UNRAVELLING THE ROLE OF SOCIAL TOUCH IN EMPATHY DEVELOPMENT

Touch is essential for the development and maintenance of social bonds across a wide range of species. Indeed, our lab recently demonstrated that the inhibition of a specific subclass of sensory fibers involved in light touch perception, the C-LTMRs, leads to a loss of sociability in mice and consequently impairs prosocial behaviors.
Among these behaviors, consolation toward distressed individuals is common in humans, great apes, canids, corvids, and elephants, but it had not been reported in rodents until lately. In 2021, Wu’s team observed an increase of allogrooming between two cage-mates mice following a major stress experienced by of one of them. These findings suggest that mice may display empathetic responses, and engage in prosocial touch to soothe a distressed congener.
The main goal of my thesis is to identify the mechanism by which touch regulate empathy development. To test this, I used different genetic strategy to modulate somatosensory fibers, including C-LTMRs, before and during a consolation test inspired by Wu et al. My results indicate that when these fibers are inhibited, mice exhibit less allogrooming towards a distressed conspecific.
In parallel, I recorded the neural activity of diverse brain areas supposed to be involve in empathy by fiber photometry during somatosensory stimuli. I observed that the anterior cingulate cortex and the locus coeruleus are both activated by light dynamic sensory stimuli.
My study advances our understanding of the neural coding and regulation of empathy related prosocial behaviors.