Neurobiology Of Love: The Theory Of The 3 Brain Systems
Love is one of the most complex phenomena that human beings are capable of feeling. This peculiar feeling has made people wonder how and why it happens. Science has also dealt with this phenomenon, and one of the best-known researchers in this line of research is Helen Fisher a biologist and anthropologist who has spent more than 30 years trying to understand it.
To try to explain this complex feeling, Fisher focused on trying to find out the brain mechanisms that are involved in the process of falling in love and love To do this, she subjected several subjects who were madly in love to fMRI scans, to find out the areas of the brain that are activated when the subject thinks about their loved one.
“Loving” and neutral photographs
To perform the tests, Helen asked study participants to bring two photographs: one of the loved one and another that had no special meaning, that is, a neutral face Then, once the person was introduced into the brain scanner, they were first shown the photograph of the loved one on the screen for a few seconds while the scanner recorded the blood flow in different regions of the brain.
The individuals were then asked to look at a random number, and then they had to subtract it from seven by seven, and then look at the neutral photograph where they would be scanned again. This was repeated several times to obtain a significant number of images of the brain and thus ensure the consistency of what was obtained while looking at both photographs.
The research results
There were many parts of the brain that were activated in the lovers who participated in the experiment. However, it seems that there are two regions that are of special importance in the sublime experience of being in love.
Perhaps the most important discovery was the activity of caudate nucleus It is a large, “C”-shaped region that is very close to the center of our brain. It is primitive; It is part of what is known as the reptile brain, because this region evolved long before the proliferation of mammals, about sixty-five million years ago. The scans showed that there were parts of the body and tail of the caudate nucleus that became especially active when a lover looked at the photo of the person in love with her.
The brain’s reward system is important in falling in love
Scientists have long known that this brain region directs body movement. But until recently they have not discovered that This huge motor is part of the brain’s “reward system”, the mental network that controls sexual arousal, feelings of pleasure, and motivation to obtain rewards. And what is the neurotransmitter that is released during the activation of the caudate nucleus? Dopamine, a substance closely involved in motivation, that is, it helps us detect and perceive a reward, discriminate between several and wait for one of them. Generate the motivation to get a reward and plan specific movements to get it. The caudate is also associated with the act of paying attention and learning.
In this study, activity was also found in other regions of the reward system, including the septum areas and the ventral tegmental area (VTA). This last region is also associated with the release of a huge amount of dopamine and norepinephrine, which is distributed throughout the brain, including the caudate nucleus. When this occurs, attention narrows, the person appears to have more energy, and You may experience feelings of euphoria and even mania
Based on her study, Helen Fisher radically changed the way we think about love. Love was once considered to involve a range of different emotions ranging from euphoria to despair. After this study, It is concluded that love is a powerful motivational system, a basic mating impulse But why is it an impulse and not an emotion (or a range of emotions)?
The chemical cascade of love
Everything I have described is related to what romantic love (or infatuation) would be, what is felt in the first moments in which we become obsessed by the loved one. For Helen Fisher, romantic love evolved in the brain to direct all of our attention and motivation on a specific person. But this does not end here. To make love more complex, this brain system that generates a force as intense as romantic love It is also intrinsically related to two other basic drives for mating: the sexual impulse (desire) and the need to establish deep bonds with the partner (attachment).
Sexual desire is what allows an individual to perpetuate the species through reproduction with an individual of the opposite sex. The hormones involved in this impulse are androgens, composed of estrogen, although fundamentally it is testosterone that is most committed to this function, both in men and women. The areas that are activated in the brain when there is a sexual impulse are: the anterior cingulate cortex, other subcortical regions, and the hypothalamus (involved in the release of testosterone).
In the case of romantic love, as we discussed, it is related to focusing attention on one individual at a time, in such a way that time and energy is saved for courtship. The neurotransmitter par excellence is dopamine, although it is accompanied by norepinephrine and a decrease in serotonin. The areas that are functional to this system are: mainly the caudate nucleus and in turn the ventral tegmental area, the insula, the anterior cingulate cortex and the hippocampus.
Attachment and its relationship with oxytocin and vasopressin
And finally, as the couple strengthens the bond and deepens their relationship, attachment arises, a system whose function is to allow two individuals to tolerate each other, at least long enough to achieve parenting during childhood. It is closely related to the decrease in dopamine and norepinephrine, which leads to a considerable increase in two hormones that allow this function: oxytocin and vasopressin. The neural circuits that produce such neurotransmitters are the hypothalamus and the gonads.
Each of these three brain systems evolved to serve a specific function for mating. Desire evolved to allow sexual reproduction with almost any more or less suitable partner. Romantic love allowed individuals to focus on only one partner at a time, thereby saving considerable time and energy for courtship. And attachment resulted in men and women being together long enough to raise a child during childhood.
The heart is in the brain
Regardless of the fact that in general such systems appear in the way in which they have been explained (sexual desire, romantic love and finally attachment), it does not always occur in this order. Some friendships (attachment) over the years awaken a deep love that can lead to love or a friendship ruined by a broken heart. Even, It is possible to feel sexual attraction for one person, romantic love for another, and a deep attachment to another person This theory opens a question when trying to explain a behavior that is as interesting as it is unloved in a relationship, infidelity.
In short, it is interesting that we are getting closer to understanding how such a small mass of only 1.3 kg, that is, the brain, can generate something as complex as love, an impulse so strong as to be the subject of so many songs, novels, poems, stories and legends.
