A new study in rodents shows that two groups of nerve cells can act as “on-off switches” for males to mate and attack. These neurons seem to send signals between the two parts of the brain (the amygdala and the posterior or posterior part of the hypothalamus) to jointly regulate emotions including fear, anxiety, and aggression.
Led by researchers at New York University’s Grossman School of Medicine, this study showed that male mice had difficulty in intercourse during the experiment, which prevented a group of amygdala cells from communicating with the hypothalamus (MPN signaling cells). signal. On the contrary, when the same signal is enhanced, these animals are not only able to mate, but also repeatedly courting females that are unacceptable to females, which they usually cannot do.
Similarly, when the second cell population (VMHvl signaling cells) in the amygdala that also communicates with the hypothalamus is blocked, rodents attack unfamiliar males at half the frequency of the latter. When these same neurons are triggered, the mouse becomes abnormally aggressive, even attacking its female companions and familiar males.
Shan Gaolong, a postdoctoral researcher at New York University’s Langen School of Health and its Institute of Neuroscience, said: “Our findings provide new insights into the key role of the posterior amygdala in driving male sexual behaviors such as sexuality and aggressiveness.”
Past studies have shown the role of the amygdala in regulating social behavior, but until now, experts have not discovered its exact role in sexual behavior. Instead, the researchers focused on the hypothalamus, where both MPN and VMHvl structures are located, as a regulator of brain mating and fighting.
The new survey will be published online in the magazine on July 27 Natural NeuroscienceDr. Yamaguchi said that it was the first tissue to discover two different sets of cells that facilitate communication between the posterior amygdala and the responsible and aggressive part of the hypothalamus. He added that this also provides key evidence that the posterior part of the amygdala has a “huge” effect on social behavior.
In this study, the researchers observed the brain cell activity of more than 100 male mice that were mounted and fighting. The authors measured the frequency with which nerve cells naturally emit signals in animals throughout the day. They found that MPN signaling cells are most active during sex, while VMHvl signaling cells are most active when confronted with other males. Then, for each of these two cell groups, the researchers inhibited or activated neurons and observed how often the mice tried to partner with their partners or attack strange males placed in their enclosures.
Dr. Dayu Lin, associate professor and senior researcher at New York University Langen and its Institute of Neuroscience, said: “Our new understanding of which cells trigger sexual and aggressive behaviors will help us choose when designing future psychiatric treatments. A better brain target.”
Lin still warns that much of the structure of the amygdala is still poorly understood, and researchers still need to determine how these findings translate into the human brain. Her team also plans to study the interaction of two sets of nerve cells in the brains of female rodents.
The research was funded by R01MH101377, R21MH105774, R01HD092596 and U19NS107616 from the National Institutes of Health.
In addition to Yamaguchi and Lin, the other NYU Langone researchers involved in this study are Dr. Wei Dongyu; Soomin Song, Ph.D; and Dr. Nicolas Tritsch. Dr. Byungkook Lim of the University of California, San Diego provided support from other researchers.
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