How long would a human remain conscious after being decapitated

http://www.straightdope.com/columns/read…

On an episode of "1000 Ways To Die", a physicial set out to prove that the guillotine was an inhumane form of punishment because the people would remain conscious. However, the subject respond to any stimulus, so I think it's instant. It depends on whether there's any connection between the head and rest of the body. If it's perfectly severed, I think death is instant.

I hope this information was very helpful.

Not for long. A French physician made arrangements with a person convicted and sent to the guillotine in France. After the beheading he was able to elicit a response from the prisoner's head after it was removed. This was done by having him blink in response to questions.

During the French revolution it was shown that some who's heads were severed perfectly by the guillotine could survive until blood empties out of the brain and some would die immediately. Depends on the seperation between the head and the spine.