This brain that we ask too much of
Our brain can be said to operate in two primary modes, two major mental states, each of which corresponds to a network: the “executive network” and the “default network” (DN), also called the “default mode network” (DMN). If we speak of networks — not centres as was the case before Marcus Raichle’s contribution to the discovery of how the default network works in 2001 — it is because they are links of neurons involving brain regions that may be far apart.
The executive network, which is based in the prefrontal cortex, manages our high-level cognitive functions, including our attentional mechanisms, working memory, and ability to communicate, plan and strategize. It is this network, which is not very active, almost inactive when we are at rest, that is set in motion when we engage in a specific cognitive activity. In conjunction with this network is another neural network called the “error detection system,” which involves three brain regions — the anterior cingulate cortex, the amygdala and the insula. This system plays an essential role, among other things, in the processing of emotions, which are inseparable from our cognitive processes (see The importance of emotions in learning).
Having to juggle with several objectives that are supposed to be equally pressing puts sand in the gears of our cognitive machine.
In everyday life, all these brain regions deploy energy to help us achieve our goals. Our working memory and our error detection system are particularly solicited. The latter must continuously be on the lookout to warn us when our strategies seem to be diverging from our goals. In addition, having to juggle with several objectives that are supposed to be equally pressing puts sand in the gears of our cognitive machine. As cognitive neuroscientist and attention specialist Jean-Philippe Lachaux explains in “Le cerveau en vacances” from Cerveau & Psycho: “Our mental life is then complicated by the simultaneous maintenance in memory of multiple goals that compete for our cognitive resources. […] This stacking up of objectives with no clear hierarchy, all apparently important and potentially urgent, clogs our working memory (a large amount of information must be mentally accessible at all times, if only to remind us of what we have to do), gives the disagreeable feeling of being at the mercy of an error or a delay and places us in a situation of cognitive conflict, hence the feeling of mental fatigue.”
Being absorbed in a task without our attention being “divided” or our mind constantly escaping is not in itself a source of fatigue, on the contrary.
This feeling of mental fatigue may not be due to a lack of the brain’s primary fuel, sugar (glucose) — a refuted hypothesis — but at least in part to a decline in various neurotransmitters that haven’t had time to be synthesized again. You will probably not be surprised to learn that the overabundance of information and the constant numerical solicitation that characterize our era hamper our brain’s prioritization processing of objectives. “We can do everything at the same time: without even moving from my chair, I can buy a train ticket, chat with all my colleagues, watch countless videos, learn the guitar… As a result, it is much more difficult to establish a hierarchy at any given moment between all the things we can do, and this naturally leads to a dispersal of attention,” says Jean-Philippe Lachaux, this time in an interview with the enlightening title Well concentrated, you are less tired and less stressed (Bien concentré, on est moins fatigué et moins stressé!). The fact that being absorbed in a task without our attention being “divided” or our mind constantly escaping is not in itself a source of fatigue, on the contrary. “By being totally involved in what we are doing, without trying to do several things at once, we also reduce conflicts in the brain: there is no longer any doubt about what is important and what is not. […] There is no negative interference between brain regions involved in contradictory cognitive processes. The result is a sense of relief: what is commonly referred to as mental overload is reduced,” says Lachaux.
This state of involvement can be linked to the state of flow, which is “a psychological state of deep well-being, intense concentration and motivation, which is achieved when an activity constitutes a challenge perceived as equal to or slightly superior to one’s abilities.” In his book Flow: The Psychology of Optimal Experience (1990), the Hungarian psychologist Mihaly Csikszentmihalyi, to whom we owe this concept, expresses the idea that well-being and happiness are not constant, but that we can achieve better results by learning to reach the flow zone more often. Rather than feeling passive and under the influence of external factors, the state of flow allows us to control the content of our consciousness —control not to be confused with excessive control which, on the contrary, would be detrimental to the emergence of this “optimal experience” (see 8 Key Elements of Learner Engagement).
