Why does the brain look like a giant walnut, how does it fit in enough wiring to stretch four times around the equator, and why could a magnet on the head stop someone mid-sentence? In the first of this year's Christmas Lectures, Professor Bruce Hood gets inside the human head to explore how the brain works. He measures the brain's nerve cells in action, reads someone's mind from 100 miles away, and reveals how the brain ultimately creates its own version of reality.