The Brain is one of a four-part series, What's It All About, that explores some of the big questions of life.
In this episode we look at how the brain works and what happens when it doesn't. We hear how psychopaths are made, how meditation and mindfulness change the very structure of our brains, and how tiny mind-controlling parasites make us question the very notion of free will.
Produced by Colette Kinsella, who co-presented with science writer Seán Duke.
Broadcast on RTÉ Radio 1.