This homunculus visualizes the connection between different bodyparts and areas in brain hemispheres.
Body on the left side is the motor homunculus. The bigger the body parts in this picture are, more brainpower there is dedicated to controlling them. Positions of motor areas for these body parts can be seen on the top in the right hemisphere (left side of brain control the right side of the body and vise versa). To compare different areas, you may click on different parts of the picture.
The body half on the right is sensory homunculus. It is similar to the motor homunculus except that it tell how much brain power is dedicated for sensing different bodyparts.
If you want to run the homunculus offline, you can download homunculus.jar. Should you have Java installed in your computer, you can run homunculus by double clicking the jar file you have downloaded.