After the earthquake: why the brain gives phantom quakes
Some people caught up in the earthquakes in Italy will experience aftershocks that are all in the mind, says Daniel Glaser
People left homeless by the earthquake near Norcia in central Italy. Photograph: Crocchioni/EPA
Earthquakes in Italy have devastated ancient towns and left thousands in temporary accommodation. Luckily no deaths were reported after the country's strongest quake in decades struck last Sunday, but the psychological effects for those who were there could continue for some time.
Aside from aftershocks, anyone caught up in the disaster may also experience the uncanny sensation of 'phantom quakes', where it feels as if the earth is shaking when in fact it is perfectly still. This happens for the same reason as 'sea legs' - the swaying feeling you sometimes get when you walk on dry land after time on a boat.
The brain's balance system keeps us upright by analysing signals sent by the ears, eyes, legs and feet and uses this data to predict which way is up. Normally, if you make an unpredictable movement, like stepping on something that's lower than you think, your motor cortex quickly adapts as it knows what the real world is like. But experiencing an earthquake temporarily shakes these assumptions, so a misstep can possibly trigger a mini 'earthquake' that is all in your mind.
Dr Daniel Glaser is director of Science Gallery at King's College London
--
__._,_.___
No comments:
Post a Comment