The neurons of von Economo (or spindle neurons) are only present in the human brain, in bonobos, chimpanzees and gorillas, as well as in whales and elephants. Santiago Ramón y Cajal defined them as giant fusiform cells and as one of the most interesting structures of the brain. They relate to social behavior or the sense of self.
Most of us have heard about mirror cells. However, interestingly, von Economo neurons are not so well known, despite their undeniable transcendence in our behavior. They help us make decisions, shape our identity, erect the framework of consciousness and even that exceptional sense called intuition.
It is striking to know, for example, that of the 100 billion neurons in our brain, only about three hundred thousand are von Economo neurons; but yes, they are up to three times larger. On the other hand, it should be noted that a good part of this data has been known in recent decades thanks to advances in functional magnetic resonance techniques.
Neurologists also point out that the lineage of this unique cell originated 15 million years ago with a common ancestor of hominids: Dryopitecus. Another interesting fact is to know that these cells already appear in the human brain when the fetus reaches 36 weeks of gestation.
In recent years, von Economo neurons are becoming more relevant in the area of cognitive psychology and neuropsychiatry, because they are only found in animals with superior cognitive and social behavior.
Economo neurons: what they are and where they are
The first description we have of von Economo neurons dates from 1925. It was the Austrian psychiatrist and neurologist Constantin von Economo who introduced them to the scientific world with his work The cytoarchitecture of the cortex of the adult human being). He detailed them as spindle-shaped elongated neurons (fusiform), with a size that quadrupled to a pyramidal cell (they can reach between 70-100 μm).
Later, Dr. Von Economo published a new study giving more data. He specified that they were indeed a new cell not described so far. It did not respond to any type of pathology, it was specialized and it was located in the insular turn.
As striking as this discovery may seem to us, it should be noted that it did not acquire great transcendence. In fact it has not been until the 21st century when neuroscience, psychology and psychiatry have put their point of attention in it. The reason? They only appear in animals with superior cognitive and social functions.
Characteristics and location of von Economo cells
Neurologists John M. Allman and Nicole A. Tetreault of the University of California (United States) conducted a study in 2011 to provide new data on spindle cells or von Economo neurons.
We know that they are large bipolar neurons located in the fronto-insular cortex, as well as in the anterior limbic area.
Biologist Karli Watson, from the California Institute of Technology (CALTECH), described its fine architecture in 2005. They are made up of basal and apical dendrites with simple arborization and reduced dendritic spines.
They only appear in great apes and humans, but not in other primates. Also in other animals with complex social behaviors, such as whales and elephants.
They are projection cells and have receptors for vasopressin, dopamine and serotonin.
As we have indicated at the beginning, this type of neurons appear in fetuses from the 36th week of gestation. However, its greatest development appears in the first eight months after birth, accumulating to a greater degree in the right hemisphere.
Functions of von Economo neurons
The fact that von Economo or spindle neurons appear only in humans and animals with more complex social processes gives us a clue to their relevance. It is speculated, for example, that they are typical of brains with greater size, with more complex executive functions and that, in addition, could be the key to understanding, among other things, the evolution of the human species and the appearance of that entity that we call “mind”.
Intuition and decision-making processes
In a study of the University of Iowa (Allman, Watson, Tetreault, and Hakim, 2005) demonstrated that the brain attends information and makes decisions at a faster rate than our conscience can process. In this way, dimensions, such as what we call “intuition” or mere “hunches”, would respond in reality to a very complex neural processing.
It has been discovered, for example, that Von Economo neurons are crucial when making quick judgments based simply on our intuition.
Sense of the self
Von Economo neurons are often defined as the orchestra directors of our brain. Thanks to them, all that complex neural universe is in harmony. Supervises processes, directs thoughts and helps us to concentrate. In this way, it integrates our sense of self as well as our conscience over the years.
Emotions and empathy
If there is anything we know about spindle neurons, they are very large compared to the rest. This allows them to extend to many areas of the brain. So much so that it has been discovered that they are key in emotional processing and that the insula also contains a large number of von Economo neurons.
This implies several things. The first is that it favors the fact that we can attribute an emotional imprint to everything we see. The second is that it mediates empathy and those more “social” emotions, such as shame, love, trust or resentment.
Von Economo neurons and disorders
The abnormal development of spindle neurons is linked to the appearance of various disorders. In this way, psychotic behaviors, characterized by distortions of reality, are a clear example. On the other hand, disorders of thought, language and behaviors -where social anxiety or desire for isolation also appears- would have their origin in this factor.
On the other hand, it is important to know that people with Alzheimer’s, schizophrenia or with an autism spectrum disorder, in turn present a degeneration of this type of neurons. As a particularly striking fact, it has also been proven that people with suicidal tendencies, on the other hand, have a greater number of them.
They are as we see information with great relevance and implication, where neuroscience continues to open up to give us answers and, in turn, new ways of dealing with and intervening in many of these disorders and situations. We will be awaiting more data on this type of neurons that, in some way, define that which makes us more human, and at the same time, incredibly complex beings.