The skin is our largest organ. Its nerve endings and pressure receptors are tactile pathways, activated through touch, which our brain uses to interpret and explore the world around us. But recent research suggests that the brain’s response to touch serves an even wider purpose, providing critical stimulation during all stages of life.
“The importance of touch can’t be understated,” says Dr. Matt Hertenstein, an experimental psychologist at Indiana’s DePauw University. “We see touch develop as one of the first modalities when the baby is in the mother’s womb. It is our very first connection to the world,” says Hertenstein. “It takes precedence early and never leaves us.” When we are touched, or when we touch something or someone, pressure receptors under the skin send signals to the brain, which responds by undergoing a series of physiological reactions.
How our brains process touch is the subject of research by Dr. Edmund Rolls and his colleagues at Oxford University’s Center for Computational Neuroscience. Using functional magnetic resonance imaging (fMRI), Rolls and his team determined that pleasant touch activates the brain’s orbitofrontal cortex — the area of the brain which processes information related to reward and decision-making.
They also found that different areas of orbitofrontal cortex were activated by pleasant versus painful touches. The vagus nerve — the tenth cranial nerve, which wanders from the brainstem to the colon — is also activated with pleasant touch. The vagus nerve is the main nerve controlling the body’s parasympathetic nervous system.
Giving and receiving so-called pleasant touch triggers a variety of physiological responses, says Hertenstein. It reduces the cardiovascular stress response — lowering heart rate, blood pressure and the stress hormone cortisol — and triggers the brain’s release of oxytocin, a neuropeptide that promotes feelings of well-being, devotion, and bonding.
Touch is inherently reciprocal. It’s impossible to touch someone or something without being touched. And research shows that the benefits of touch are available whether on the giving or receiving end. For example, oxytocin is released not only when we receive pleasant touch, but when we give pleasant touch to others, says Hertenstein.
So what do researchers mean when they say “pleasant touch”?
“What’s really key is the pressure in touch — you need to have moderate pressure,” says Dr. Tiffany Field, director of the Touch Research Institute at the University of Miami School of Medicine. “That is one of the reasons that a moderate handshake feels better than a flimsy shake, or a bear hug feels better than a superficial hug — the pressure receptors are stimulated.”
Field points out that pleasant touch can include simple social affection, massage, and even yoga, which she terms a form of self-massage. In fact, Field says that even fast-paced walking can be considered a form of self-massage, as the pressure receptors in the feet are stimulated.
While researchers are just beginning to understand how the brain processes and responds to touch, Field says a number of studies indicate that touch plays an important role throughout our lives.