Touch, Pain, and Body Position

Touch is not one sense but several working together: pressure, temperature, pain, and a sense of where your body is in space. Pain is especially useful to understand through gate control theory. Pain signals travel to the brain on relatively slow nerve fibers. Other touch signals, like pressure, travel on faster fibers. When you rub a banged elbow, those fast pressure signals reach the spinal cord first and can partially close a 'gate,' a region of spinal cord neurons that controls how much pain signal passes upward to the brain. Less signal gets through, so you genuinely feel less pain, not just a distraction from it.

The gate is not just a passive relay either; the brain itself can influence how open or closed it is, which is part of why mood, attention, and expectation change how much pain someone feels. This top-down influence also explains phantom limb pain. The brain builds and keeps a map of the body in the somatosensory cortex. When a limb is amputated, its mapped region does not disappear. That cortical territory can still fire, sometimes triggered by activity in neighboring brain regions, producing real aching or tingling sensations that seem to come from a foot or hand that is no longer there.

Body position adds two more senses. Kinesthesis uses receptors in muscles, tendons, and joints to track the position and movement of body parts, which is how you can touch your nose with your eyes shut. The vestibular sense, housed in the semicircular canals of the inner ear, tracks head movement and balance using fluid that shifts as you turn. Spin around and stop: the fluid keeps moving briefly after your body halts, which is why the room seems to keep spinning and you feel dizzy.