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

Re: To digress a step further...

[mmcirvin.livejournal.com]

The N-Ray incident is famous in the annals of Science Gone Wrong, but I hadn't actually heard of anyone trying to figure out the neurophysiology of what was going on there.

Re: To digress a step further...

[sunburn.livejournal.com]

Basically the cone/rod distribution over the retina isn't constant but, thanks to selection, has a ratio in the center of the retina, and hence your vision, that mixes color perception and magnitude perception. Around the edges, the ratio changes to favor magnitude perception, so you can detect movement in peripheral vision. One of the essentials of observing N-rays was to not quite look at them directly, and Collins or his source supposed that most likely, the same light might be perceived as brighter as it falls off-center in the eye. Innnnteresting.

Re: To digress a step further...

[mmcirvin.livejournal.com]

Amateur astronomers use that trick to see barely visible objects such as comets with the unaided eye; faint-object perception is better with slightly averted vision than it is straight on, because there are fewer rods right in the fovea.

(Also, I think it's not so much color vs. magnitude perception as it is bright vs. faint light perception. The rods are monochrome sensors, but it's the cones that actually provide the brightness information in bright light; the rods are completely oversaturated under daylight conditions and don't do anything useful. There are people with a rare condition that makes their cones completely nonfunctional; they see in complete monochrome, unlike most color-blind people, and they also have to wear dark sunglasses during the day or they can't see at all.)