Why does your brain look like a giant walnut, how does it fit in enough wiring to stretch four times around the equator and why can a magnet on your head stop you in mid-sentence? In the first of this year's Christmas Lectures, Professor Bruce Hood gets inside your head to explore how your 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.