These Cells Spark Electricity in the Brain. They’re Not Neurons.
Published in Brain/Neurology.
For decades, researchers have debated whether brain cells called astrocytes can signal like neurons. Researchers recently published the best evidence yet that some astrocytes are part of the electrical conversation.
A brain is nothing if not communicative. Neurons are the chatterboxes of this conversational organ, and they speak with one another by exchanging pulses of electricity using chemical messengers called neurotransmitters. By repeating this process billions of times per second, a brain converts clusters of chemicals into coordinated actions, memories and thoughts.
Researchers study how the brain works by eavesdropping on that chemical conversation. But neurons talk so loudly and often that if there are other, quieter voices, it might be hard to hear them.
For most of the 20th century, neuroscientists largely agreed that neurons are the only brain cells that propagate electrical signals. All the other brain cells, called glia, were thought to serve purely supportive roles. Then, in 1990, a curious phenomenon emerged: Researchers observed an astrocyte, a subtype of glial cell, responding to glutamate, the main neurotransmitter that generates electrical activity.
In the decades since, research teams have come up with conflicting evidence, some reporting that astrocytes signal, and others retorting that they definitely do not. The disagreement played out at conferences and in review after review of the evidence. The two sides seemed irreconcilable.