Sunday, June 28, 2009

When the visual cortex stops working

Today, I watched my brain turn itself inside-out. A thoroughly frightful experience, but very “interesting” (but only in the way a scientist would use the expression).

I had just disembarked from the overnight sleeper train from Tianjin, and was making my way out of the Shanghai train station towards the metro station. All of a sudden, I felt faint. After I climbed a flight of stairs up to ground level, it felt much worse. I was wobbly, and had to stop walking to hold on to a wall to prevent myself from falling over. My vision blacked out completely- I could see nothing. This lasted for about 10 seconds.

My sense of balance was failing rapidly, and even the wall was not helping me keep upright. I had to squat down and brace my head in by hands. All this while, I was worried my condition would deteriorate further causing me to keel over and pass out on the wet pavement in the rain (and lose my computer, passport and phones). This lasted for approximately 10 seconds until my sense of balance and vision returned, just barely.

I became aware of a motorcycle-taxi behind me asking if I needed a ride. I told him my address, he quoted me 15 yuan. It was a slaughter (a normal taxi would have cost 11 yuan), but I was in no shape to haggle.

I was able to get on the bike and keep myself in balance without problem, but my vision was still bedlam. In hind sight, this is not very surprising as the visual cortex is of substantial size, and visual processing is a very resource intensive task.

Below is a Photoshop recreation of my rather useless sense of vision at that time.

Normal view

Click here for large size image

WTF view

Click here for large size image

Allow me to attempt to describe what little I could see.

It was an overcast day with light drizzle, so the sky was entirely white. My field of vision had returned to normal, however, everything was in very very low resolution. In the middle of my field of vision, I could ‘see’ some detail, but everything else was a blur of white and splotches of dull colours.

When I look at buildings, I see it as if it was a pencil sketch on white paper. I could perceive some of the edges of buildings- these edges were rendered in a plain purplish colour. The rest was mostly white in colour. It appears that the perceived edges were moving with respect to my field of vision. This is consistent with findings that moving objects are easier to detect compared to stationary ones 1. Conceivably, the perception of moving objects is given a higher priority in the visual processing part of the brain.

Over the course of 5 minutes, I regained my sense of vision. I could walk and keep balance as if nothing had happened.

1 – This is important for the survival of many species. A moving object could well be a predator, and being able to detect a predator early would increase the creature’s chances of not being eaten.

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Thursday, June 18, 2009

OMG, it's Euler!

F Minus, by Tony Carrillo.

Saturday, June 13, 2009


Of late, I’ve taken to reading journal papers for leisure.

Despite the main body of most research papers being very in depth studies of very specific, these papers do provide a fair bit of enlightenment of the field of study and general fragments of knowledge.

Here are a few free resources that might light your boiler:

Project Euclid
Polish Virtual Library of Science


Thursday, June 11, 2009

Fate has dealt me a good hand.


Monday, June 08, 2009

Joke of the day

China Squeezes PC Makers
Beijing Is Set to Require Web Filter That Would Censor 'Harmful' Internet Sites

BEIJING -- China plans to require that all personal computers sold in the country as of July 1 be shipped with software that blocks access to certain Web sites, a move that could give government censors unprecedented control over how Chinese users access the Internet.

The government [...] says the effort is aimed at protecting young people from "harmful" content. The primary target is pornography, says the main developer of the software, a company that has ties to China's security ministry and military.

The government, which has told global PC makers of the requirement but has yet to announce it to the public, says the effort is aimed at protecting young people from "harmful" content. The primary target is pornography, says the main developer of the software, a company that has ties to China's security ministry and military.

The software requirement was outlined in a notice that was issued by China's Ministry of Industry and Information Technology on May 19 but that hasn't yet been publicized by state media. The notice, a copy of which was seen by The Wall Street Journal, says PC makers must ship PCs to be sold in China as of July 1 with the Green Dam software "preloaded" -- pre-installed or enclosed on a CD.

Foreign industry officials say companies have been given little time to properly test Green Dam. "The lack of transparency, the shortness of time for implementation, and the incredible scope of the requirement that is not matched anywhere around the world present tremendous challenges to the industry," said an industry official who has discussed the plans with several major PC makers.

An excerpt from "China Squeezes PC Makers", Wall Street Journal, 8 June 2009.