Why the back? How stroking calms infants and mouse pups

A research group led by Dr. Sachine Yoshida and Professor Hiromasa Funato of the Faculty of Medicine at Toho University discovered that gently stroking the back reduces spontaneous movement and calms both human infants and pre-weaning mouse pups.
Detailed analyses in mouse pups revealed that continuous stroking led to a decrease in heart rate, promotion of sleep onset, and attenuation of stress responses. In contrast, these effects were not observed in artificially reared mouse pups that had limited physical contact with their mothers. This finding suggests that the soothing response to being stroked develops through physical contact experiences during early postnatal life.
The researchers also found that this response is associated with the Cacna1b gene, which is expressed in the hypothalamus, a region of the brain involved in regulating physiological functions and behavior.
These findings are expected to contribute to a scientific understanding of how early interactions with caregivers influence the physical and psychological development of infants. They may also support the development of evidence-based childcare and early education practices.