscience (www.jneurosci.org), points out that oxytocin is able to increase an individual's ability to distinguish between countenance.
According to the authors, study participants who received a dose of oxytocin by nasal spray showed improved facial recognition, but not inanimate objects.
“Recognizing a familiar face is a key component to the success of social interaction between humans. Our study indicated that oxytocin in humans immediately strengthened the ability to correctly recognize and discriminate faces, ”said Peter Klaver of the University of Zurich, one of the study's authors.
Previous research with mice has found that the hormone plays an important role in distinguishing which other animal is familiar. But unlike humans, who rely on sight for recognition, mice use their sense of smell.
Participants were divided into two groups. The first received applications containing oxytocin, and the second, placebo. The researchers then displayed images of faces and objects, such as houses, sculptures or landscapes.
The next day, the volunteers underwent a surprise test. Shown were images seen the day before and new ones. Participants had to classify the scenes as new, which were among those presented the day before or familiar - which they could distinguish, but without recalling the context.
The volunteers who used the oxytocin spray were able to perceive previously displayed faces more efficiently than the others.
However, both groups had the same advantage regarding object images.
According to the researchers, the result, in addition to the role of oxytocin, indicates the existence of different mechanisms for social and non-social memory.
“The study showed that a single dose of oxytocin is sufficient to increase recognition memory for social stimuli. The results point to an immediate and selective effect of the hormone:
strengthening the neuronal systems involved in social memory, ”said Ernst Fehr of the University of Zurich, Switzerland, in a comment on the study released by the United States-based Society for Neuroscience.
"The study has important applications in problems such as autism where social information processing is impaired," said Larry Young of Emory University, another researcher studying the effects of oxytocin.
Adapted from: Agência Fapesp - Scientific Dissemination (7/1/2009)