Another difference between male and female brains
Scientists have explained the different effects of oxytocin on men and women
Three-dimensional model of the oxytocin molecule (MindZiper / Wikimedia Commons)
Scientists from China and Germany have found out that the neurotransmitter oxytocin has different effects on the amygdala in the brain in men and women. As a result, women form a positive impression of strangers, while men, on the contrary, have a negative one. The study is published in the Proceedings of the Natural Academy of Sciences (Gao et al., Oxytocin, the peptide that bonds the sexes also divides them).
The amygdala, or amygdala, is an area of the brain that has the shape of an almond and is located inside the temporal lobe in each hemisphere. Amygdala plays a key role in controlling friendly and "avoidant" behavior, which changes under the influence of oxytocin. It was previously known that the amygdala in men and women is activated to varying degrees in response to positive and negative social information, such as "scary" faces or threatening events.
The neurotransmitter and hormone oxytocin is produced in mammals and plays a key role during childbirth and lactation. It forms a feeling of attachment of the mother to the child immediately after childbirth. Oxytocin also affects the improvement of social interaction between people, the emergence of a more friendly relationship between partners in a couple. However, recent studies have revealed different effects of oxytocin on the behavior of men and women. Women under the influence of oxytocin become more friendly and altruistic, while men begin to avoid people, become more selfish and see others as competitors.
If a person meets a stranger whom someone characterizes positively, then the newcomer is perceived as a nice and friendly person, and vice versa, if a new person is accompanied by negative characteristics, then most likely he will be avoided. The authors of the work decided to find out whether oxytocin will affect the behavior of men and women differently, whether they will perceive strangers differently.
The researchers designed an experiment in which participants were shown photos of people with a neutral facial expression, which were accompanied by positive, negative or mixed descriptions. The researchers hypothesized that oxytocin would alter the amygdala's "response" and its interaction with other parts of the brain depending on the gender of the participant. In women, the perception of positive social traits will increase, and in men, on the contrary, negative ones.
The experiment involved 74 volunteers (37 men, 37 women) aged 19-27 years. The participants of the experiment were instilled either an oxytocin solution or a placebo into their nose. 45 minutes after the procedure, they underwent functional magnetic resonance imaging, during which the subjects were shown photos of people with a neutral facial expression. The images were accompanied by characteristics: "praises other people / objects", "criticizes other people / objects". Then the participants of the experiment were asked to evaluate the attractiveness of the person in the photo and his ability to win others over. At the same time, scientists observed the activity of the amygdala of the subjects.
The sequence of showing photos during the experiment
(here and below are the pictures from the PNAS article)
It turned out that oxytocin reversed the picture of the amygdala reaction to the photo in men and women. In the case of placebo, the reaction to negative descriptions was stronger in women and weaker in men than to positive ones. Under the influence of oxytocin, the reaction changed: women began to react more strongly to positive descriptions, and men began to perceive criticism more strongly. In other words, oxytocin made women treat strangers more confidentially, and men, on the contrary, made them more wary.
A. Activation of the left amygdala under the influence of oxytocin. L is the left hemisphere, R is the right hemisphere.
B. Activation of the amygdala under the action of oxytocin (colored columns) and placebo (white columns) in women and men.
On the Y axis: the difference in activation when showing "critical" (CP) and "laudatory" inscriptions (PP). CP > PP
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24.06.2016