Researchers examine how touch can trigger our emotions

While touch always involves awareness, it also sometimes involves emotion. For example, picking up a spoon triggers no real emotion, while feeling a gentle caress often does. Now, scientists, including LJMU’s Professor Francis McGlone, describe a system of slowly conducting nerves in the skin that respond to such gentle touch, in the Cell Press journal Neuron.

Using a range of scientific techniques, investigators are beginning to characterise these nerves and to describe the fundamental role they play in our lives as a social species—from a nurturing touch to an infant to a reassuring pat on the back. Their work also suggests that this soft touch wiring may go awry in developmental disorders such as autism and anorexia.

The nerves that respond to gentle touch, called c-tactile afferents (CTs), are similar to those that detect pain, but they serve an opposite function: they relay events that are neither threatening nor tissue-damaging but are instead rewarding and pleasant.

“The evolutionary significance of such a system for a social species is yet to be fully determined,” says Professor Francis McGlone. “But recent research is finding that people on the autistic spectrum do not process emotional touch normally, leading us to hypothesise that a failure of the CT system during neurodevelopment may impact adversely on the functioning of the social brain and the sense of self.”

For some individuals with autism, the light touch of certain fabrics in clothing can cause distress. Temple Grandin, an activist and assistant professor of animal sciences at Colorado State University who has written extensively on her experiences as an individual with autism, has remarked that her lack of empathy in social situations may be partially due to a lack of “comforting tactual input.”

Professor McGlone, who is a Professor in Cognitive Neuroscience at the School of Natural Sciences & Psychology, also notes that deficits in nurturing touch during early life could have negative effects on a range of behaviours and psychological states later in life.

Further research on CTs may help investigators develop therapies for autistic patients and individuals who lacked adequate nurturing touch as children. Also, a better understanding of how nerves that relay rewarding sensations interact with those that signal pain could provide insights into new treatments for certain types of pain.

Professor McGlone believes that possessing an emotional touch system in the skin is as important to well-being and survival as having a system of nerves that protect us from harm.

“In a world where human touch is becoming more and more of a rarity with the ubiquitous increase in social media leading to non-touch-based communication, and the decreasing opportunity for infants to experience enough nurturing touch from a carer or parent due to the economic pressures of modern living, it is becoming more important to recognize just how vital emotional touch is to all humankind.”

The paper Discriminative and Affective Touch: Sensing and Feeling is available at: http://www.cell.com/neuron/home

Read the story in the National Geographic

Contact Professor McGlone to learn more about his research via the School of Natural Sciences and Psychology website

Clare Coombes, Press and Publications Officer, Liverpool John Moores University, T: 0151 231 3004 press@ljmu.ac.uk 

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