Science Of Shivering
- 20/12/07 - There are plenty of things scientists don't seem to have found the time to work out just yet - why we yawn, why there aren't any decent Christmas cracker jokes. But here's one you would have thought they'd have figured out by now - what makes us shiver. Hayley Birch reports.
It’s around this time of year, in the northern hemisphere, that the lure of a toasty warm bed becomes too great for many of us. Before we know it we’re tucking our pyjama bottoms into our socks and heading off up the stairs at nine o’clock with a hot water bottle.
And if you live in the UK, you’ll be needing your hot water bottle tonight. Temperatures look set to plummet below freezing – enough to make you shiver. But it might surprise you to learn that until this week, the scientific world didn’t quite know what causes this reaction to the cold.
Researchers at Oregon Health & Science University in the US think they’ve found the answer - by looking at shivering in rats. “We have what we call a water jacket, which is a little blanket that goes around the rat,” Shaun Morrison, neuroscientist and co-author of the study told the Null. “We can circulate cold water in that blanket and that will make the rat cold and then we can record the electrical activity in muscle.”
Morrison and his team injected chemicals to ‘turn off’ the activities of cells in different areas of rats’ brains whilst they were wearing their cold jackets. When the rodents stopped shivering, they knew they’d hit the right area, which turned out to be a region called the lateral parabrachial nucleus. Cells in this area receive cold signals and send them to another region called the preoptic area, which tells the muscles to start shaking to generate heat.
So this is how it works in rats. But is the same true for humans? There aren’t any definitive answers yet, but an Australian biologist, Robin McAllen, has developed a water jacket that works in the same way for human subjects, who are asked to endure freezing temperatures whilst they have their brains analysed in an MRI scanner. “They have looked at one area of the brain that we’ve also looked at and found that same area lit up or was active in humans during cooling.” says Morrison.
Once the two sets of data have been reconciled, perhaps scientists will finally be able to put this mystery to bed. But we’ll still be shivering in ours. Sleep tight.
Feeling chilly?
- Achoo! - Don't sneeze in your hand, use your sleeve
- It works like this - Brain freeze
- Yowzer - A man in his pants at the North Pole
- Silly - Star Letter: Global cooling
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Image: redbaron
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