Hormones shape love and lust differently in male and female brains

Summary: New research discovers how a cerebral circuit tune in hormonally in mice governs specific sexual mating behaviors. Scientists identified a subset of neurons in the prefrontal cortex that integrate oxytocin, ovarian hormones and social signals to modulate sexual receptivity in women and suppress the mating interest in men.

The activation of these neurons caused non -fertile females to be receptive, while silencing them during the Stan stopped their interest, with opposite effects on men. The findings show how identical brain circuits can produce dramatically different behaviors in men and females depending on hormonal states.

Key facts:

Hormone sensitive circuit: CACNA1H+ neurons in partner prefrontal bark control behaviors integrating oxytocin and ovarian hormones signs.

Source: Rockefeller University

In animals with social structures, the impulse to reproduce is a complex process; Registered by the brain, it is influenced by internal signals, such as hormones and external factors, such as interactions with potential couples.

An area that has long plays a fundamental role is the prefrontal cortex (PFC). Located just behind the forehead, this node governs several aspects of social behavior.

In a recent article in cells, researchers in the Molecular Biology Laboratory of the Rockefeller University, directed by Nathaniel Heintz, have determined how a PFC subregion influences the reproductive disc in mice: through a hormonally primary cortical circuit that controls how and when female mice seek to mate with men.

The circuit, which connects to multiple layers of the brain, is stimulated by both the oxytocin of the “love hormone” and for ovarian hormones.

“The circuit integrates hormonal states with the recognition of potential partners to orchestrate complex cognitive behaviors,” says Ines Ibaénez-Tallon, associate professor of research in the laboratory and co-author of the study.

Interestingly, male mice also have this circuit, but their activation has the opposite effect in them: they become less interested in mating.

“This shared circuit is flexibly sculpted by both hormonal and biological sex to produce specific social behavior patterns,” says Senior Kun Li co -author, a former pH.D. Student in the laboratory and now associated professor at the School of Life Sciences of the University of Tsinghua.

“I could help explain why sexual motivation and social interest fluctuate between reproductive states and differ between sexes.”

Sexual dimorphism in the brain

The document is based on previous findings of the laboratory. In 2014, the researchers discovered a new type of brain cell in the medial prefrontal cortex (MPFC) that they called neurons that express the oxytocin receptor (oxtrins).

Oxytocin is a hormone linked to the union of all kinds: maternal, family, romantic, social. In the mice, the team found, the oxtrins cortical circuit promoted the receptivity to mating, but only in women, and only during the estrus, or the fertile period.

Intrigued by the idea that a cell of cell identical to male and females mice could affect them very differently, researchers, led by Heintz and Ibañez-Tallon, conducted additional studies that further documented the unequal influence of Oxtrin.

In a 2016 study, they found that the activation of oxtrins reduces the behavior related to anxiety in male mice but not in female mice. Although he did not alter anxiety levels in female mice, however, he made women show more social preference for male mice.

Although both discoveries pointed out a fundamental role for MPFC in adaptive social behaviors that depend on reproductive states, “the way in which MPFC detects internal hormonal states and regulates flexible control over social behavior results is not clear,” says Li.

For the current study, some of which were carried out at the University of Tsinghua, the researchers aimed to immerse themselves in those details.

The circuit

The previous research had located oxytocin sensitive neurons in multiple layers of the MPFC. For the current study, Li and his colleagues began to layer 5, which sends information to other areas of the brain. They identified neurons in this layer that expressed the Cacna1H gene, which produces calcium channels, electrical switches that neurons use to communicate.

Then they tracked their connections in the region of the anterior hypothalamic nucleus (AHN) of the hypothalamus, an ancient part of the brain that regulates basic needs such as hunger, thirst and sleep, as well as sexual behaviors.

Then they used a variety of advanced techniques to monitor neuronal activity in the brains of female mice as they passed through a complete corner cycle, the equivalent of a human menstrual cycle, and interacted with male mice.

Cacna1H+ neurons turned out to be highly receptive to ovarian hormones, illuminating when the mice were fertile. During this period, female mice searched for male mice, rejected them less and showed greater sexual receptivity.

By putting everything, the team determined that Cacna1H+ neurons are a critical subset of hormonally influenced neurons that respond to the indications of oxytocin through oxtrins, which receive social signals and AHN, which reads internal signals, resulting in socio -art behavior.

However, manipulating neurons changed that behavior of diametrically opposed forms in mice. When Li ignited the cacna1h neurons in female mice during the non -fertile period, the mice began to act as if they were hormonally prepared to mate. And when he inhibited the neurons during the estrus, the mice lost all interest.

The opposite was true for male mice, whose brain activity was also monitored. Silence the cacna1H+ neurons in male mice reduced their interest in female mice, and were faster to try to mate with them. And the activation of neurons suppressed male sexual behaviors.

The circuit also seems to have a feedback circuit. That is, the neural activity of Cacna1H+ can not only initiate behavior, but the behavior can activate the neurons themselves.

In stine females, these neurons were strongly activated by male signs and promoted socioxual interest and sexual receptivity, while in men these neurons did not respond to female signals, and male mice showed a reduced interest.

“It’s fascinating,” says Ibañez-Tallon. “Even when neuronal circuits, neuronal populations and molecular components are identical, perfecting only at their expression levels, the system can produce remarkably different functional results.”

While this study focused on ovarian hormones, in the future they will analyze the influence of testosterone, which has well -established links with depression, schizophrenia, anxiety and other disorders.

“Given the surprisingly different functional roles of Cacna1H+ neurons in men, testosterone is likely to play a key role in its development or response capacity,” says Li.

“This line of research could provide valuable information on the specific regulation and vulnerability of the sex of social and emotional behaviors.”

On this neuroscience research news

Author: Katherine Fenz
Source: Rockefeller University
Contact: Katherine Fenz – Rockefeller University
Image: The image is accredited to Neuroscience News

Original research: open access.
“Integrating the reproductive states and social signs in the control of the socio -excess behaviors” of Nathaniel Heintz et al. Cell

Abstract

Integrate reproductive states and social signals in the control of socio -out behaviors

Female socioly, essential for survival and reproduction, are modulated by ovarian hormones and are triggered in the context of appropriate social signals.

Here, we identify the primary neurons of the medial prefrontal cortex that expresses CACNA1H (MPFCCACNA1H+) that make up hormonal states with the recognition of potential couples to orchestrate these complex cognitive behaviors.

The bidirectional manipulation of the MPFCCACNA1H+ neurons changes the social behaviors aimed at the opposite sex between the estrus and the Diestrus females through previous hypothalamic outputs. In men, these neurons fulfill opposite functions compared to estrus females.

Miniscope images reveal a mixed representation of autoestros and sex states social objective in different subpopulations of MPFCCACNA1H+, with biased codification of opposite sex signals in women and stan males.

Mechanically, the positive regulation of CACNA1H induced by ovary hormones improves the excitation of T -type rebound after inhibition of oxytocin, which drives the specific activity changes of the stan and the sexually dimorphia of the mpfcaccona1H+neurons.

These findings discover a prefrontal circuit that integrates internal hormonal states and objective sex information to exercise control from sexually bivalent sexually on adaptive social behaviors.