(ORDO NEWS) — Neurons communicate through synapses, small contact points where neurotransmitters transmit stimulus from one cell to another. Synapses are part of the brain of almost every animal species, but they usually remain invisible even under an electron microscope.
Synapses are part of the brain of almost every animal species, but they are usually invisible even under an electron microscope. “Electrical synapses are like the dark matter of the brain,” says Alexander Borst, director of biological intelligence at MPI.
A team from his department investigated this rarely studied component of the brain. Using the Drosophila fruit fly as an example, they were able to show how electrical synapses occur in almost all areas of the brain and can affect the function and stability of individual nerve cells.
Neurons communicate through synapses, small contact points where neurotransmitters transmit stimulus from one cell to another. Perhaps we remember this from biology lessons. But that’s not the whole story. In addition to the well-known chemical synapses, there is a second, little-known type – electrical.
George Ammer, a participant in the same study, has long been fascinated by hidden cellular connections. He says that electrical synapses are much rarer and difficult to detect with current methods.
That is why they have hardly been studied so far, and we do not even know elementary things about the brains of most animals. For example, where exactly do electrical synapses originate or how do they affect brain activity.
An electrical synapse, says George Ammer, connects two neurons directly, allowing the electrical current that neurons use to communicate to flow from one cell to another without detours.
With the exception of echinoderms, this particular type of synapse is found in the brains of all animal species studied so far. Therefore, electrical synapses must perform important functions: we just don’t know which ones!
To trace these functions, Ammer and two colleagues, René Vieira and Sandra Fendl, noted an important protein building block of electrical synapses. Thus, in the brain of fruit flies, they were able to show that electrical synapses do not occur in all nerve cells, but in almost all areas of the brain.
The researchers selectively turned off electrical synapses in the area of visual processing and showed that the response of affected neurons to certain stimuli was much weaker. In addition, without electrical synapses, certain types of nerve cells became unstable and spontaneously oscillated.
The results show, according to George Ammer, that electrical synapses are important for various brain functions and can play very different functional roles depending on the type of neuron, so these synapses should also be integrated into connectome research.
A connectome is a map of all neurons and their connections in a brain or region of the brain. This information is often reconstructed from electron microscope images.
The electrical synapses in them are largely invisible. How they might be integrated into connectome research, and what other secrets electrical synapses hold, remains the subject of future research.
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