Let’s return to our hectic daily life, where the obligation to achieve results is less conducive to a state of flow than to stress and anxiety, two states that can seriously hinder our momentum if they become chronic. “Faced with a stressful element, the body produces stress hormones that are used for fighting or fleeing. These hormones travel to the brain and have a marked preference for certain regions involved in learning, memory and emotion regulation,” explains Sonia Lupien, neuroscientist and director of the Centre for Studies on Human Stress. Studying the mechanism of stress and its effect on performance and memory for more than 20 years, the researcher has discovered that our selective attention is one of the first mechanisms to be affected by stress. “When a disruptive event occurs, an individual’s full attention is captured by that event. […] With limited attentional resources, an individual cannot process both information about the disruptive event (here, the stressor) and items related to the memory task,” report Lupien and his colleague Françoise Maheu in their 2003 study.
When fighting or fleeing doesn’t seem possible, it’s a feeling of powerlessness that awaits us.
“Animal research has clearly shown that stress and anxiety can completely block the learning process,” recalls neuroscientist and learning specialist Stanislas Dehaene. That’s saying a lot, given the importance of this faculty in human beings, regardless of age. Let’s add, as Dominique Servant, psychiatrist and psychotherapist specialized in stress and anxiety, points out, that fatigue is one of the “first signs that mark a difficulty in adapting (negative consequences of stress), when the body can no longer recharge the batteries.” To fight stress on a daily basis, Sonia Lupien recommends cognitive micro-breaks, the time to let our stress hormones decrease. “If I have difficulty concentrating, I get up and go for a walk with the dog, for example. Cognitive micro-breaks are essential, especially in these times of stress,” says Lupien.
When fighting or fleeing doesn’t seem possible, it’s a feeling of powerlessness that awaits us. In his video How to rest and get a job? (Comment se reposer et décrocher du boulot?), neuropsychologist Guillaume Dulude warns us that ignoring the way the brain rests, the “rules” that must be followed for it to do so, puts us at greater risk of feeling this state. “When we overuse the same systems and therefore don’t get rest, we experience helplessness,” he says, adding that this feeling is one of the greatest generators of negative emotions in humans. “When a human feels in advance that he does not have the resources to face a challenge, or when he feels that facing that wall, he will not be able to reach the goal, these are ideal conditions of helplessness,” stresses the doctor of neuropsychology.
Biochemically, Dulude points out, this high sense of helplessness affects not only our levels of cortisol, the “stress hormone,” but also our levels of serotonin, one of the neurotransmitters that he points out is among the most important for the activation of positive emotions, including being able to make choices, being alert, performing tasks and moving from one task to another effectively, and taking a break. While high feelings of helplessness are associated with low serotonin levels, the neuropsychologist points out that “you need a minimal pool (level) of serotonin in the brain, mainly in the frontal and prefrontal lobe, [i.e.] in the executive centre […].”
Spotlight on the default network
Our executive network is, therefore, day after day, highly solicited. Now, we all know that our controlled and voluntary thoughts, which are under the guidance of this network, very frequently give way to what can be described as spontaneous thoughts, daydreams or mental vagrancy. A 2010 Harvard University study showed that we spend almost half (46.9%) of our days “in the moon,” a state in which our brain is in the default network mode. This is not the only functional network in the resting state, but it is the one that consumes the most energy and has the strongest and most constant connections. Since its discovery in the early 2000s, it has generated considerable interest among researchers, which has helped to unravel some of its mysteries.
We spend almost half (46.9%) of our days “in the moon,” a state in which our brain is in the default network mode.
We now know that many of the brain regions through which this network passes are also part of the executive network and, surprisingly, these areas become more active when we are in the default network mode than when we are focused on a specific cognitive activity. As Marcus Raichle, neurologist and professor of radiology at Washington University School of Medicine (Saint Louis, Missouri) summarizes: “We conventionally tend to think that when we are not busy doing such things, our brain is “free,” or more passive, and we automatically think that we primarily use the brain to solve difficult tasks, or control goal-directed activities.” The eminent neurologist and his team found the opposite to be true in their 2001 study, where participants were asked to perform specific cognitive tasks using brain imaging. “We were really surprised that after the demanding tasks were completed, activity in these areas of the cortex increased again. The brain seemed to return to a default level of activity that is there in the absence of a specific, continuous, external task. So, we decided to take a closer look. We now understand it as a special network in the brain that, paradoxically, is more active when we are not involved in a goal-directed task,” says Raichle.
