What determines sexual behavior? Also, to what extent are immune cells and learned factors related?
When it comes to sexual behavior, are we usually ‘committed’ to acting like men or women? Do biological factors determine our social behavior? How much of this is learned behavior? Indeed, according to a recent study, immune cells (mast cells) affect our sexual behavior.
The study observed changes in a number of immune cells that shaped sexual behavior. The focus of the study was on how mast cells, a certain type of immune cell, affected our sexual behavior. Do they actually make us be more masculine or ‘feminine’?
The study found that immune cells, often ignored as variables, play an important role in determining whether an animal’s sexual behavior will be more typical for a man or a woman. In addition, researchers at Ohio State University, where this study was conducted and published in The Journal of Neuroscience, have come up with a surprising new explanation for how young brains are shaped by future sexual behaviors.
Are we ‘committed’ to certain sexual behaviors?
For many years, researchers have provided evidence that it is difficult to classify sexual behavior when it comes to people. In fact, it is difficult to label some kind of behavior as ‘male’ or ‘female’. In addition, many recent studies suggest that the subtle characteristics of our body without our knowledge can affect our behavior.
The new research examines the role that a particular type of immune cell (mast cell) plays in the development of sexual behavior. The researchers conducted their study on mice. They analyzed men with inactive mast cells and women with active mast cells. They also looked at the preoptic region of the brain in the hypothalamus. This contributes to the regulation of sexual behaviors.
Kathryn Lenz is an assistant professor of psychology and neuroscience at Ohio State University and director of the study. “The hypothalamus is the most sexually dynamic region of the brain. In addition, it is very important for social behaviors such as male-type reproduction and provoking maternal behavior in females”.
The importance of estrogen in sexual characteristics
The team observed the behavior of male rats with inactive mast cells when exposed to mating-ready females. Compared to control male rats, they showed a lower degree of interest in mating. Conversely, female rats with active mast cells exhibited sexual behavior, usually specific to male rats.
Lenz explains that it is fascinating to watch this, as ‘male’ females do not have the ‘equipment’ to engage in male reproductive behavior. However, this was not understood from his actions. In fact, Lenz noted, “rats appear to be strongly motivated to try to engage in male sexual behavior with other females.”
The researchers found that estrogen activates mast cells in the brain and that mast cells drive the sexual development of the animal. Indeed, estrogen plays an important role in the development of male traits.
Scientists know that hormones program gender differences during early development. However, they have limited knowledge of changes in the cellular level that contribute to the brain and behavior.
Researchers suggest we need to learn more about behavioral development. In particular, learning how changes occur at the cellular level while the fetus is still in the womb.
Some events during pregnancy may be a possible factor. These events can affect the biological structure of the fetus and behavioral tendencies. For example, allergic reactions that trigger inflammation or different types of injuries.
“Although these mast cells in the brain are relatively small, they seem crucial to lifelong brain development, and this should really open our eyes to the potential role of different immune cells in the human brain,” Lenz explains. “There’s a lot we don’t know, and we need to be careful with all the cells in the brain and how they talk to each other,” he concludes.
