Somatosensory System: Overview
Somatosensation includes multiple senses: pain (nociception), temperature (thermoreception), touch, and the sense of our limb position in space (proprioception). Each submodality of somatosensation relies on different types of receptors embedded in the skin, muscle, and joints and involves different structures in the spinal cord and in the brain.
Pain is arguably one of the most vital senses as it signals when our body is liable to being damaged. There are many different types of receptors in the skin that signal a potentially harmful stimulus. Some receptors respond to intense mechanical deformations of the skin, others to extreme temperatures, and still others to different kinds of chemicals. Pain comprises a sensory discriminative component, which provides information about the location, duration, intensity, and quality of the pain; an affective one, which signals its unpleasantness; and a cognitive-evaluative one, which is associated with cognitive...