Transport Response is a filial-specific behavioral response to maternal carrying in C57BL/6 mice
- PDF / 741,492 Bytes
- 11 Pages / 595.28 x 793.7 pts Page_size
- 41 Downloads / 163 Views
RESEARCH
Open Access
Transport Response is a filial-specific behavioral response to maternal carrying in C57BL/6 mice Sachine Yoshida1,2, Gianluca Esposito1, Ryuko Ohnishi1, Yousuke Tsuneoka1, Shota Okabe3, Takefumi Kikusui3, Tadafumi Kato4 and Kumi O Kuroda1*
Abstract Background: A mother carries her young in many altricial mammals, such as cats, lions, rats and mice. During maternal carrying, the transported young assume a compact posture. We have recently shown that, in both humans and mice, the carried infants immediately calmed down and showed reductions in heart rate, distress vocalizations, and voluntary movement. The loss of the calming response in mouse pups hindered maternal retrieval efficacy. These findings suggested that the infant calming response functioned to reduce the maternal burden of carrying and was therefore conserved in a variety of mammalian species. However, it remains unclear how and when each component of this calming response develops and whether it is a filial-specific behavior. Results: We dissected various components of the carrying-induced responses in mouse pups, collectively called the “Transport Response” herein. We showed that during the second postnatal week, pups exhibited characteristic compact posture with limb ventroflexion. The body trunk remained paradoxically pliable, suggesting complex neural regulation throughout the body. Pups also showed an increased pain tolerance to a tail pinch during the Transport Response. Analyses of the developmental courses of distinct components of the Transport Response revealed the independent regulation of each component: in the first postnatal week, the cessation of ultrasonic vocalizations was exhibited prominently; in the second postnatal week, immobilization reached its peak; and toward the third postnatal week, the postural component became fully matured. At the end of the third postnatal week, when the pups are able to transport by themselves, the pups no longer exhibited the Transport Response. Conclusions: This study has revealed the mouse Transport Response as a complex set of behavioral and physiological components, each of which has a specific postnatal time window but is orchestrated in a well-matched manner with the maturation of ambulatory ability in the pups. These findings collectively indicate that the Transport Response is a filial-specific, innate behavioral reaction and is distinct from a simple reflex or defensive freezing response. The Transport Response could be a novel index of primitive filial attachment behaviors, acting to smooth mother-infant interaction. Keywords: Mouse pup, Transport response, Calming response, Filial behavior, Maternal carrying, Mother-infant relationship, Parental behavior
Background Mammalian young are born immature and require intense parental care to grow up. Maternal behavior involves the provision of milk, body cleaning, thermoregulation, and protection from environmental hazards. In altricial species, newborns have limited ambulatory ability, and mothers often carry their young to
Data Loading...
