Some are smeared, and some are spots

[mmcirvin]

Classic hallucinations explained as normal modes of a differential equation describing propagating excitations in the visual cortex. A couple of papers on the subject are linked here.

Comments

[ex-askesis860.livejournal.com]

Given that my personal cosmology doesn't include any supernatural features, I always assumed that Deadheads, rave kids, and migraine sufferers were detecting features of their own consciousness. I never expected to see

da(x,φ,t)/dt = -a(x,φ,t) + I(x,φ,t) + ∫ dx' dφ' f(x-x',φ-φ')a(x',φ',t)

though. To me, that's cause for so much more wonder.

[mmcirvin.livejournal.com]

They also talk about eyeball-pressure images and phosphenes generated by flickering lights.

There's also the distinction between simple images like these and more elaborate images of Jesus or talking lizards or what have you, which I assume are being generated on some deeper symbolic level like dreams, rather than as waves in the visual cortex.

[pbrane.livejournal.com]

Symbolic levels, yeah... because I've done a lot of pschedelics, and still never seen fully fleshed out images of Jesu or lizards...

But lots or swirly, rose-style stained-glass images, that's for sure...

[mmcirvin.livejournal.com]

...Also, one of the things they stress in the papers is that the spiral and tunnel patterns come from the fact that the cells in the visual cortex seems to map to visual angle with something similar to a complex logarithm. That right there immediately explains why Escher hyperbolic tesselations and the paisley spirals in the Mandelbrot set have such a powerful hippie attraction: it's all conformal mapping, dude!