PhD Scientific Days 2022

Neurosciences I. (Poster discussion will take place in the Aula during the Coffee Break)

A thalamo-preoptic pathway promoting social touch

Text of the abstract

We previously identified the posterior intralaminar thalamic nucleus (PIL) as a relay station of socially relevant sensory information innervating and activating oxytocin-secreting neurons upon social encounter. Here, we addressed to characterize the exact role of the PIL neurons and their projections to the preoptic area of the hypothalamus in the control of the social behavior.
First, we determined the effect of chemogenetic stimulation of PIL neurons on social interactions between familiar adult female rats. The projections of PIL neurons were analyzed using anterograde tract-tracing. The selective chemogenetic stimulation of the preoptic area-projecting PIL neurons was performed using double viral injections and also by CNO administration directly into the preoptic area.
PIL projects to several socially implicated brain regions, such as the medial amygdala, the medial preoptic area and the infralimbic cortex. Chemogenetic stimulation of the PIL resulted in the activation of previously anatomically identified target areas and increased the duration of social grooming. Direct contact during social interaction caused the largest increase in the activity in the medial preoptic area. Specific chemogenetic stimulation of the PIL-preoptic pathway led to elevated direct social contact.
The results suggest that posterior thalamic PIL neurons convey socially relevant information to a variety of different forebrain centers, among which the preoptic area is involved in the processing of physical contact.
Support: Doctoral Student Scholarship Program of the Co-operative Doctoral Program of the Ministry of Innovation and Technology, Excellence Program of the Semmelweis University, Gedeon Richter Plc. Centenary Foundation, EFOP-3.6.3-VEKOP-16-2017-00009, NKFIH-4300-1/2017-NKP_17-0002 and OTKA K134221.