The current study artificially upregulated maternal touch via the simulated maternal grooming paradigm. This paradigm allows for other variations in maternal care to be better controlled because we manipulate the pups without treating the dams. This allows each dam to care for a mixed litter of SMG-treated and control-handled pups. Past studies have shown that briefly handling the pups can promote additional licking and grooming when the pups are returned to the litter. However, as the entire mixed litter is removed and returned at the same time, it is unlikely that this would induce a difference in maternal care between treatment groups. Therefore, the current study lends strong evidence to the suggestion that the somatosensory stimulation associated with maternal grooming critically regulates male juvenile social play behavior. The pattern of juvenile social play in the current study is consistent with past research investigating the influence of maternal care on later juvenile social play behavior. Previous studies indicate that the amount of maternal anogenital licking is promoted by a pup��s chemosignals. As such, many of the previous studies that examine the influence of maternal care on social play manipulate the dam��s ability to smell in order to reduce the amount of licking and grooming. For example, one study reduced maternal grooming by applying perfume to the pups�� anogenital region and found that perfumed males displayed more social play behavior. Similarly, male offspring of dams treated throughout lactation with intranasal zinc sulfate, which reduces chemoperception by the dam and thereby reduced maternal grooming, engaged in more social play than male offspring of control-treated dams. Separating pups from the dam for 3 hours a day for the first two weeks of life also enhanced play-fighting in male juvenile rats. The development of social play is also influenced by naturally-occurring variations in maternal care. That is, male offspring from dams that exhibited increased levels of pup licking/ grooming and arched-back nursing engaged in less social play than males from low LG-ABN mothers. Consistent with our data, none of these studies found that manipulations of maternal care altered the levels of female social play behavior. Although these studies suggest that variations in maternal care influence play behavior, it is important to note that the dams in these studies also displayed other differences in maternal care, like time spent in the nest or the time spent arched-back nursing. Nonetheless, these prior data suggest that that reducing maternal contact increases juvenile social play behavior. Our current data may be consistent with that concept. Specifically, we used the SMG paradigm to mimic an increase in somatosensory stimuli associated with maternal contact. Neonatal males receiving SMG exhibited reduced levels of social play behavior during the juvenile period. While we cannot be control for the possibility that SMG provided to males and females during the neonatal period altered mother-pup interactions, our current data along with the previous findings discussed above suggest that there may be an inverse relationship between maternal licking and grooming and the levels of future juvenile play behavior in males. Juvenile social play ASC4 readily forms amyloid aggregates, as confirmed interactions in living and fixed cells appears to help prepare for adult social behaviors such as male sexual and aggressive behaviors. The actions of a male rat during juvenile social play can be used to predict his aggressiveness as an adult.