ICR mice pups established CPP when conditioned with their mother or father alone.
ICR mice pups failed to show any preference in mother versus father conditioning.
The pups showed more TH-IR neurons in the VTA when conditioned with their mother or father alone.
The pups showed more OT-IR neurons in the SON when conditioned with their mother rather than father.
The pups showed higher levels of OT and TH in mother versus father conditioning.