For thousands of years, humanity has looked at the moon with awe and horror in light of its supposed evil influence. Then Johannes Heveliusthe son of a wealthy Polish brewer, built a homemade telescope in what is now Gdansk and sat down every night to closely study the extraterrestrial world. In 1647 he published the first book Moon cards.
Now, Tomas NowakowskiThe 40-year-old neuroscientist, who grew up in the same city as Hevelius, is leading the creation first draft of the map the human brain at all stages of its development – from embryo to adult life. The researcher says he feels like one of those early cartographers. “Humans would never have landed on the moon if we had not had a map of the lunar surface. All the great advances and achievements in history began with the creation of accurate maps,” he told EL PAÍS.
Novakovsky is one of the leaders BRAIN Initiativean American project launched by President Barack Obama in 2013 to map the human brain. This effort has already raised a huge budget 4.5 billion euros ($5.21 billion). “The brain, the source of our thoughts, ideas and imagination, continues to be the most important unexplored entity. To understand it, we must start by understanding the list of its components,” says Nowakowski of the University of California, San Francisco.
This is a monumental work. During pregnancy, one cell – an egg fertilized by a sperm – multiplies, and, starting from the third week, a rudimentary rudiment develops. nervous system a process begins and ends 86 billion neurons and trillions of connections between them. In this unimaginable choreography inside the fetal skull, some cells take alternative paths. Novakovsky provides estimates according to which 15% children and adolescents live with neurodevelopmental disorders such as autism, schizophrenia or attention deficit hyperactivity disorder.
The international BRAIN Initiative consortium is now using emerging technologies that can analyze which genes are active in each cell to produce the first draft of a dynamic map of the developing brain. “Human tissue can be obtained from surgical procedures or from post-mortem brains, which are usually discarded. If cells are isolated from tissue quickly enough, they can be cultured in vitro within hours or, in some cases, days. This gives us a unique opportunity to study development in humans,” says Nowakowski. So-called pluripotent stem cells, derived from spare embryos from fertility clinics or reprogrammed adult cells, now also make it possible to mimic the early stages of brain formation in the laboratory.
These recent findings are the first steps toward understanding the specific times during pregnancy when risk is highest. brain tumors or neurological developmental abnormalities. Genes that are involved in mental disorders such as autism and schizophrenia, Nowakowski explains, are activated with greater intensity at the end of pregnancy, precisely at stages that differ most from the functioning of mice and other laboratory animals. To understand how the human brain labyrinth is formed, you need to have your own atlas.
The brain contains thousands of subtypes of cells, each of which is highly specialized in its functioning: neurons of thinking, astrocytes, which play a supporting role, oligodendrocytes which function as an insulating layer of nerve cables and microglia that cleanse the nervous system of waste. The consortium found that during fetal development, cells are extremely flexible in their identity, allowing them to transform into other cell types in the adult brain. This flexibility is also their weakness. Researchers have discovered a type of progenitor cell present in the second trimester of pregnancy that can generate neurons, as well as oligodendrocytes and astrocytes. An incurable brain cancer called glioblastoma has cells similar to this precursor, providing clues to the tumor's origins.
BRAIN Initiative Cell Atlas Network announced the results of half a dozen studies, published in Nature This week. The first line of the article resembles the work of the Spanish Santiago Ramon and Cajalthe man who, armed with a microscope and chicken cerebellums, imagined first objective evidence in 1888 the nervous system was organized into individual cells. “Almost all modern neuroscience is based on the concepts proposed by Cajal,” says Nowakowski. “He was a visionary even in areas that we still don't know how to study. I'm convinced that his vision will resonate for many years to come,” adds the UCLA professor.
Spanish neuroscientist Rafael Yuste. was there in the early days of the BRAIN initiative. He says that one day in September 2011 in a British mansion Chicheli HallTwo dozen experts in the brain and the study of millionth-of-a-millimeter structures gathered to discuss possible ways to collaborate. Yuste stood up and made comments that caused a lot of controversy: he suggested analyzing all the neurons one by one. Studying just a few of them, he said, was like trying to watch TV while looking at a single pixel. Among the voices claiming that this idea is not feasible, American geneticist George Churchwho had been advocating for a comprehensive project to study human DNA since 1984, stood up and declared that in science “nothing is impossible.” The White House accepted this proposal, and in early 2013, Obama solemnly announced the official launch of the project. “As humans, we can identify galaxies light-years away, we can study particles smaller than an atom. But we still haven't solved the mystery of the three pounds of matter that sits between our ears.” the president said.
Yuste, a professor at Columbia University, is encouraged by the initiative's newest results. “This atlas of cell types is not only essential for the scientific understanding of how the brain develops—which is amazing when you consider that it assembles and organizes without any external guidance—but is also fundamental information for understanding the changes and pathologies that occur during pregnancy and early life,” he says. “These results show how sustainable investment in the development and application of new methodologies is critical in science and medicine,” adds Yuste, who is working on plans for the National NeuroTech Center in Spain.
Two years ago, neuroscientist Hongkui Zeng's team presented the most complete mapping of the adult rodent brain: a pea-sized organ containing just 70 million neurons and 5,300 types of cells. Zeng and his colleagues at the Allen Institute for Brain Sciences in Seattle are now focusing their attention on cells that are essential for the functioning of the nervous system: GABAergic inhibitory neuronswhich act as a break from the brain, reducing its activity to facilitate the transfer of information. These neurons, according to the researchers, continue to develop after birth, especially in areas of the brain associated with learning, emotion and decision-making. “This means it may take a longer period than previously thought to intervene and help the brain reorganize, especially for children with developmental disabilities,” the Allen Institute said in a statement.
Neuroscientist Jullermina Lopez Bendito talks about a “quantitative leap” in her field of research. “Until now, we have had cell atlases of predominantly adult brains that provide a static view of cell identity. This collection of papers turns that snapshot into a moving movie: it reconstructs the time progression and cell lineages that give rise to the developing brain,” says the researcher from the Institute of Neurosciences in Alicante, Spain.
López Bendito leads a lab that is trying to understand the dense network of connections between brain cells. She notes that the consortium, in which she was not involved, mapped various species of mammals, from mice to humans, identifying specific characteristics of humans and other primates, such as the longer period of generation of new neurons and diversification of the cerebral cortex after birth. “These temporal differences may underlie both human cognitive abilities and our greater vulnerability to genetic mutations or environmental changes during development,” the neuroscientist notes.
In 1888, Santiago Ramon y Cajal, alone with his microscope, embarked on an impossible mission to map the brain millimeter by millimeter. His work culminated in the publication in 1904. Texture of the nervous system of humans and vertebrates. a colossal work of 1800 pages This was accompanied by a warning that completing the construction of neuroscience would require many centuries of work.
Tomas Nowakowski is more optimistic. “I don't think we're centuries or even decades away. I've been impressed by the speed at which artificial intelligence has advanced, especially in recent years, in emulating certain cognitive processes through computational models,” the researcher reflects. “I believe we are rapidly approaching the point where theory and modeling will be able to make predictions about what cells and molecules are needed for brain structure and function. And we will have the technology needed to test those predictions.”
Register for our weekly newsletter to get more news in English from EL PAÍS USA Edition
