QotW - How long could we survive without a head?

30 October 2017

Question

Time now for Question of the Week, and this week Michael Wheeler’s been getting his head around this creepy Halloween head scratcher...

In the 1940s, there was a chicken that survived 18 months without a head. How long could a human survive without a head?

Answer

Michael - This story seems unbelievable but it is, in fact, true. No ‘fowl’ play involved.

So what does this mean for us? We asked our listeners and Alan thinks that it could be possible, in principle, to keep the body alive with a ventilator and supply of nutrients.

But what does our expert think? We asked Dr Shiva Shanu, Senior Research Associate in Clinical Neuroscience at the University of Cambridge and Lecturer at the University of Kent.

Shiva - The long story is that while some facial reflexes might survive for a few seconds or even minutes, consciousness almost certainly will disappear very quickly, at most within a second or two.

The thing is, immediately following the separation of the head from the body, there will be a sudden drop in blood pressure inside the head. And, as a result, neurons in the brain would very quickly lose the oxygen and the energy they need to keep up their normal pattern of electrical activity, and that’s the activity that sustains cognition and awareness. Hence, without this vital supply, consciousness couldn’t last.

However there is scientific evidence from non-human animals that brain activity might persist for a bit longer than a few seconds after losing your head. But that activity is highly likely to be related to basic reflexes if anything, but not to awareness.

Michael - So your average human wouldn’t survive for more than a second or two. But what makes chickens so special?

Shiva - Regarding the curious case of  Miracle Mike, the headless chicken, really the only thing that I would comment on there is the remarkable difference in architecture between the bird brain and our brain. Party because of this, when Mike lost his head, it didn’t really produce the same sort of complete disconnection that we would experience if our head was severed at the neck.

A considerable part of Mike’s brain might well have been preserved, certainly, the bits that control fundamental biological processes like respiration, digestion, etc. That, and the fortuitous and crucial blood clot that prevented Mike from bleeding out, enabled him to survive that long. It’s still quite a unique story after all these years.

So, in summary, we wouldn’t survive very long after losing our head. Though it has been noted that a momentary sensation of pain will precede the loss of awareness and certain death.

Michael - The science of decapitation. You probably thought we’d be too ‘chicken’ to go there! But there it is.

Next week we’ll be sparking some debate with this shocking question from Elizabeth:

Hello Naked Scientists; greetings from South Africa. I was driving on the highway while it was raining and thundering overhead. I remember that someone said a car is a safe place to be in a thunderstorm as it acts as a Faraday cage and the lightening will go around it. Is this true or would the engine shutdown which could cause a huge accident?

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