The default neural network (RND)

It is common to find oneself in the middle of a self-absorbed situation, daydreaming or, as they say in Spain, "thinking about shrews". Even in situations where there is plenty of light and movement around us can be detected, we have an amazing ability to think about nothing, ignore what is happening in the immediate environment and simply let ourselves be carried away by a pleasant sensation of having nowhere to direct our attention.

These episodes where we get lost in a stream of confusing and difficult feelings and thoughts delimiting do not occur by chance, since they have a neural basis in the normal functioning of our brain. The set of parts of the brain involved in this activity is called Neural Network by Default (RND), and the research carried out to better understand this structure serves to better understand how we think and feel.

A not so random noise

For many years it has been believed that the brain is an organ whose level of electrical activity basically depends on whether it is working to solve cognitive tasks or not. From this point of view, for example, the neural machinery in our head would start to really perform only at the moment we try to remember something to answer an exam question, solve a puzzle, observe a person closely or, for example, follow instructions to assemble a piece of furniture.

Daydreaming: the brain keeps working

However, When we daydream, the neurons in our brain continue to send electrical impulses in a massive way.. Before it was believed that this neural activity in areas not related to bodily activities that keep us alive was simple noise, it is that is, electrical signals thrown at random and emitted in an uncoordinated manner, such as snow appearing on a television screen poorly connected to your antenna.

Today, instead, we know that this electrical activity does show well-defined patterns and there is coordination in it, which shows that these neurons continue to respond to a function in the middle of the self-absorption stage. We also know that surprisingly, when we start to wander and stop paying attention to our surroundings, our brain consumes almost the same energy as when we perform complex cognitive tasks that we have to perform consciously: only 5% less.

In some way, our brain is designed so that we can daydream, and it is likely that this activity has one or more specific uses.

The dark energy of the brain

We know that brain activity continues to exist even when we stop paying attention to stimuli from the external world. However... What is all this activity for? What kind of neural processes are taking all those resources that are not destined to solve issues related to the environment?

At the moment, little is known about this question, and this is what has led some researchers to talk about the "dark energy of the brain", a type of trigger that is known to be there but whose function is unknown.

Where does the default neural network take place?

However, what we do know about this neural activity is that it is associated with very specific areas of the brain. This set of regions involved in these mysterious activation patterns has been baptized with the name of Neural Network by Default, Default Mode Network in English.

In other words, these recent research shows that the human brain is prepared so that its level of activity does not decrease much when our thoughts fold back on ourselves. In the moments in which we remain absorbed we enter a "default mode" that we are just beginning to understand, and the default neural network is thus the tissue of nerve cells that allow this happens.

Exploring the default neural network

The default neural network is divided into three zones: the medial area of ​​the temporal, parietal and prefrontal lobes. These regions are activated in one way or another depending on whether we are carrying out tasks that require sustained focused attention on changing elements of our physical environment. Specifically, and although it may seem counterintuitive, the default neural network is activated when we start to ramble and We enter a state of self-absorption, and it shuts down when tasks related to the external world require our attention.

Regarding the psychological aspect of what the coordination of neurons of the neural network entails by default, we know that during moments of reverie our thoughts, although imprecise and difficult to express verbally (partly because of the little attention loans), revolve around the idea of ​​"me" and imaginary situations that could happen in the future, more than revisions of past experiences. This leads us to believe that the function of the default mode may be related to the anticipation of events and our reaction to them, although this hypothesis has yet to be tested.

What does the default neural network tell us about daydreaming?

What we know about the default neural network leads us to conclude that the nature of this kind of "mental wandering", or mind-wandering, is different from how we believed: it is not an activity that involves the blackout of large areas of the brain and a decrease in the coordinated activity of our neurons, but rather is still linked to a systematic and determined functioning of brain areas. In other words, when we daydream our brain is not deactivated, but enters a different state of activation.

Our minds are not designed to "go blank"

Thus, it is difficult to assess to what extent our mind is blank if when this happens our brain enters a kind of activation that consumes almost as much energy as thought focused on external stimuli.

Investigating about the functioning of the default neural network can help us to better understand what we are talking about when we refer to the activity of "dreaming awake "and brings us closer to the possibility of revealing to which useful aspects of brain functioning this set of neurons is associated and by what logic this type of activation.