Cortical homunculus (noun, “CORE-tick-uhl ho-MUN-cuh-luhs”)
The cortical homunculus is an illustration that represents how the brain senses and controls different parts of body. There is one of these maps for our movements. There’s another for our sense of touch. In the cortical homunculus, the size of a body part in the picture corresponds to the amount of the brain devoted to it. So the lips — which are very sensitive to touch and have a lot of space set aside for them in the brain — are drawn very large. The torso is not very sensitive, so it is drawn very small.
In a sentence
With toothpicks and ruler, you and your friends can draw your own homunculus and watch as representations of your body parts grow and shrink.
Follow Eureka! Lab on Twitter
(for more about Power Words, click here)
cortical (in neuroscience) Of or relating to the brain’s cortex.
cortical homunculus The visual picture of how much space each part of the body takes up in the a part of the brain known as the somatosensory cortex. It’s the area of the brain that first processes touch. It can be drawn as a series of body parts mapped onto a brain, or as a human figure with the size of each body part corresponding to its relative sensitivity.
homunculus (in science) A scale model of the human body that represents certain functions or characteristics.