2023-06-20 16:00:00
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The human species has risen as the dominant animal on Earth. He scientific and technological development has brought unprecedented changes in the natural history of the planet, so much so that it has been shaped to meet their needs (sometimes to the detriment of those of other species). All the advances of the species have been fast-paced, something that can only be explained by a differential nuance: intelligence.
Where does intelligence come from?
To better understand this intelligence, it is necessary to delve into its organic support: the brain. This represents 2% of the total body mass in humans. He 76% of its tissue corresponds to the most superficial region and recent regarding its evolution: the neocorteza.
In this extensive territory of the brain are found the higher order cognitive functions that have allowed the development of thought, language, formation of cultures and societies. On the other hand, one of the most used indicators to infer the intelligence of all living beings is the relative weight of your brain with respect to total body mass.
In this sense, the human brain presents the highest rate of all primates. This would explain the achievement of evolutionary milestones necessary for the advancement of the species. For example, the use of tools, collaboration, the development of agriculture and livestock, etc.
Current evidence suggests that there is a direct relationship between the size of the neocortex and the capacity of an animal to build extensive communities, but in recent times, a particular neurotransmitter of the nervous system is being studied to try to understand this evolution: serotonin (5-hydroxytryptamine).
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Functions and particularities of serotonin
Serotonin is one of the main neurotransmitters in the human brain. It has multiple functions that help regulate your balance. despite the fact that It is popularly known as the “happiness hormone”., the truth is that it is not a hormone nor is it limited exclusively to stimulating the mood. In fact, even this last relationship is currently in questionsince several studies question the classical hypothesis to understand psychological disorders such as major depression.
Serotonin has a key role in regulating physiological functions necessary for survival; such as hunger, sleep, pain and sexual response.
His contribution to the processes of learning and memory. That is, to the acquisition of knowledge for further processing through reason. On the other hand, its deficit has been consistently associated with aggressive responses, from suicide to interpersonal violence.
Serotonin, beyond the human brain
There are also cells sensitive to serotonin in other body regions such as the gastrointestinal tract (enteric nervous system). From its contribution, serotonin facilitates the homeostasis of the organism in a broad sense. In fact, the possibility that intestinal neural circuits could serve to explain the relationship between the microbiota and certain mental disorders (gut-brain axis) is not ruled out.
Finally, there is previous evidence that serotonin also contributes to the proliferation and location of neurons in immature brains. It has been described that an excess of it can negatively interfere with both parameters with respect to cortical neurons. It is precisely with regard to this issue that, in recent months, the horizons of human knowledge have broadened.
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Serotonin and human brain growth
There are many hypotheses that for decades have tried to elucidate why the brain differs from that of other living beings. In this sense, various theories have emerged: from the contribution of fire to cooking food even genetic mutations. In this line, it has also recently been suggested that serotonin could help solve this traditional mystery.
The role of serotonin during the gestation process in brain development has already been discussed, especially in the proliferation and location of neurons. To this fact should be added the latest find from a German research teamwho has described how the production of serotonin in the placenta would interact with the HTR2A receptor exclusively in humans, stimulating the production of stem cells.
This phenomenon would result in a comparable and extraordinary production of cortical neurons, and with it in an increase in cortical volume.
However, and despite being an interesting finding with multiple therapeutic applications, it may be simplistic to say that the “happiness neurotransmitter” increases intelligence. First, because serotonin is involved in many other functions than mood. Second, these cerebral bases of intelligence cannot be reduced to the generic size of the neocortical surface, but their functioning and distribution are essential.
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*Joaquín Mateu Mollá is Associate Professor at the International University of Valencia and PhD in Clinical Psychology from the International University of Valencia. This note originally appeared on The Conversation and is published here under a Creative Commons license.
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