Am I the only one who did this? Correction: Am I the only one who spent a great deal of time doing this? (If you did, tweet about it! #phosphenediary) As far as hallucinations go, phosphenes are pretty common, and they can be induced mechanically, electrically  and even magnetically. But what’s going on here? What makes the mind conjure the geometric patterns of phosphenes or migraine auras?

Rather than try to explain it all here, I figured I’d let neurologist and author Oliver Sacks take a stab at it. Dubbed the “poet laureate of medicine” by The New York Times, Sacks is probably best well known for the movie based on his work treating the survivors of the early 20th century encephalitis lethargica epidemic, Awakenings. He is also the author of The Man Who Mistook His Wife for a Hat and Musicophilia, which both follow various case studies of people with unique neurological conditions.

Tonight at 8pm ET, in a World Science Festival* event, Sacks will be discussing his new book, Hallucinations, live with John Hockenberry. Together they’ll discuss the causes of hallucinations, their rich cultural history, and how Sacks’ experimentation with psychedelics in the 60′s led him to dedicate his life to solving the riddles of the human mind. He’ll also be taking questions at the end of the show, so bring your curiosity and tweet your questions to #askoliver. I’ve embedded the webcast above for your convenience.

It’s going to be a great show, so I hope you’ll tune in and join us.

Update: Here’s another fantastic comic about phosphenes from A Cup of Tim.

*Full Disclosure: I work for WSF