The Default Network and Stress Reduction

The brain accounts for only 2% of total body weight and yet consumes 20% of the calories we ingest. It’s a gas guzzling truck which, when put in neural, has a higher energy consumption.

When not focused on a task, the brain ‘rests’ in a neural state which is, in fact, more active when compared to performing a chore or activity. From fMRI studies, neurologists have found that a large area of the brain becomes active when seemingly at rest and when we focus on a task the vast majority of this “Default Network” shuts down.
At first the default network was thought to be associated with daydreaming but it’s more than that.

A large component of the default network is the coordination between the prefrontal cortex and the hippocampus, the former is known to be associated with a self-centred, egotistical evaluation of information (i.e. how am I going to be affected by this? How can I benefit? and so forth), whilst the latter is associated with memory recall. In other words, the default network seems to be a semi-conscious and underlying process of active assessment of information from past experiences and relating it to how we will personally be impacted.

Volunteers with a highly active default network are found to have a hard job focusing and are plagued with wandering thoughts and thus, less resilience and higher degree of stress.
Further studies show that default network activity is found to be significantly higher in non-meditators when compared to those who regularly meditate. In other words, regular mediation seems to provide the ability to prevent mental distraction from daydreaming and wandering thoughts via reduced activity throughout the default network.  
This is now thought to be one of the reason why mediation helps enhance and maintain cognitive function through repair and growth because it allows the mind to truly rest. It’s also thought to be associated with reduced stress because meditators have an increased ability to control their default network and reduce mental distractions allowing increased clarity of thought and focus.