Famous author and neurologist Oliver Sacks discusses what happens when visually impaired people experience lucid hallucinations.

Oliver Sacks died in 2015, but before he did, he wrote many books on neurological phenomena. You may have read his most famous work The Man Who Mistook His Wife for a Hat or have seen his fictionalised life portrayed by Robin Williams in the film Awakenings.

In this TEDTalk, Dr Sacks discusses a phenomenon known as Charles Bonnet Syndrome, proving his theory that the brain is the “most incredible thing in the universe”.

Did you know that blind people can hallucinate? Have you ever had a hallucination?