催产素 z-bo 2020-11-03 395

　　Like many newborn mammals, young mice will use crying to attract mother mice's attention. However, a mother mouse is not born to recognize such shouts. She must learn to recognize the voices of offspring—just as a parent learns to recognize the cry of a baby. At present, a research team has discovered that oxytocin, a hormone related to trust and mother-child relationship, is the key to this learning process. Only when oxytocin acts on the brains of the mother mice, she will return the maternal worry and care to the young mice calling for help.

　　"This is definitely a meaningful study...especially for diseases such as autism." said Larry Young, a neurobiologist at Emory University in Atlanta (he was not involved in the study).

　　In order to understand the effect of oxytocin on the brain of mother mice, scientists at the New York University School of Medicine first studied the response of mother mice to pups calling for help under normal circumstances. Young rats will use ultrasound to call for help when they leave the nest. This happens from time to time when mother rats bring them to a new environment (to avoid predators, mother rats often move). When the mother rat hears such calls, she will run to the lost pups, pick them up and take them back to the nest. Other scientists have confirmed that even if the pups are not biological, the female mice will respond to the call for help, and they will always run to the source of the call for help. However, most of the unmated female rats appear "very unfeeling" and seem indifferent to the pups' cry for help. However, if an unmated female mouse is raised with other mothers and children, or injected with oxytocin, she will respond to the mouse's cry for help.

　　This discovery made the leader of the research team, neurobiologist Robert Froemke, suspect that oxytocin must help "transform the brains of unmated female mice into the brains of mothers." But how is this done? The researchers learned from other studies that the auditory cortex, which controls sound processing in the mother mouse’s brain, stores memories of crying for help from young rats. The auditory cortex is divided into left and right sides. The research team found oxytocin receptors on both sides. And the neurons that synthesize oxytocin-this is an unprecedented discovery. They also found that the left auditory cortex has extremely rich oxytocin receptors, suggesting that this part of the brain is specifically responsible for recognizing social signals. "This is very similar to the speech processing process of human brain lateralization," Froemke said. For most people, the structure of the left hemisphere is used to control language.

　　Scientists used drugs to inhibit the activity of the left auditory cortex and confirmed the importance of this area in the rescue behavior of female mice: The female mice treated with drugs obviously ignored the young mice calling for help.

　　According to the online report of the research team in Nature, when oxytocin was injected into the left auditory cortex of unmated female mice, oxytocin significantly increased the response speed of female mice searching for pups when compared with saline injection. For some female mice injected with oxytocin, the effect was "almost immediate," Froemke said. "They didn't have any rescue behavior before, and then--suddenly, they were like motherhood overflowing!"

　　Based on other experiments conducted by the researchers, they found that oxytocin helps mother mice learn and build memories of pups calling for help, and drives them to take care of pups. Young said, "Oxytocin not only ensures that the female mouse brain pays attention to these social signals, but it also changes their behavior."

　　Robert Liu, a neurobiologist at Emory University, said the discovery of a new mechanism for oxytocin is a breakthrough. "We didn't expect that oxytocin might play a role in the brain, but this is the current surprise (in this field)." He and other researchers believe that oxytocin may also be involved in the olfactory bulb and vision. Signal processing. And, if this is the case, this substance called "love hormone" is expected to improve the treatment of diseases such as autism or postpartum depression in time.