Deciphering Oxytocin Circuitries Orchestrating Socio-Sexual Behavior – SoSexOT

The present ANR-DFG project was the occasion to bring new technologies to our lab, namely freely moving in vivo calcium imaging, which was used to compliment in vivo electrophysiology recordings. Thus, in order to better tackle the oxytocin-regulated socio-sexual behaviour, we decided to spent significant amount of time to bring these technologies in our lab. The main difficulty relies on the depth of the recorded structures: near 1 cm for both the rats PVN and the SON.

In the course of our study, we obtained the following major results:
4. Oxytocin neurons are activated during social interactions between female rats, principally by direct physical touch.
5. A specific small subpopulation of oxytocin neurons, (parvocellular neurons of the PVN), are preferentially activated by tactile stimulation and these transmit activation to the much larger population of magnocellular oxytocin neurons.
6. Chemogenetic-based selective activation of these parvocellular oxytocin neurons in female rats promoted social interaction with an unfamiliar female. Conversely, the selective inhibition of these neurons suppressed social interactions.

All the results obtained in the course of the project have or will be published in peer reviewed journals.

5 commons articles have been published around this project by the project coordinators

Reproduction is an essential feature of living organisms and is largely modulated in vertebrates by hypothalamic neuropeptide oxytocin (OT) and its homologs. In mammals, reproductive function is realized by complex socio-sexual (SS) behaviors, which can be mechanistically divided into precopulatory and copulatory behaviors, both modulated by OT. However, precise OT circuits underlying OT effects are far from clear. Although there are no doubts that OT promotes sexual behavior, the OT circuits orchestrating precopulatory behavior via forebrain regions are largely unknown. To address these questions, we will employ a recently developed genetic technique (called “virus-based Genetic Activity-Induced Tagging” and abbreviated as vGAIT) to tag only those OT neurons which were activated during precopulatory and copulatory behaviors of rats. Using this technique, we will elucidate spatial distribution of such OT neurons in the hypothalamus, their phenotype and their projections as well as identify structures receiving input from tagged OT neurons in the forebrain, brainstem, and spinal cord. In parallel, in freely moving rats, we will record the activity of these OT neurons to elucidate their properties and excitability during SS behavior. Based on anatomical data, we will stimulate axonal OT release in those forebrain structures which are functionally related with SS behavior. At the end, using optogenetic and pharmacogenetic techniques, we will activate or inhibit entire populations of tagged OT neurons to monitor changes in SS behavior. The expected data will be entirely novel and will provide mechanistic insights into the physiology of the OT system in the context of SS behavior. Our proposal is highly relevant to human health as it will provide a basis for pathogenesis and possible pharmacological intervention in patients experiencing problems with sexual arousal and reproductive function.