The mental processes associated with the default network are rather introspective in nature. They include not only the ability to reflect on oneself, recall memories and make future projections but also the ability to decode the mental states, emotions and behaviours of others — what is called social cognition. In short, it is indeed “there” that we find ourselves when we are in the moon… and if we struggle most of the time to bring our attention back to order, it is because our attentional resources are at the heart of an incessant struggle between our executive network and our default network, as demonstrated in 2011 by a team of Inserm researchers led by Jean-Philippe Lachaux and Karim Jerbi. Measuring for the first time the electrical activity of neurons in the default network, their study revealed that as soon as our attention is focused on an external object, the default network disconnects and that it only takes a tenth of a second to reconnect or disconnect again. “In my lab in Lyon, we showed, using a very simple visual attention task, that the activity of the default network returns to its normal level as soon as the task is completed, in a fraction of a second,” says Lachaux. “The brain, therefore, seems to fill all the “empty” moments without explicit instructions with the default network, according to what seems to be a principle of communicating vessels,” he adds. It is a third large neural network, the neural monitoring network, which allows this switchover between the default network and the executive network.
Different hypotheses have been put forward to explain the basis of this process of back and forth between the two networks. For some researchers, it could be a power-saving strategy comparable to putting a computer to sleep, while for others it could be a way to keep certain neural connections minimally activated to prevent them from disappearing. Still, other researchers believe that this mechanism could help us better cope with any eventuality. “It’s a dynamic and evolutionary process that keeps going. In our opinion, the brain is constantly trying to restore a balance between the inner and outer worlds, which implies that it allows us to avoid unpleasant surprises by making hypotheses about the future,” neurologist Andreas Kleinschmidt says in Le Monde.
Fostering balance down to the neuronal level
The 2011 study by the Inserm team seems to indicate that activating the default network would give the executive network a break, allowing it to be more efficient. That said, this activation does not necessarily lead to a feeling of relaxation and well-being. In fact, the Harvard study mentioned earlier reported that the more we are in the moon, the more unhappy we tend to be, and that, on the contrary, the more we are invested in an activity, whatever it may be, the more satisfied we feel. It should be noted that in this study, the researchers were able to specify that the mental vagrancy of their subjects was generally the cause, and not the consequence, of their unhappiness.
It is not uncommon for healthy persons to have a default network that works too much, making them go from daydreaming to rumination, putting them at greater risk of suffering from attention disorders, anxiety and depression.
It has been shown that abnormal activity of the default network can, in the most serious cases, be a sign of neurodegenerative or neuropsychiatric disease. However, it is not uncommon for healthy persons to have a default network that works too much, making them go from daydreaming to rumination, putting them at greater risk of suffering from attention disorders, anxiety and depression. Jean-Philippe Lachaux also encourages us to be vigilant in this regard, while on vacation: “It is not necessarily restful to sit on a beach or to face a mountain landscape, if you spend all your time lost in past or future scenarios. […] By loosening the grip on our schedule and on our mental activity, vacations leave more time for those moments of emptiness without a precise objective. This can be pleasant, but be careful not to fall into the trap of rumination.”
