We've usually thought that people in comas or 'vegetative' states are completely cut off from the world. But groundbreaking work shows that as much as 20 per cent of patients whose brains were considered non-responsive, turn out to be vibrantly alive, existing in a sort of twilight zone. Neuroscientist Adrian Owen guides Paul Kennedy into that "gray" zone, in conversation and in a public talk. *This episode originally aired March 12, 2018.

Traditionally, patients have been judged as non-responsive based on demonstrated behaviour, on whether they can twitch a finger or move a hand or similar. But that needs a physical response. What happens if the patient's brain is conscious and aware of what's going on, but simply can't will the body to move?

Over two decades, Dr. Owen and his team have used advanced neuroimaging technologies to scan patients' brains while asking them to imagine performing certain tasks.

Imagining playing tennis lights up specific parts of the brain. Imagining walking through the patient's home lights up other distinct parts of the brain. Using these for simple yes or no questions, neuroscientists can communicate with some patients, learning how aware they are of their surroundings, or even simply asking them whether they are in pain.

In his book, Into The Gray Zone, Dr. Owen describes some of the key patients and moments from his research. The stories of Kate, Kevin, Debbie, Carole, Scott, Juan, and many others, are a story of science and of humanity.

He tells Paul Kennedy, "It's a book about what it means to be human and about the relationship between brain, that three pound lump of grey and white matter that we have in our heads, and mind, the experiences that we have every day, the things that truly make us who we are and what we are as human beings."

Adrian Owen is the Canada Excellence Research Chair in Cognitive Neuroscience and Imaging at Western University, in London, Ontario, and chief scientific officer at Cambridge Brain Sciences. His book, Into the Gray Zone, A Neuroscientist Explores the Border Between Life and Death, is published by Scribner, 2017.

Adrian Owen is a neuroscientist and author. (Scribner/Paul Mayne)

Intothegrayzone.com has more about the book, plus videos featuring some of the key patients, and documentaries about the discoveries.

For more information about the work of Adrian Owen and his team, visit The Owen Lab website.

Adrian Owen has several videos on YouTube about consciousness and even how humour helps us understand a vegetative state.

**This episode was produced by Dave Redel.