Science advances little by little, but without a doubt, its results are increasingly revealing. One of his latest discoveries has been the discovery of a type of neurons named "Rosehip Neurons". At the moment, everything is unknown around this type of neurons.
Its name comes from its resemblance to rosehip due to the branching of the axons of this neuron. Some authors affirm that "the dense bundle that the axon of each brain cell forms around the center of the cell looks like a rose after having detached its petals".
The finding is so recent that trying to explain how it works is really complex. The data obtained to date comes from research at the University of Szeged (Hungary) and the Allen Institute (United States). So far, the information obtained suggests that they could be exclusively human neurons. Researchers think they might be present in primates, but that's just a hypothesis in the absence of more studies.
Through post-mortem brain tissue samples from two adult men, sections of the upper layer of the cortex were taken. It is the outermost region of the brain and is what differentiates us from other animals. This brain region is what provides us with human consciousness and other types of functions that are considered uniquely human.
"We don't really understand what makes the human brain special. Studying the differences at the cell and circuit level is a good place to start, and now we have new tools to do that." -Ed Lein, Researcher-
Neuronal investigations are also carried out with mice, and apparently there is no trace of rosehip neurons in rodents. This exclusivity involves several important points. On the one hand, they cannot be studied in mice, therefore, it is impossible to extrapolate the data. On the other hand, since they are -for the moment- exclusively human neurons, they could be important to explain different psychological disorders and specific functions at the brain level..
As stated by Joshua Gordon, director of the National Institute of Mental Health: "It may be that to fully understand psychiatric disorders, we need to have access to these special types of neurons that exist only in humans.".
From the University of Szeged (Hungary), they discovered that these types of neurons only come into contact with pyramidal neurons. According to different investigations, rosehip seems to be an inhibitory neuron. But what is an inhibitory neuron?
"Rosehip neurons synapse with other types of cells in a different part of the human cortex, known as pyramidal neurons." -Gábor Tamás, researcher-
They are neurons that slow down the activity of other neurons in the brain. This data could indicate that these neurons would control the flow of information in a very specialized way. However, it is not yet known how they influence and what their role really is..
Gábor Tamás, a neuroscientist at the University of Szeged, assures that "if you think of all the inhibitory neurons like the brakes of a car, the rosehip neurons would let the car stop in very particular places. They would be like brakes that only work in grocery stores, for example, and not all cars (or animal brains) have them. This particular cell type can stop in places other cell types cannot stop. ".
One of the goals of future research is to find out if these neurons are found in more parts of the brain. On the other hand, it will delve into their function and the role they play, since they still represent an unknown. Researchers are also interested in whether they are exclusively human or can be found in other types of animals..
Another objective is to try to find this type of neurons in post-mortem human brains of people with neuropsychiatric problems. In this way, it could be known to what extent this type of neurons plays a leading role in certain neuronal alterations and / or psychological and psychiatric aspects. Can they significantly alter behavior? How do they influence our behavior? These are some of the unknowns that are intended to be cleared.
Without a doubt, and despite all the advances, the brain continues to represent a great mystery to science. And with this discovery, we realize once again how much we still have to know about ourselves. So we've already found a new treasure chest. Now we just need to see what secrets it hides.
Boldog, E., Bakken, T., Tamás, G., et als. (2018). Transcriptomic and morphophysiological evidence for a specialized human cortical GABAergic cell type. Nature Neuroscience, 21, 1185-1195.