A hormone helps suppress interactions with known people in order to encourage new ones

A study led by researchers at the Institute of Neurosciences (IN), a joint center of CSIC and Miguel Hernández University, has described for the first time in mice that a Mechanism that connects social memory with preferences when interacting with other congeners. The work published in the journal cellfound that a group of neurons secretes a hormone that helps suppress interactions with already known individuals in order to encourage preference for new ones.

The social preferences They prompt an individual to make the decision, under certain circumstances, to interact more with one member of their species than with another. The motivation to interact with new people is a fundamental quality to live in society and to interact properly. Until the publication of this study, one of the great unknowns about this preference for new individuals was whether it arose from neural circuits that promoted motivation for novelty or, on the contrary, there were circuits that suppressed interaction with already known individuals.

Neural Circuits and Social Preference

With the aim of expanding knowledge of the neural circuits that control social preference and solving this unknown, the Laboratory for Cognition and Social Interactions was set up at IN, led by the CSIC researcher Felix Leroy, led a study conducted on rodents. This work, in which researchers from the Universities of Columbia and Washington (USA) collaborated, describes a mechanism responsible for suppressing interactions with people who are already known in order to encourage preference for the new.

Researchers have discovered a group of neurons in the prefrontal cortex that are characterized by producing corticotropin-releasing hormone (CRH) and sending their axons to the lateral septum area. This region is important because it regulates the so-called motivated behavior: the search for food, security, comfort and socializing with peers.

Using a combination of electrophysiological, chemogenetic, optogenetic, and gene silencing techniques, the authors found that when mice sense familiarity with an individual, neurons in the prefrontal cortex fire, releasing CRH into the neurons from the region of the lateral septum. This activates the lateral septum and reduces interaction with familiar people. Therefore, the release of the CRH hormone helps create the preference for social novelty. The results of this research are protected by a patent application.

As Leroy explains: “Contrary to what happens in adult rodents, Hatchlings prefer to bond with and stay close to their kin. This is very useful from an evolutionary point of view as it guarantees the survival and correct development of the offspring.”

However, he adds, “This preference must change in the postnatal period in order to promote preference for social novelty and thus acquire adult social behavior.” prefrontal cortex facilitates this process during the first two weeks of life. Social behavior change during development“, explains the IN researcher.

possible treatments

Up to 1% of the population can suffer from the so-called disease avoidable personality disorderwhich clinically manifests as a form of extreme introversion. One of the most common anxiety problems in children is also separation anxiety, an unusually strong fear of being separated from loved ones that severely interferes with their daily lives.

In this sense, the IN researchers suggest that a lack of CRH in the prefrontal cortex or in its receptor in the area of ​​the lateral septum could lead to changes in social interactions: “We know that certain changes in the gene encoding this hormone occur.” have previously been associated with a higher incidence of behavioral disorders,” explains Noelia Sofia de Leon Reyes, CSIC researcher at IN and first author of the article.

“The disorders in social behavior They are commonly associated with the onset of many psychiatric disorders, and we know that the regions examined in our study are dysregulated in various psychiatric disorders,” Leroy points out. Furthermore, the researcher points out that the results of this work open new lines of research that could lead to the development of nCSICevos. Drugs that target the CRH system as a therapeutic target to treat social anxiety disorder and other types of psychiatric disorders associated with abnormal interactions, such as autism or depression.

This work was possible thanks to funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme, the CIDEGENT grant from the Generalitat Valenciana and the Severo Ochoa Foundation. This is an investigation that is part of the project Motivated Behaviors (H202O-ERC-STG/0784, no. 949652), which aims to investigate the role of the lateral septal nucleus in the regulation of motivated behaviors with the aim of unveiling the changes that occur in social behavior deficit-related disorders.