Laboratory Visualizes the Brain Circuits Involved in Anxiety and Aggressiveness

Picture Source. IN-CSIC-UMH -Three-dimensional reconstruction of oxytocin and vasopressin neurons in the hypothalamus.

Appro. May 21, 2021. A study by the IN-CSIC-UMH visualizes the pathways of the proteins oxytocin and vasopressin, involved in the regulation of complex social behaviors like Anxiety and Aggressiveness.

A study carried out at the Institute of Neurosciences (IN-CSIC-UMH) , a mixed center of the CSIC and the Miguel Hernández University, in Spain, has managed to reconstruct in 3D with unprecedented cellular resolution the oxytocin and vasopressin circuits of the brain of a developing mouse. Alterations in these circuits could be at the base of mental disorders such as autism, anxiety and social aggressiveness or schizophrenia. This advance, carried out by researchers Pilar Madrigal and Sandra Jurado and published in the journal Communications Biology, has been possible thanks to the combination of techniques to make the brain transparent and high-resolution microscopy.

With a very similar structure, oxytocin and vasopressin are two highly conserved neuropeptides in the evolutionary scale that are involved in the regulation of complex social behaviors such as maternal behavior or couple bonds.

Although it is unknown how oxytocin and vasopressin interact in the brain, numerous studies in animals and humans suggest that alterations in these circuits may be at the basis of mental disorders characterized by deficits in social interaction, such as autism, anxiety, and social aggressiveness or schizophrenia.

Modulation of Social Behavior

Thanks to this hormone we are able to maintain affective relationships with our peers. And one of the most primitive and strongest relationships in mammals is precisely the close relationship between a mother and her children. In addition, oxytocin is also popularly known as the love hormone, since it promotes social contact, partner preferences and subsequent attachment. In addition, it produces a feeling of security and well-being and reduces stress.

Similarly, vasopressin promotes social contact, mate preference, and attachment, modulates territorial behaviors against potential same-sex rivals, and increases sexual and reproductive attraction and behaviors.

The Social “Wiring”

In this study, Madrigal and Jurado have implemented the IDISCO + clarification technique, which allows removing a large part of the lipid (fat) content of the brain without damaging its structure to make it transparent.

Thanks to this methodology, the researchers have been able to make a precise classification of the cells that synthesize oxytocin and vasopressin in deep nuclei of the brain, such as the hypothalamus.

"It is likely that these dynamic adaptations allow modulating the levels of oxytocin and vasopressin in different regions of the brain according to the stage of development, thus contributing to the improvement of the neural circuits that are at the base of social behaviors," the researchers highlight.

Just as scientists now know that a deficiency of the Leptine, generates symptoms of "Insatiable Hunger" in people and respectively endogenous and exogenous obesity; it is also correlated to deficiencies of some digestive enzymes, now the knowledge of these circuits will allow to prevent and to know the threshold over which human behavior becomes hostile and dangerous for itself and for society.

Science is now moving closer and closer to vaccines or treatments for chemical imbalances that affect human behavior.