The positive point is that it is, for most of us, possible to protect our default network from overheating. Indeed, studies have shown that meditation, especially mindfulness meditation — that form of meditation where we focus on our breathing and inner state — can decrease activity in the default network (Garrison and al., 2015), strengthen connections (Zeidan and al., 2010) as well as promote executive function and sustained attention (Valentine and Sweet, 2007; Zeidan and al., 2010). And the benefits may be felt after only a few weeks or even days of practice. In addition to making meditation a part of our lifestyle, there are certain criteria that we should consider when choosing an activity during our breaks or vacations. “Having only one thing to do, within a reasonable period and without an excessive focus on our performance,” is what Jean-Philippe Lachaux recommends. He suggests opting for a type of mental activity that he calls “intermediate,” such as sudoku, crossword puzzles, simple walks, colouring and other creative hobbies. “Of course, the mind sometimes escapes into thoughts, but it is regularly brought back to its main task. Vacations are an opportunity to do one thing at a time, with no obligation to achieve results, and perhaps that’s their secret. A brain at rest is not so much an inactive brain (that’s impossible), as a brain that is totally involved in its current activity, without any other perspective,” adds Lachaux.
Our moments of rest should also allow us to indulge in deeper and more constructive reflections on ourselves.
In addition to trying to calm down one’s default network activity and let the executive network renew its exhausted neurotransmitters, it would also be beneficial to cultivate a healthy escape from the mind. “It’s becoming increasingly clear that this undirected thinking is crucial to consolidating one’s identity and giving meaning to one’s life. Unfortunately, in our daily routine, we are often too busy doing one task after another, which prevents us from indulging in what I call constructive internal reflection,” says neuroscientist and psychologist Mary Helen Immordino-Yang (2012) in the article “The brain also needs a vacation” (“Le cerveau aussi a besoin de vacances“) from Québec Science. According to her, the brain’s flexibility to switch from executive mode to default mode and vice versa and the robustness of the default network connections are linked, in particular, to a greater sense of well-being.
Ideally, therefore, our moments of rest should not only be used to “change our mind” or “change the discomfort;” they should also allow us to indulge in deeper and more constructive reflections on ourselves. In this regard, a connection can be made between this type of introspection, the meditative state, and metacognition, since all of these states occur in a calmer attentional mode that has moved beyond the thought bouncing and allows us to become aware of and act upon our mental processes.
The right game plan for a full recovery
At the beginning of this article, we “complained” about the fact that rest is still not given the importance it deserves as a healthy lifestyle habit. However, the world of sports is an exception in this regard and has been for a long time. In fact, any good training program includes recovery periods — or tapers, as they are called in the jargon — which are carefully planned by the coach since they play a significant role in an athlete’s fitness and performance. “Recovery is very well known in sport; it’s not something to be taken lightly. It’s part of the training. It’s not “nothing”. Rest “is” strategic,” insists Guillaume Dulude in his video capsule How to rest (really!) (Comment se reposer (réellement!)), he who, in addition to being a doctor in neuropsychology, is a former top-level swimmer. He adds that “athletes who are not able to rest, even if they do less sport, tend not to be able to recover to their full potential before a competition.”
While doing less doesn’t necessarily lead to recovery, trying very hard to do nothing to replenish our energy reserves can have the opposite effect. “Effective rest comes from a natural recovery process, so it doesn’t come with the action or willingness to rest. Rest comes with the deactivation of a system, whether it be neuro-anatomical, muscular or cellular,” says the neuropsychologist. This is all the more obvious when it comes to our mental resources. If you’ve ever had insomnia, you know that paying full attention to trying to fall into the arms of Morpheus is a great way to stay awake. The same is true for the beginning meditator, who is trying too hard to chase away his thoughts and instead finds himself more and more invaded by them.
With practice, all hopes are high, since the brain, at any age, has the ability to change itself as a result of new learning
“It’s not about blocking thoughts and clearing your mind… it doesn’t work,” says Buddhist monk Matthieu Ricard, who has been practising meditation for decades and is collaborating in neuroscience research on the impact of meditation on the brain and health. In the case of meditation practice, the right posture, according to him, is to “let thoughts pass like birds crossing the sky. Easy to say, much less to do! But with practice, all hopes are high, since the brain, at any age, has the ability to change itself as a result of new learning; a property called “neuroplasticity” which translates into the creation of new neuronal connections.
