Introducing the brain: identifying different neuron function (Introduction)

by David Turell , Monday, April 25, 2022, 20:35 (731 days ago) @ David Turell

By analyzing genome processing in individual neurons, new ones are discovered:

https://www.the-scientist.com/modus-operandi/crack-method-reveals-novel-neuron-type-in-...

"...in his lab at Boston University, biologist and biomedical engineer Jerry Chen has developed a technique that allows researchers to do both, mapping neurons within a living mouse’s brain and then assessing their gene expression.

"The new technique, called comprehensive readout of activity and cell type markers (CRACK), combines calcium imaging microscopy with a variation on a DNA labeling approach called hybridization chain reaction–fluorescence in situ hybridization (HCR-FISH) to label and track mRNA. CRACK allows researchers to first observe the electrical firing of neurons in the brain of a live mouse during a behavioral task, and then track the expression of specific genes in slices of the animal’s brain, ultimately linking specific cells and their molecular activities to particular behaviors.

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"The paper describes how the team used CRACK to identify a previously overlooked neuron type, the Baz1a cell, in the primary somatosensory cortex of the mouse brain. According to Chen’s findings, Baz1a cells help coordinate neural activity related to learning in response to tactile sensations on mouse whiskers. Chen says that even though they created CRACK for this specific experiment, they’ve just scratched the surface of how the methodology could be used.

“'Now, if you have a tissue of a thousand neurons, you can actually start to label all eleven, twelve, thirteen, fourteen, fifteen different types of neurons that we know exist,” Chen says. “Then you can ask: How does cell type A communicate with cell type B?” Chen envisions several possible uses for CRACK, including studying the neural function of species beyond mice and humans for which tailored neuroscience tools may not be available, or answering “any question that involves trying to marry molecular information with dynamics—functional information” on the behavior of neurons.

"University of California, San Diego, neuroscientist Takaki Komiyama tells The Scientist that the main benefit of the technique is being able to “define the expression of dozens of genes in a given neuron.” With CRACK, “you can record hundreds of neurons’ activity and pretty precisely identify the cell type of each of those hundreds of neurons,” adds Komiyama, who didn’t work on the paper but helped pioneer the use of calcium imaging over the past two decades."

Comment: we know about 80-100 billion neurons exist in the human brain. If they can have different functions for different processes, that is really like having the equivalent of a trillion neurons or more. No wonder our brain acts like it does. This design is not by chance.