a “volume button” for memory and learning

It is a discovery that is revolutionizing the way we think about memory and learning. A new study from Dartmouth College (USA), published in Proceedings of the National Academy of Sciences, reveals that our brains have a “molecular volume knob” that is used to control electrical signals that pass through synapses and neurons. It would therefore have a crucial role to play in the amount of neurotransmitters released, which changes the number and characteristics of neurons activated in the brain’s circuits. This remodeling of the strength of synaptic connections is at the origin of learning and memory formation.

The discovery of this control mechanism and the identification of the molecule that regulates it could help researchers in their search for ways to manage neurological disorders, particularly Alzheimer’s disease, Parkinson’s disease or even epilepsy. “The synapses of our brain are very dynamic and speak in a series of whispers and screams, schematically Michael Hoppa, assistant professor of biological sciences at Dartmouth and head of the firm. This discovery puts us on a straighter path to being able to cure stubborn neurological disorders. “

A modulation of our brain messages

How does this “molecular button” work? Thanks to synapses, tiny points of contact that allow neurons in the brain to communicate at different frequencies. The brain converts electrical inputs from neurons into chemical neurotransmitters that travel through these synaptic spaces and are the source of our learning and memory.

Two functions support these memory and learning processes. The first, called facilitation, is a series of faster and faster peaks that amplify signals and change the shape of a synapse. The other, depression, reduces the signals. Together, these two forms of plasticity keep the brain in balance and prevent neurological disorders such as seizures. “With age, it is essential to be able to maintain these synapses. We need a good balance of plasticity in our brains, but also the stabilization of synaptic connections.”explains Michael Hoppa.

Focusing on the hippocampus, the area of ​​the brain where our learning and memories are formed, the researchers found that the electrical spikes are delivered as analog signals whose shape affects the extent of the released chemical neurotransmitter. through the synapses.

Basically, it works as a dimmer with variable settings, not as a switch with “on” and “off” buttons. According to scientists, this dimmer allows you to modulate the power of brain circuits.

The brain, “supercomputer” low frequency

In addition to finding that the electrical signals crossing synapses in the brain’s hippocampus are similar, the researchers also identified the molecule that regulates electrical signals. Called Kvβ1, it affects our learning, memory and sleep.

They also discovered the processes that allow the brain to have such high computing power at such low energy. A single analog electrical pulse can carry more information, allowing for better control with low frequency signals. “It helps us understand how our brains are able to work at supercomputer levels with much lower electrical pulse frequencies and the energy equivalent of a refrigerator light bulb. The more we learn about these levels of control, it also helps us understand. how our brain is so efficient “, says Prof. Hoppa.

The research team now wants to focus on the influence of this molecular system on changes in brain metabolism that occur during aging and cause common neurological disorders.