From a tiny tissue sample, not greater than a chia seed, scientists achieved an objective that in the past seemed unattainable: drawing a high resolution map of the structure and connections between the brain cells of a mouse, a “milestone” for neuroscience.
This was possible thanks to the seven -year work of a team of more than 150 neuroscientists and researchers from various institutions, grouped in the Microns project. Even based on data from a single cubic millimeter of tissue, this diagram – scientists assist – is the largest and most detailed brain of a mammal to date.
The wiring scheme and its data, with around 84,000 neurons and about 500 million synapses, are available for free through the microns explorer, with a size of 1.6 petabytes (equivalent to 22 years of continuous HD video). These offer “unprecedented information” about brain function and the organization of the visual system.
Microns advances, for which artificial intelligence tools were used, are published in ten articles in Nature and Nature Methods, and “mark a milestone for neuroscience, comparable to that of the human genome project in its transformative potential,” summarizes David A. Markowitz, work coordinator.
And it is that a map of connectivity, the shape and neuronal function from a portion of the brain the size of a grain of sand is not only “a scientific wonder”, but a step towards the understanding of the elusive origins of thought, emotion and consciousness.
But, in addition, it has implications for disorders such as Alzheimer’s, Parkinson’s, autism and schizophrenia, which imply interruptions in neuronal communication.
“If you have a damaged radio and you have the circuit diagram, you will be in a better position to fix it,” says Nuno da Costa, from the American Institute Allen. “We are describing a kind of ‘Google map’ or plane of this grain of sand. In the future, we can use it to compare the brain wiring of a healthy mouse with that of a disease model.”
To complete this Atlas, scientists from the Baylor Medicine School (EU) used specialized microscopes to record the brain activity of a tiny portion of the visual mouse cortex while watching various videos.
Subsequently, researchers at the Allen Institute took that cubic millimeter of the brain and divided it into more than 25,000 fine layers, and used a series of electronic microscopes to collect high -resolution images of each portion.
Finally, another team from Princeton University (EU) used artificial intelligence and automatic learning to rebuild cells and connections in a three -dimensional volume.
Combined with the records of brain activity, the result is the wiring diagram and functional map of the largest brain to date, with more than 200,000 cells -84,000 neurons-, four kilometers of axons (branches that connect with other cells) and 523 million synapses (connection points between the cells).
Read more: they describe how neurons create sophisticated maps in the brain to guide us
New neuronal brain map achieves functional analysis
The findings reveal new types of cells, characteristics and organizational and functional principles. Among the most surprising, the discovery of a new principle of inhibition in the brain.
Previously, scientists considered the inhibitory cells (those that suppress neuronal activity) as a simple force that cushions the action of other cells.
However, they discovered a much more sophisticated level of communication: these do not act randomly, but are highly selective with the exciting cells to which they are directed, creating a coordination and cooperation system throughout the network.
While this research is important, broader maps are needed to study complete circuits.
The American National Health Institutes are underway by the Brain Connects program, whose objective in the next four years is to break the technological barriers that would prevent a complete mouse brain, explains Forrest Collman, of the Allen Institute.
“If we are able to develop technology, we can start working with a complete mouse brain in five years and then it will take between five and ten years to collect data,” although it is still difficult to know, says Collman.
Until recently, neuroscience had worked with partial maps or in the best full cases but of species with a few hundred or thousands of neurons. But in recent years things have changed radically.
In 2024, for example, the full connectoma – diagram of the neuronal connections – of the vinegar fly, “Drosophila Melanogaster” was achieved, with 140,000 neurons and 50 million synapses.
Also in 2024 Harvard University and Google Research published a 3D reconstruction with synaptic resolution of a piece of human temporary cortex also of a cubic millimeter.
While these were very important steps, what is published now is “the best thing that has been done, it has no precedents,” summarizes Juan Lerma, of the Institute of Neurosciences of Alicante (CSIC-RUMH), who does not participate in the studies. The scientist highlights that, in addition to the nanometric scale structure of brain cells, its functional analysis was achieved, and there is the key.
Apart from knowledge -this is nothing more than the tip of the iceberg of what is to come -these findings will serve to develop models of superpotent based on neuronal networks, which, for example, will allow to understand brain diseases, underline Lerma, of the Royal Academy of Sciences of Spain.
With EFE information
Inspy, discover and share. Follow us and find what you are looking for on our Instagram!
