“Beginning in the 1940s, Canadian brain surgeon Wilder Penfield mapped the brain’s motor cortex — the area that controls the movement of your body’s muscles. He did this by applying mild electric currents to the exposed brains of patients while they were in surgery. Now you can relive his exploration of the brain. In the following feature we give you an electric probe and an exposed brain. All you need to do is shock and observe.” In addition to this somewhat dated shockwave, the site also offers an infographic (bottom of the page) illustrating how much of the brain’s motor cortex is devoted to controlling specific body parts. Seems like a good candidate for inclusion in the next Tufte book.