Brain Science Breakthrough

Tuesday, September 26, 2023

Every so often, new scientific discoveries can challenge established principles and change the way we think about the world.

A recent breakthrough in neuroscience research has accomplished just that with the discovery of a brand-new cell type in the brain.

For several decades, neuroscience textbooks have stated that there are two distinct categories of cell types in the brain: neurons and glial cells.

Neurons are the workhorses of the brain responsible for sending and receiving signals that allow us to function. On the other hand, glial cells are the helpers that provide support and protection to neurons.

While these two cell types work closely together, they are inherently distinct from one another — or so we thought until now.

A recent article in Nature titled “Specialized astrocytes mediate glutamatergic gliotransmission in the CNS” introduces the groundbreaking discovery of a new cell type in the brain that is a combination of both a neuron and a glial cell.

One of the defining features that distinguishes neurons from glial cells is that neurons can release small molecules, called neurotransmitters, to communicate with one another.

It was previously thought that glial cells cannot produce neurotransmitters and do not engage in direct communication with neurons using these molecules.

The existence of a hybrid neuro-glial cell type has been a longstanding and controversial debate in the field of neuroscience, but these new findings provide definitive evidence of their existence and may have finally put this debate to rest.

In this study, the authors identified a subpopulation of astrocytes, a type of glial cell, that demonstrate the unique ability to release a neurotransmitter called glutamate.

These glutamatergic astrocytes make up a small portion of all astrocytes in the brain, which likely explains why they were so difficult to identify previously.

Modern advances in RNA sequencing technology now allows for the analysis of single cells in the brain instead of a pooled population of cells, increasing the sensitivity of this technique and making it possible to identify rare cell types, such as this hybrid neuro-glial cell.

Following the identification of this cell type, the researchers also performed rigorous experiments to define their functions in the brain.

In addition to being able to communicate with other neurons using glutamate, these hybrid cells also strengthen signaling between neurons to aid memory formation and dampen the excessive excitation that occurs during seizures.

The authors suggest that this potentially means that the loss of glutamatergic astrocytes may play a role in diseases where neuronal circuits are in a constant state of overactivation, such as Parkinson’s disease.

The discovery of this new hybrid neuro-glial cell type in the brain opens the door to many new and exciting studies.

A better understanding of why this hybrid cell type exists and how it functions under normal versus disease conditions may reveal new therapeutic targets for neurological diseases.