21 papers published on October 12th 2023, have revealed there is more to the brain than previously known. 3300 types of brain cells, a magnitude greater than previous reports, were discovered with the help of the Brain Atlas, a $375 million effort started in 2017. These new discoveries were made possible by new technologies that allowed scientists to probe millions of human brain cells with biopsied tissue or cadavers. This discovery is just the beginning, though, as these discoveries only sampled a small fraction of the 170 billion cells in the human brain. The process of obtaining the cells was lengthy and required several sources such as people who had recently passed away and those undergoing brain surgery.  Scientists attached glass tubes to each cell to inspect their electrical activity, injected dye to make their structure visible, then extracted the nuclei from the cells. Although this new discovery provides an astonishing amount of new data, the amount of cells discovered is only a fraction of the total number of cells within our brains so there could be up to 3300 more types of cells that we have yet to discover.

Mouse brain cells

An article published only two days after the one described above looks further into the 3300 cells types. The article identifies that the cells can be grouped into 461 clusters. In addition, new brain cells were found inside the cerebral cortex, the region of the brain responsible for memory, and language. Furthermore, an article published on the same day claims that neuron cells, responsible for transmitting stimuli, were present alongside the new cells in the samples they received. The article then identifies that from the cells obtained, half were neuronal cells and half were not.

Neurons, identified in half of the new cells, are the fundamental parts of the brain and nervous system. Our most recent topic in AP Biology is neurons and their functions. Neurons have many functions such as receiving sensory input from the external world, sending commands to the muscles, and transforming the electrical signals sent out during this process. The appearance of a neuron consists of three parts: dendrites, an axon, and a soma which can appear like a tree without leaves. Neurons are located all throughout the brain, with 10-20 billion in the cerebral cortex and 55-70 billion in the cerebellum (wikipedia) so it is not surprising that so many were identified in the new cells. Neuron cells are similar to eukaryotic cells in some ways, but not all. Like eukaryotes, they have a cell body that contains organelles. On the other hand, neurons have two branch structures, axons and dendrites, that differentiate them from a typical cell

Although the recent discovery of 3300 new types of brain cells is an astounding advancement in the ongoing research of the brain, this discovery is only a small portion of what lies within the large, independent system, that is our brain. How many cell varieties do you think are still undiscovered? I say hundreds.






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