Touch

The sense by which certain characteristics of objects, such as their size, shape, temperature, and surface texture, can be ascertained by physical contact. The skin has many types of touch receptors, including Merkel’s discs and Meissner’s corpuscles to detect light touch, and Pacinian corpuscles to sense deep pressure and vibration. Signals from these receptors pass, via sensory nerves, to the spinal cord, from there to the thalamus in the brain, and on to the sensory cortex, where touch sensations are perceived and interpreted. The various parts of the body differ in their sensitivity to painful stimuli and in touch discrimination. For example, the cornea is several hundred times more sensitive to painful stimuli than the soles of the feet. (See also sensation.)