Claudia Hammond finds out how neuroscientists are understanding musical hallucinations by looking at the brains of those who experience them. Tim Griffiths and Vicky Williamson talk about their research into musical imagery and what it reveals about the workings of the brain and why musical hallucinations are more common in people with hearing loss. Nathan Filer and Matt Haig join Claudia to talk about their novels: The Shock of the Fall and The Humans and why they chose to write about mental health. Dr Catherine Loveday discusses recent research into why some people are hard-wired to be better navigators than others and why drawing could improve learning.