The default neural network (DNN): what happens in our brain when we daydream?

We discover the 'private life' of our brain through the RND.

It is common to catch oneself 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 an uncanny ability not to think about our own thoughts, we have a surprising ability to think of nothing, to ignore what is happening in the immediate environment and simply let ourselves be carried away by a pleasant sensation of having nowhere to go. of having nowhere to direct our attention.

These episodes in which we lose ourselves in a stream of confusing 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 the parts of the brain involved in this activity is called the Default Neural Network (DNN), and research conducted to better understand this structure serves to better understand how we think and feel.

Not so random noise

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

Daydreaming: the brain is still functioning

However, when we daydream, our neurons are still working, when we daydream, however, the neurons in our brains continue to send out massive electrical impulses.. Previously, it was believed that this neuronal activity in areas unrelated to the bodily activities that keep us alive was simple noise, i.e., electrical signals launched at random and emitted in an uncoordinated manner, like the snow that appears on the screen of a television set poorly connected to its antenna.

Today, however, we know that this electrical activity does show well-defined patterns and there is coordination in itThis shows that these neurons are still responding to a function in the midst of a self-absorbed 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.

Somehow, 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. But... What kind of neural processes are taking away all these 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 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 activation patterns has been given the name of Default Mode Network, Default Mode Network in English.

In other words, this recent research shows that the human brain is prepared the human brain is hardwired not to decrease its level of activity much when our thoughts turn inward on ourselves.. At times when we become self-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 allows 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 performing 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 begin to wander and enter a state of self-absorption, and is turned off when tasks related to the external world require our attention.

As for the psychological aspect of what is involved in the coordination of the neurons of the default neural network, we know that during moments of reverie our thoughts, although imprecise and difficult to capture verbally (in part because of the little attention we pay to them), revolve around the idea of the "dream, revolve around the idea of the "I" and imaginary situations that could happen in the future, rather than revisions of past experiences.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 sort of "mind-wandering," or mind-wanderingis different from what we thought: it is not an activity that leads to the shutdown of large areas of the brain and the decrease in the coordinated activity of our neurons, but it is still linked to a systematic functioning of the brain. is still linked to a systematic and determined functioning of encephalic areas of the brain.. In other words, when we daydream our brain does not deactivate, but enters a different state of activation.

Our mind is not designed to "go blank".

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

Research into 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 "daydreaming" and brings us closer to the possibility of revealing what useful aspects of brain functioning this set of neurons is associated with and by what logic this type of activation is guided.