In an effort to map the entire human brain at a cellular level, researchers have discovered that we possess more than 3,000 different types of brain cells. The study is shedding light on the profound question: What really makes us human?
Published today in a series of 21 papers across several journals, a global team of researchers has unveiled these new insights about the cells that make up our brains and those of other primates.
This research marks a significant advancement in our understanding of the nervous system’s cellular components and highlights what makes the human brain unique.
For the study, which was facilitated by the National Institutes of Health’s Brain Research Through Advancing Innovative Neurotechnologies® (BRAIN) Initiative, hundreds of scientists collaborated to explore the cellular architecture of primate brains.
The goal was to develop innovative techniques that would allow for studying the human brain’s organization with unparalleled precision.
A profound understanding of the brain at the cellular scale is not just a quest for knowledge. Recognizing the cellular basis of brain disorders and diseases could pave the way for improved treatments and interventions.
A notable institution involved in this endeavor is the Allen Institute for Brain Science. This team led five studies and made significant contributions to three others.
One such study, undertaken jointly by scientists at the Karolinska Institute and the Allen Institute, employed a method called single-cell transcriptomics. The results were staggering. They revealed that the human brain boasts more than 3,000 distinct cell types.
“I view this as a pivotal moment in neuroscience, where new technologies are now allowing us to understand the very detailed cellular organization of the human brain and of other primate brains,” said Dr. Ed Lein, who led several of the newly published studies.
“At its core, this body of work is a triumph of molecular biology: Differential gene usage can be used to define cell types, and the tools of genomics could be used to create the first drafts of high-resolution, annotated maps of the cells that make up the entire human brain.”
Among the studies’ queries were fundamental questions regarding the distinction between individual human brains at the cellular level, the differences between human and ape brains, the range of brain cell types, and the evolution and maturation of these cells.
Initial studies focusing on single regions of the human cortex identified over 100 different brain cell types. The new findings, however, expand this data across the entire brain, revealing many more distinct cell types – including some types that had never been characterized before.
These investigations are affiliated with the NIH’s BRAIN Initiative Cell Census Network (BICCN), launched in 2017 with the aim of cataloging brain cell types. The results highlight the scalability of innovative cellular and molecular methodologies to address the vastness and complexity of the human brain.
“The present suite of studies represents a landmark achievement that continues to build an important bridge toward illuminating the complexity of the human brain at the cellular level,” said Dr. John Ngai, Director of the NIH BRAIN Initiative.
“The scientific collaborations forged through BICCN, and continuing in the next phase in BICAN, are propelling the field forward at an exponential pace; the progress – and possibilities – have been simply breathtaking.”
For these studies, the experts used postmortem brain tissues from donors and healthy living tissues from surgical patients.
The information from the research will be integrated into the Human Cell Atlas, a global project, which is aimed at creating a detailed reference atlas of cells across the entire human body.
The research is published in the journal Science.
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