Scientists have long understood that our brain is divided into separate areas, each designed for specific functions. For example, the visual cortex processes what we see, while the motor cortex controls movement. However, the formation mechanisms of these regions and how their neural building blocks differ remain a mystery.
A published study Naturesheds new light on the cellular landscape of the brain. Researchers at the Allen Institute for Brain Science used an advanced method called BARseq to quickly classify and image millions of neurons in nine mouse brains. They found that while some areas of the brain share the same type of neurons, the specific combination of these cells gives each area a different “signature,” similar to a cell’s ID card.
The team then investigated how sensory input affects these cellular signatures. They found that mice deprived of vision underwent a significant reorganization of cell types in the visual cortex that blurred distinctions from neighboring regions. These shifts were not limited to the visual field, but occurred to a lesser extent in half of the cortical areas.
The research highlights the key role of sensory experience in establishing and maintaining the unique cellular identity of each brain region.
D., Ph.D., study co-author and research assistant at the Allen Institute. “BARseq allows us to see with unprecedented sensitivity how sensory input affects brain development,” said Xiaoyin Chen. “These broad changes show how important vision is in shaping our brains, even at the most basic level.”
A powerful new brain mapping tool
Collecting data from a single cell across multiple brains has previously been challenging, says co-author and scientist Mara Ryu of the Allen Institute. According to him, BARseq is cheaper and less time-consuming than similar mapping technologies and allows researchers to examine and compare the molecular architecture of the entire brain in different people.
BARseq tags individual brain cells with unique RNA “barcodes” to track connections in the brain. These data, combined with gene expression analysis, allow scientists to locate and identify large numbers of neurons in tissue slices.
In this study, scientists used BARseq as a standalone method to rapidly analyze gene expression in intact tissue samples. In just three weeks, researchers mapped more than 9 million cells in eight brains.
Chen said BARseq’s scale and speed provide scientists with a powerful new tool to gain a deeper understanding of the intricacies of how the brain works.
“BARseq allows us to move beyond mapping what a ‘model’ or ‘standard’ brain looks like and start using it as a tool to understand how the brain changes and diversifies,” Chen said. “With this kind of efficiency, we can ask these questions in a more systematic way that would be unthinkable with other methods.”
Chen and Ryu emphasized that the BARseq method can be used free of charge. They hope their research will encourage other researchers to use it to study principles of brain organization or the increase in cell types associated with disease.
“This isn’t something only big labs can do,” says Ryu. “Our study is proof of principle that BARseq enables a wide range of experts in this field to use spatial transcriptomics to address their own questions.”
Source: Port Altele
