Sometimes When We Touch

(Editor’s note: This article is from a past issue of Brain World magazine. If you enjoy this article, please consider a print or digital subscription!)


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. Below we explore some of the ways touch can have a positive effect on infant development, school performance, depression and anxiety, as well as therapeutic applications in patients with disorders such as autism and Alzheimer’s.

Infants

“Touch is the first modality to develop in utero,” says Hertenstein. “It is just as important as nutrition, in some ways, in early life.” Research has shown that babies who receive nurturing touch are more likely to form healthy attachments to their caregivers, to gain weight and thrive during infancy. According to Tina Allen, founder of the LiddleKidz Foundation and also the nation’s first pediatric massage program at Children’s Hospital in Los Angeles, infant massage has been shown to help with colic, sleep regulation, brain development and sensory integration.

Children

Best-selling author, scientist, and autism activist, Dr. Temple Grandin, has spoken of the deep touch pressure device, or “squeeze machine,” that she developed to help overcome her own problems with oversensitivity to touch, a common phenomenon in those with autism. Grandin’s own research with the machine showed that children with autism as well as those with attention deficit hyperactivity disorder both responded positively to it. In a similar study, Field and her team found that after back rubs, severely autistic children performed better in school, staying on task and paying closer attention. When massaged at home by their parents, the same kids had fewer sleep issues. In another study, Field looked at preschoolers and the amount of affectionate touch they received from their caregivers and teachers. Field’s researchers found that kids who received a back rub before an IQ test performed much better than when they went without a pre-test massage. These days, touching in a school setting is a fraught topic. While she acknowledges the sensitive nature of touching children, Field says that the benefits shouldn’t be overlooked. “Kids are missing out. They are getting touch deprived,” says Field.

Adolescents

Field and her team conducted studies comparing teens in Paris and Miami to measure how much they touched one another during social interactions — in this case, while hanging out at McDonald’s. The results showed that French teens of both genders engaged in all sorts of affectionate touch — from stroking and back rubbing to holding hands or just throwing their arms around one another’s shoulders. “In this country,” says Field, “we found more self-stimulating — flipping the hair, cracking knuckles and stroking knees.” Tactile stimulation increases serotonin, which counters aggressive behaviors, says Field. The implication, she says, is that a lack of pleasant social touch among U.S. teens may be a contributing factor in school violence. “Studies show that if you deprive primates of touch, they become extremely aggressive and violent. They will actually kill each other.” In addition, as teen pain syndromes — fibromyalgia, lower back pain, migraine, and depression — rise in the United States, stimulating an increase in serotonin through massage may be a powerful tool to help combat these disorders.

Adults

Studies show that touch-deprived adults suffer decreased immune response, says Field. When cortisol (the stress hormone) is left unchecked, it attacks the body’s natural killer cells, which are instrumental in fighting of bacteria and viruses. The natural killer cells are also vital in fighting cancer cells. Touch can boost serotonin and lower cortisol. Field’s studies found that 30 minutes of massage can lower levels of the stress hormone cortisol by almost 30 percent.

The Elderly

“If there is any age group who experiences an excessive deprivation of touch, it’s old age,” says Hertenstein, who says that this touch deprivation can result in depression and anxiety among older adults. Field notes an interesting study showing that elderly research subjects who served as massage therapists for infants did better when they massaged the infants than when they were massaged themselves. “Their serotonin levels went up, stress hormones decreased and they made fewer trips to the doctor,” says Field. The subjects also became more social. According to research published in the Archives of Psychiatric Nursing, therapeutic touch has been shown to reduce anxiety and stress and effect psychological relaxation in patients with Alzheimer’s disease.


Although the scientific benefits of touch are only just beginning to be discovered, initial research — and common sense — tells us that we should incorporate more touch, no matter what stage of life we are in.

(Editor’s note: This article is from a past issue of Brain World magazine. If you enjoy this article, please consider a print or digital subscription!)

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