Early Social Enrichment Improves Social Motivation and Skills in a Monogenic Mouse Model of Autism, the Oprm1^−/− Mouse

Figure 1

Mean number (+SEM) of ultrasonic vocalizations (USVs) emitted by 8-day-old pups of different experimental groups, when isolated in clean (CLEAN) or in their own home-cage (NEST) bedding for 5 min. : 11–15 per group. µ-KO-L: Oprm1^−/− pups reared by their mother [CLEAN: 9 males + 6 females; NEST: 8 males + 5 females]; µ-KO-L+L: Oprm1^−/− pups reared by their mother plus a second lactating female [CLEAN: 4 males + 7 females; NEST: 6 males + 5 females]; WT-L: Oprm1^+/+ pups reared by their mother [CLEAN: 8 males + 6 females; NEST: 4 males + 8 females]; WT-L+L: Oprm1^+/+ pups reared by their mother plus a second lactating female [CLEAN: 7 males + 6 females; NEST: 6 males + 6 females]. Discrimination of clean versus nest bedding: ^⁎, ^⁎⁎, and ^⁎⁎⁎.