Unlike the other four senses, touch is ubiquitous, involving sensory terminals dispersed over the outside and on the inside of the body. This system encodes a variety of sensations in addition to touch, such as pain, vibration, pressure, stretch, itch, texture, and temperature. The system is sensitive to certain chemical states like painful tissue acidity, the result of inflammation or infection. Touch also underlies the brain’s sense of where parts of the body are positioned at any given moment, crucial to motor control. Research reported in April 2001 focuses on an ion channel in mammals that appears to mediate the sense of touch. It is the first molecule identified in the macromolecular complex that converts touch stimuli to a neural signal. It belongs to a new family of ion channels, dubbed brain sodium channels, or BNaCs, which may be mechanically gated.