Chinese spice helps unravel the mysteries of human touch

Szechuan pepper. (Image: wikimedia) - New insight into how human brains detect and perceive different types of touch, such as fluttery vibrations and steady pressures, has been revealed by UCL scientists with the help of the ancient Chinese cooking ingredient, Szechuan pepper. Humans have many different types of receptor cells in the skin that allow us to perceive different types of touch. For more than a century, scientists have puzzled over whether touch signals from each type of receptor are processed independently by the brain, or whether these different signals interact before reaching conscious perception. For the study, published in Proceedings of the Royal Society B , UCL researchers took a novel approach to this question by stimulating one type of touch receptor chemically, and another type mechanically. This bypasses the problem of different mechanical touch stimuli potentially interacting within the skin, with unknown effects on the receptors. Instead, the UCL team used hydroxy-sanshool, a bioactive compound of Szechuan pepper responsible for the characteristic tingling quality of Szechuan cuisine, to stimulate the touch receptors responsible for the sensation of fluttery vibration.