Asked by: Olivia Mack, Newick

Advertisement

That random little twitch that you sometimes get in your eyelid is an example of fasciculation. It happens when one of the lower motor neurons in your spine spontaneously fires a signal. These nerves control an entire block of muscle fibres, so they all contract at once. Because it’s benign, there hasn’t been much research into the causes, but magnesium deficiency is thought to be one factor.

Advertisement

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.

Authors

luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.

Advertisement
Advertisement

Sponsored Deals

BBC Science Focus Magazine subscription offer

Subscription offers you will love!

  • Spread the cost and pay just £3.50 per issue when you subscribe to BBC Science Focus Magazine.
  • Alternatively, lock in for longer and pay just £37.99 per year, saving 51%!
  • Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
  • FREE UK delivery.
SUBSCRIBE NOW
Advertisement