cientists reveal the secret of cuddles 19:00 28 July 02 NewScientist.com news service Scientists have discovered why being cuddled feels so good - human skin has a special network of nerves that stimulate a pleasurable response to stroking.

The revelation came after doctors realised that a woman with no sense of touch still felt a "pleasant" sensation when her skin was caressed.

Normal touch is transmitted to the brain through a network of fast-conducting nerves, called myelinated fibres, which carry signals at 60 metres per second. But there is a second slow-conducting nerve network of unmyelinated fibres, called C-tactile (CT), the role of which was unknown. The CT network carries signals at just one metre per second.

"It must be used for unconscious aspects of touch because it is so slow," says Håkan Olausson, who led the study at the Department of Clinical Neurophysiology at Sahlgrenska University Hospital, Sweden. "It seems the CT network conveys emotions, or a sense of self."

"This study definitely helps our understanding of how touch systems work," says Brian Fiske, assistant editor at Nature Neuroscience. "The researchers were very fortunate to have found a patient who had lost the main touch receptors but still had the slow CT fibres."

Below the nose

Scientists have known for some time that myelinated nerve fibres transmit information about touch, such as its strength and position. But the function of CT fibres was a mystery. This was because it is impossible to distinguish the CT fibre signals from those of the continuously activated fast myelinated fibre.

The patient examined by the Swedish researchers had a disorder that left her with no myelinated touch fibres in her body below the level of her nose. But her CT fibres remained intact.

Olausson stroked the patient's arm and hand with a paintbrush. Although she could not feel touch, tickle or vibration, the patient said she experienced a "pleasant" pressure when her arm was caressed with a paintbrush.

MRI scans of her brain revealed that the stroking activated insular region of the cerebral cortex associated with emotional response.

Hairy skin

The researchers concluded that the CT system may be of important for emotional, hormonal and behavioural responses to tactile stimulation.

"They are the opposite to pain fibres and give the message that the touch is non- harmful," Olausson told New Scientist. "Stimulation of CT fibres is probably linked to the release of pleasure hormones, like oxytocin. Studies have shown that if you stroke infants, their levels of oxytocin increase."

Further research by the Swedish team suggests that CT fibres are only present in hairy skin - the patient showed no response to the palm of her hand being stroked.

Olausson speculates that because the hand is used for so many critical tasks, it needs to be very sensitive to touch and therefore has a greater density of faster- conducting nerves.

Journal reference: Nature Neuroscience (DOI: 10.1038/nn896)

-- Anonymous, July 29, 2002

Answers

Yet another scientific reason why massage feels so good and is good for you! :)

-- Anonymous, July 30, 2002

If you have neural problems its not enjoyable. It can actually be downright painful. :>) "Cuddles" and massages for me can be like hot coals. Thats why I use pain killers descretly before intimate encounters.

-- Anonymous, July 31, 2002

Holy smokes! I can't imagine a life in which simple touch, let alone not so simple touch, is not pleasurable. Poor Jay. Being a fairly tactile person this would be unendurable for me. I always touched my babies a lot..smoothing lotion all over after baths, massaging their bodies, tickling, any kind of loving touch you can imagine appropriate between a mother and child. There were many articles in the parent magazines about the therapeutic benefit of touch between parent and child and I thoroughly believe it. I still rub the boys backs, play with their hair, stroke them to sooth them before bed or after a crisis be it a fall, or discipline, or a fight with the sibling. Often just the act of holding them close is beneficial, especially to my eldest. Even at five he can just fold himself into my arms and melt into me for comfort. There is NO feeling like that. Have you ever noticed the feeling of well being that comes from simply having a friend put their arm around your shoulders in a friendly way? One of life's more innocent and serene pleasures, eh?

-- Anonymous, July 31, 2002

Wow Jay, that sucks rocks! One of my classmates in massage school has reflex sympathy dystrophy so we had to be very careful to avoid touching her feet or else it would set off an attack.

-- Anonymous, July 31, 2002

I can't imagine it either! And Alison, my girls are pretty much grown and they still come to me at least once a day, and usually several times, for cuddles. They are also very affectionate with their friends, who tend to be the same type of people. It is less so with their male friends being affectionate with each other of course, which is sad, but they do after all live in this dysfunctional culture. The boys are very much more touchie than average American teens though.

When I read this article the first thing I thought of was the little kids in school. How they need that touching, and how teachers are pretty much no longer allowed to touch them. That's messed up.

-- Anonymous, July 31, 2002

I was thinking the same thing EM. My dad used to be a little league coach for my brother and a softball coach for my sister. My dad is great with kids and he frequently gave them a pat on the back, ruffled their hair, and even a hug when needed. Such actions today would probably get him fired as a coach, if not arrested.

-- Anonymous, July 31, 2002

You learn to live with it. I learned to keep it private, especially since my divorce. I leveled with my ex and she was offended by it. She never considered that it was out of my control and that I felt closeness in other ways since it was a lifetime condition. She only felt that it was wrong that she couldn't exhibit to strangers how we felt to each other. Even though the people around us knew of my physical position, emotional bond and commitment, she was more concerned about strangers opinions if she wasn't hanging all over me.

-- Anonymous, July 31, 2002

Now THAT is just messed up. She didn't deserve you, oh Great Worm King.

-- Anonymous, July 31, 2002

Yes, it was messed up, but looking back, I'm glad I encountered her (can't really say "I knew her" :>)

-- Anonymous, July 31, 2002