London, April 2: Researchers have discovered why the gentle burbling of a brook, or the sound of the wind in the trees can physically change our mind and bodily systems, helping us to relax.
Playing ‘natural sounds’ affected the bodily systems that control the flight-or-fright and rest-digest autonomic nervous systems (associated with relaxation of the body), with associated effects in the resting activity of the brain, the findings published in the journal Scientific Reports showed.
“We are all familiar with the feeling of relaxation and ‘switching-off’ which comes from a walk in the countryside, and now we have evidence from the brain and the body which helps us understand this effect,” said led study author Cassandra Gould van Praag from the Brighton and Sussex Medical School (BSMS) in England.
“This has been an exciting collaboration between artists and scientists, and it has produced results which may have a real-world impact, particularly for people who are experiencing high levels of stress,” she said.
In collaboration with audio visual artist Mark Ware, the team at BSMS conducted an experiment where participants listened to sounds recorded from natural and artificial environments, while their brain activity was measured in an MRI scanner.
The autonomic nervous system activity of the participants was monitored via minute changes in heart rate.
The team found that activity in the default mode network of the brain (a collection of areas which are active when we are resting) was different depending on the sounds playing in the background.
When listening to natural sounds, the brain connectivity reflected an outward-directed focus of attention.
But when listening to artificial sounds, the brain connectivity reflected an inward-directed focus of attention similar to states observed in anxiety, post-traumatic stress disorder and depression.
There was also an increase in rest-digest nervous system activity (associated with relaxation of the body) when listening to natural compared with artificial sounds, and better performance in an external attentional monitoring task.