PARIS: Simply looking at nature or even just digital pictures of it can relieve pain, according to new research which scanned the brains of people receiving electrical shocks.

Nature`s many health benefits has been documented by decades of research. More than 40 years ago, a pioneering study showed that hospitalised patients needed fewer painkillers and recovered quicker when they looked out of a window onto green space rather than a brick wall.

`Yet until now, the underlying reasons for this effect were unclear,` said Maximilian Steininger, a neuroscientist at the University of Vienna and lead author of a study published in Nature Communications on Thursday.

The problem is that both nature and pain can be subjective. Because people like nature, it could have a placebo effect. Or what if it is not nature that reduces pain, but city life that increases it? To find out more, the researchers recorded the brain activity of 49 volunteers using functional magnetic resonance imaging (f RMI).

The subjects looked at different images while receiving a series of electric shocks some more painful than others on the back of their left hand. The first scene depicted a lake surrounded by trees blowing in the wind, while the sounds of rustling leaves and birdsong played in the background.

In the second scene, some urban elements such as buildings, benches and alleyways were added, while city noise intruded.-AFP