I've always been a massage nut. Many years ago I had some formal training, and I always feel totally rejuvenated by the too-infrequent massages I occasionally get. This item in the Journal of Neuroscience from Guzzetta et al. makes perfect sense to me. I'll bet that a shadow of these early effects of massage seen in infants still occur in adults. The brain growth factor (IGF-1) enhanced by massage in infants is also associated with brain plasticity in adult humans:
Environmental enrichment (EE) was shown recently to accelerate brain development in rodents. Increased levels of maternal care, and particularly tactile stimulation through licking and grooming, may represent a key component in the early phases of EE. We hypothesized that enriching the environment in terms of body massage may thus accelerate brain development in infants. We explored the effects of body massage in preterm infants and found that massage accelerates the maturation of electroencephalographic activity and of visual function, in particular visual acuity. In massaged infants, we found higher levels of blood IGF-1. Massage accelerated the maturation of visual function also in rat pups and increased the level of IGF-1 in the cortex. Antagonizing IGF-1 action by means of systemic injections of the IGF-1 antagonist JB1 blocked the effects of massage in rat pups. These results demonstrate that massage has an influence on brain development and in particular on visual development and suggest that its effects are mediated by specific endogenous factors such as IGF-1.