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Skin and the Brain: Uncovering New Links
By: Claudia C. Aguirre and Annet King
Posted: September 28, 2012, from the October 2012 issue of Skin Inc. magazine.
While scientific research during the past century has focused on identifying and studying separate somatic structures, functions and conditions, the newest discoveries spanning many disciplines uncover more about relationships between the body’s systems than the individual systems themselves. One area where this research is especially compelling is the ongoing dialogue between skin and the brain.
A reflection of the brain
In utero, both skin cells and brain cells develop from the same kind of embryonic tissue, called ectoderm. In the January 2012 issue of Proceedings of the National Academy of Sciences, researchers at the Stanford University School of Medicine in California conducting a study on mice were able to transform skin cells directly into brain cells, bypassing the stem cell stage, and further demonstrating this fundamental physiological link between skin and the brain.
Throughout life, the skin may be a reflection of changes within the brain, triggered by cascades of brain chemicals that have only recently started to be named and explored. For instance, the rise in adult acne may be linked to stress, which elevates both testosterone and cortisol levels. With natural aging, the decline of estrogen contributes to the loss of collagen and elastin, and the proliferation of hyperpigmentation—and these changes also affect the brain.
The role of oxytocin
Much has been written throughout the past several years about the role of oxytocin—a neuropeptide colloquially called the “love hormone”—relative to being touched. Oxytocin is a neurochemical produced by the brains of both female and male mammals. In animal studies, it is linked with lactation and pup recognition. In the human context, it may be the basis of much bonding, including sexual bonding. The touch that is experienced in a safe, nonthreatening context also releases other feel-good chemicals known as beta-endorphins.
Consider that very few recently divorced people say that they miss the wild, heart-pounding sex of their marriage; instead, they miss the comfy morning spooning, the hugs, the warmth and the familiar aroma of their former partner—in other words, the relaxed physical companionship of married life. In fact, a great deal of mammalian sexual expression may have more to do with oxytocin, which could be called the chemical basis of familial love, versus the simpler reproductive sex hormones of estrogen, progesterone and testosterone.