This chapter highlights mesolimbic dopamine (ML-DA) system as central to the experiences of affiliation, attachment urge when under threat, attachment urge during experience of safety, and to the distress of isolation and/or submission. As the midbrain defense centers hold the capacity for stress-induced analgesia (SIA), the tendency to dissociation, which is established with disorganized attachment in very early life, is considered to be secondary to modifications of their sensitivity. Trauma survivors have a default setting that keeps them in threat mode, whether triggered easily by memories of physical danger or separation distress. In a secure attachment relationship, the child can learn the rewards of interaction without threat. The frozen indecision is replaced by a disconnection from the experience of the moment, which relieves the distress. Environmental stress alters the nursing behavior of the mother rat so that she ceases to do so much licking/grooming.