An indigo mantis.

Incidentally, I was re-listening to the Oliver Sacks interview about hallucinations last night and in it he has a fascinating story about how a hallucination he had about indigo made him wonder whether the color actually even existed in the world.

by Wesley Fleming

HT Scientific American

I was fascinated that one could have such perceptual changes, and also that they went with a certain feeling of significance, an almost numinous feeling. I’m strongly atheist by disposition, but nonetheless when this happened, I couldn’t help thinking, ‘That must be what the hand of God is like.’

— Oliver Sacks on the hallucination he had when he first tried marijuana. While looking at his hand, it appeared to be retreating from him, yet getting larger and larger.

“I usually get the zig-zag, but I may also see lattice patterns, like tessellations; sometimes these lattice patterns seem to cover people’s faces or a piece of paper I’m writing on. I mostly get complex geometrical patterns; I’ve never actually seen … images with a migraine, although on at least on two occasions, I’ve have had a smell — in particular a smell of hot buttered toast — with a strong sense that I was about 3 years old, being put in a high chair, and about to be given hot buttered toast, a sort of olfactory hallucination often goes along with recollection in that sort of way.

“The first time I got that I was in hospital, and I went searching for the toast. The second time I was driving on the Bronx River Parkway where there was obviously no toast to be had.”

- Oliver Sacks on the hallucinations accompanying his migraines

With any hallucinations, if you can do functional brain imagery while they’re going on, you will find that the parts of brain usually involved in seeing or hearing — in perception — have become super-active by themselves. And this is an autonomous activity; this does not happen with imagination. But hallucination, in a way, simulates perception, and the perceptual parts of the brain become active. … [Also] there’s obviously a very, very strong passionate feeling of love and loss with bereavement hallucinations, and I think intense emotion of any sort can produce a hallucination.

— Neurologist Oliver Sacks on hallucinations that accompany bereavement

Audio for Terry’s interview with Oliver Sacks is now up. Enjoy! (Also, feel free to download any of the mp3’s from our recent broadcasts. They all live here…copy the link for the sound file and delete everything after the letters mp3.)

Neurologist Oliver Sacks on his experimentation with amphetamines during the 1960s: “I’m glad to have survived that and this was more than 40 years ago. But I did have a period in which for about two weeks when I wasn’t actually taking anything when something seemed to happen to my sensorium. That’s to say, I became acutely sensitive to smells. I have a reasonable sense of smell but for two weeks, I could recognize everyone I knew by smell. I could almost find my way around New York by smell. But I also found my visually imagery — which is very poor — greatly enhanced. At that time, I was doing neuropathology, which involved cutting brains and dissecting brains. And I found that structures in the brain I could image with great vividness and then draw almost as if they had been projected by a camera lucida or something like that. This amazed me because I was always particularly bad at drawing and I’m now particularly bad again.”

I sometimes find myself just admiring the pockets of space between the different branches in a tree and walking and immersing myself in those pockets of space. It is just beautiful. It is a beautiful sensation.

— Sue Barry, a neurobiologist, had been cross-eyed since early infancy. As a result, she viewed the world in a flat plane and had no stereoscopic 3-D vision. In her mid-40s, Barry met the neurologist Oliver Sacks at a dinner party. She told him that she didn’t think she was missing much by not seeing the world in 3-D. But several years later, after experiencing several side effects from her vision problems, Barry decided to visit a developmental optometrist, who helped her relearn how to view the world stereoscopically.

'Musicophilia' Examines Music in the Mind

Oliver Sacks has been on Fresh Air twice before, once in 1987 to discuss his book The Man Who Mistook His Wife for a Hat and once in 2007, to discuss the relationship between music and the mind.

Oliver Sacks, What Hallucinations Reveal About Our Minds

(Source: ted.com)

A Neurologist's Notebook: Stereo Sue

The New Yorker took this piece by Oliver Sacks about Sue Barry for our audience. Thanks New Yorker!

Music can lift us out of depression or move us to tears- it is a remedy, a tonic, orange juice for the ear. But for many of my neurological patients, music is even more- it can provide access, even when no medication can, to movement, to speech, to life. For them, music is not a luxury, but a necessity.

— (Our guest tomorrow) Oliver Sacks (via jesileal)