May 22, 2014
How Does Touch Trigger Our Emotions, And How Does It Affect Those With Autism?
April Flowers for redOrbit.com - Your Universe Online
Our sense of touch can be simply an awareness, such as picking up a spoon, or it can evoke powerful emotions, such as when we receive a gentle caress.
Researchers are using a variety of scientific techniques to characterize these nerves. The new findings, published in Neuron, reveal the fundamental role these nerves play in our lives as a social species, as well as suggesting reasons why this soft touch wiring might misfire in disorders such as autism.
Gentle touch nerves, called c-tactile afferents (CTs), work in similar ways to pain detecting nerves, but with an opposite function. CTs relay events that are neither threatening nor tissue-damaging. Instead, these events are pleasing and rewarding.
"The evolutionary significance of such a system for a social species is yet to be fully determined," said Francis McGlone, PhD, of Liverpool John Moores University in England. "But recent research is finding that people on the autistic spectrum do not process emotional touch normally, leading us to hypothesize that a failure of the CT system during neurodevelopment may impact adversely on the functioning of the social brain and the sense of self."
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Autistic individuals can be distressed by the light touch of some fabrics. Activist and assistant professor of animal sciences at Colorado State University, Dr. Temple Grandin has written extensively about her life and experiences as a person with autism. She has suggested that her lack of empathy in social situations may be partially due to a lack of "comforting tactile input." Deficits of nurturing touch during early life, according to McGlone, may have negative effects on a range of behaviors and psychological states later in life.
The scientists say that further research on CTs is necessary to develop new therapies for autistic patients and others who lacked adequate nurturing touch early in life. Researchers might also gain insights for new treatments of pain by understanding how the nerves that relay rewarding sensations interact with those that relay pain.
A healthy, functioning emotional touch system is as important to well-being and survival as having a system that protects us from harm, according to McGlone.
"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," he concluded.