It is common to surprise oneself in the midst of self-absorption, daydreaming or, as they say in Spain, “thinking about shrews”. Even in situations where there is plenty of light and it is possible to detect movement around us, we have a surprising capacity to not think about anything, to ignore what is happening in our immediate surroundings and simply let ourselves be carried away by a pleasant sensation of having nowhere to turn our attention.

These episodes in which we get lost in a stream of confused and difficult to delimit sensations and thoughts do not occur by chance, as 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 the Neural Defect Network (NDN), and the research done 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 functioning to solve cognitive tasks or not. From this point of view, for example, the neural machinery in our head would only really start to work when 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 still works

However, when we daydream the neurons in our brain continue to send out electrical impulses on a massive scale . Previously it was believed that this neuronal activity of the areas not related to the body activities that keep us alive was simple noise, that is, electrical signals thrown at random and emitted in an uncoordinated manner, like snow appearing on a television screen poorly connected to its antenna.

Today, however, 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 midst of self-absorption. We also know that, surprisingly, when we start to wander and stop paying attention to our environment, our brain consumes almost the same energy as when we perform complex cognitive tasks that we have to do consciously: only 5% less .

Somehow our brain is designed to allow us to 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. Now… What kind of neural processes are taking away all those resources that are not meant to solve questions related to the environment?

At the moment, little is known about this issue, and this is what has led some researchers to talk about “dark energy in the brain”, a type of activation 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 patterns of activation has been named Neuronal Defect Mode Network ,

In other words, this recent research shows that the human brain is prepared not to decrease much its activity level when our thoughts are retracted on ourselves . When we become self-absorbed we enter a “default mode” that we are only beginning to understand, and the default neural network is thus the tissue of nerve cells that allow this to happen.

Exploring the default neural network

The default neural network is distributed in three zones: the medial zone 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 in our physical environment. Specifically, and although it may seem counter-intuitive, the default neural network is activated when we begin to wander and enter a state of self-absorption, and turns off when tasks related to the external world require our attention.

As for the psychological aspect of what the coordination of neurons in the neuronal network by default entails, we know that during moments of dreaming our thoughts, although imprecise and difficult to express verbally (partly because of the little attention we pay to them), revolve around the idea of the “I” and the imaginary situations that could happen in the future , rather 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 the practice of 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 what we thought: it is not an activity that leads to the shutdown of large areas of the brain and the decrease of the coordinated activity of our neurons, but that is still linked to a systematic and determined functioning of encephalic areas . In other words, when we daydream our brain does not deactivate itself, but enters a different state of activation.

Our mind is not designed to “blank out”

It is therefore difficult to assess the extent to which our mind is blank if when this occurs our brain enters into a kind of activation that consumes almost as much energy as thought focused on external stimuli .

Research on the functioning of the default neural network can help us to better understand what we are talking about when we refer to “daydreaming” activity and brings us closer to revealing what useful aspects of brain functioning this set of neurons is associated with and what logic guides this type of activation.