The seemingly simple act of reaching for a cup of coffee requires a lot of effort from the brain.
It has to plan a trajectory to the cup, control dozens of muscles, make adjustments based on feedback from the eyes and fingers, and maintain its focus on the goal: a tasty jolt of caffeine.
And it turns out that medical textbooks may be wrong about how all this happens. The books show a model of the brain in which the motor cortex is solely controlling movement.