title: Infant calming responses during maternal carrying in humans and mice.
abstract: BACKGROUND
  Mother-infant bonding is the earliest and most critical social relationship of mammalian infants. To promote this bond, infants have innate behaviors to seek maternal proximity and protest upon separation via communication with the mother vocally and through body movement. However, the physiological mechanisms regulating these infant behaviors remain largely undefined.
  
  
  RESULTS
  Here we show a novel set of infant cooperative responses during maternal carrying. Infants under 6 months of age carried by a walking mother immediately stopped voluntary movement and crying and exhibited a rapid heart rate decrease, compared with holding by a sitting mother. Furthermore, we identified strikingly similar responses in mouse pups as defined by immobility and diminished ultrasonic vocalizations and heart rate. Using pharmacologic and genetic interventions in mouse pups, we identified the upstream and downstream neural systems regulating the calming response. Somatosensory and proprioceptive input signaling are required for induction, and parasympathetic and cerebellar functions mediate cardiac and motor output, respectively. The loss of the calming response hindered maternal rescue of the pups, suggesting a functional significance for the identified calming response.
  
  
  CONCLUSIONS
  Our study has demonstrated for the first time that the infant calming response to maternal carrying is a coordinated set of central, motor, and cardiac regulations and is a conserved component of mammalian mother-infant interactions. Our findings provide evidence for and have the potential to impact current parenting theory and practice, since unsoothable crying is the major risk factor for child abuse.
authors.affiliation: Unit for Affiliative Social Behavior, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Esposito
authors.forename: Sachine
authors.initials: S
authors.lastname: Yoshida
authors.forename: Ryuko
authors.initials: R
authors.lastname: Ohnishi
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Tsuneoka
authors.forename: Maria Del Carmen
authors.initials: Mdel C
authors.lastname: Rostagno
authors.forename: Susumu
authors.initials: S
authors.lastname: Yokota
authors.forename: Shota
authors.initials: S
authors.lastname: Okabe
authors.forename: Kazusaku
authors.initials: K
authors.lastname: Kamiya
authors.forename: Mikio
authors.initials: M
authors.lastname: Hoshino
authors.forename: Masaki
authors.initials: M
authors.lastname: Shimizu
authors.forename: Paola
authors.initials: P
authors.lastname: Venuti
authors.forename: Takefumi
authors.initials: T
authors.lastname: Kikusui
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Kato
authors.forename: Kumi O
authors.initials: KO
authors.lastname: Kuroda
mesh_terms: D017677:Age Distribution; D000818:Animals; D001007:Anxiety; D003448:Crying; D005260:Female; D006339:Heart Rate; D006801:Humans; D007223:Infant; D018730:Infant Behavior; D007231:Infant, Newborn; D008297:Male; D051379:Mice; D009043:Motor Activity; D009068:Movement; D009769:Object Attachment; D011434:Proprioception