Soft touch gone awry in autism

Nerves in the skin that respond to gentle touch may go awry in disorders such as autism say researchers in Liverpool. Using a range of scientific techniques, researchers from Liverpool John Moores University are beginning to characterise these nerves and to describe to role they play in our lives. They believe that the nerves that respond to gentle touch called c-tactile afferents (CTs) are similar to those that detect pain but 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,” said Francis McGlone, first author of the paper published in Neuron. “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.” The lightest touch of clothing can cause distress for some individuals with autism, and McGlone notes that deficits in nurturing touch delay in early life – a gentle caress for example – could have negative effects on a range of behaviours and psychological states later in life. 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 protects 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 care or parent due to the economic pressures of modern living, it is becoming more important to recognise just how vital emotional touch is to humankind.” Further research on CTs could help investigators develop therapies for autistic patients and individuals who lacked adequate nurturing touch as children. A better understanding of how nerves that relay rewarding sensations interact with those that signal pain could offer new insight into new treatments for certain types of pain. Discriminative and Affective Touch: Sensing and Feeling