Jean-Philippe Lachaux expressed earlier that a brain at rest is “a brain totally involved in its activity of the moment.” To this, we should add, according to Guillaume Dulude — for a brain to really recover — that this activity must take it out of its habits and be planned. “In a strategy of rest, of vacation, we must “strategically” make sure that we don’t use the same cognitive structures, the same reflexes, the same thought systems, the same habits that we normally use when we work, when we expend energy,” explains Dulude. For example, a person who works in caregiving and whose listening and empathy mechanisms are very much in demand will have to turn to an activity that doesn’t demand or it demands less of these mechanisms, such as a sports activity, in order to recharge his/her batteries.
Without a conscious and planned effort on our part to get out of our habits, the brain tends to reproduce the behaviours it knows well and which have earned it a reward
If the neuropsychologist insists on the importance of a strategic approach, it is because, without a conscious and planned effort on our part to get out of our habits, the brain tends to reproduce the behaviours it knows well and which have earned it a reward, namely reinforcement in the form of dopaminergic discharge. “It’s not that simple, because the brain likes it, it’s used to getting its dopamine in a certain way, and often when we officially go on vacation, we feel like doing the same things we do when we’re not on vacation,” says Guillaume Dulude. Remember that dopamine, which acts as a neurotransmitter, is sometimes called the “happiness hormone”. When you’re trying to reach a long-term goal for which you don’t get immediate satisfaction, your body at least knows that it will get an intense dopamine boost as you reach it.
And beware! Going for a drink, eating out or going to the movies does not work, since these activities are passive, warns the neuropsychologist, specifying in his capsule Rest and diversification of interests (Le repos et la diversification des intérêts) that this is also one of the reasons why the activities we often prefer on vacation are not those that provide the most effective rest. “Everything that is passive or external does not work. I’m not saying that it shouldn’t; I’m just saying that the brain will not relax in the same way, because it’s too easy to “consume.” So, everything that is consumption, that is, external reinforcement, everything that is psychotropic, will give a superficial rest in the short term, but will not recharge us. There won’t have been enough depth in the fact that the brain has deactivated itself in a task,” he says. Therefore, we have to opt for activities that require real involvement on our part.
Let us return to the concept of the flow state to clarify that while this state can be achieved by mobilizing certain skills or abilities, it is not limited to one type of activity. Cooking, reading or playing a musical instrument are all ways that can lead us there, according to Mihaly Csikszentmihalyi, even if he perceives “extremely strong similarities” between flow and a particular activity: Yoga. “In fact, it makes sense to think of Yoga as a very thoroughly planned flow activity. Both try to achieve a joyous, self-forgetful involvement through concentration, which in turn is made possible by a discipline of the body,” he explains in his seminal work, Flow: The Psychology of Optimal Experience (1990).
In short, helping our brain to “recharge” paradoxically requires an effort; an effort that can represent a challenge for those who tend to invest themselves in a single activity… which is often, moreover, their professional activity. This leads Guillaume Dulude to recommend that, as part of an overall strategic approach to rest and healthy living, we also diversify our interests: “For me, this is a central theme. People who, for different reasons, have invested in few areas in their lives, who are extremely good at something, but who have little diversification, so they can give a lot of energy in one area, find themselves in positions where if the battery is “burnt out” it takes a very long time before it can be recharged. We see a lot of them in clinical consultation.”
For those who are reluctant to go outside their comfort zone to get some rest, Dulude suggests going gradually, the best strategy being to explore activities that may have tempted us in the past but that we haven’t yet had the chance to try; to see it as a gift, an opportunity to try something new. “The brain loves it: novelty and learning are the best resourcing strategy there is,” concludes Guillaume Dulude.
Rest is essential to our overall well-being, both in the short and longer-term. By approaching our breaks and vacations strategically, we not only give ourselves every opportunity to take a break but also to fully recharge our batteries. As you can see, without a planned approach to bring your brain out of its habits, it, which hates emptiness, is likely to do as it pleases and to lead you down steep paths, to say the least. The choice of activities is up to you, and that these activities will not only help you to “unplug,” but also to get to know yourself better and, who knows, to develop new passions!