Myelin emerges as an active regulator of brain plasticity, not just a structural insulator
A study by Professor Carlos Matute of the EHU reinforces a paradigm shift in neuroscience: Myelin goes from being a structural element to being an active component of brain function. Published in Trends in Molecular Medicine, the study shows that myelin not only facilitates the transmission of signals, but also plays an active role in brain plasticity, in other words, the brain's ability to adapt.
In this process, the GPCR receptors, activated by neurotransmitters, act as key regulators of this plasticity in the adult brain. Understanding how myelin, which plays a part in numerous neurological disorders, is regulated opens up new therapeutic opportunities.
Myelin is the structure that surrounds nerve fibers and enables the signals in the brain to be rapidly transmitted. For decades, it has been regarded as a structural component responsible for accelerating nerve conduction. However, recent research shows that it not only acts as an insulator, but also as a structure capable of adapting in real time to neuronal activity.
"Myelin is a dynamic structure that responds to brain activity; it can no longer be regarded as a passive component," said Matute, lead researcher in the study and a professor of the EHU-University of the Basque Country.
The study redefines the role myelin plays in brain biology. Far from being a mere structural support, it emerges as an active component in the brain's adaptation. "Myelin is one of the mechanisms enabling the brain to reorganize itself," concluded Matute. "It is a dynamic component of brain function, not just in terms of its structure."
Neurotransmitters that modulate myelin: A new hub in brain plasticity
This study consolidates a paradigm shift in neuroscience: Myelin not only facilitates the transmission of signals, but also, guided by neuronal activity itself, plays an active role in brain plasticity. Neural plasticity is about the brain being able to reorganize itself and adapt to new situations and stimuli by creating new neuronal structures and connections. But how is this process regulated in the adult brain?
The study shows that the organization and dynamics of myelin are actively controlled by neuronal signals. "The evidence indicates that G protein-coupled receptors (GPCRs), which are activated by neurotransmitters, form a central hub that connects neuronal activity with myelin remodeling in the adult brain," explained Marta Cimadevila, a post-doctoral researcher in Carlos Matute's team.
The GPCRs act as key sensors of neurotransmitters, such as glutamate, acetylcholine, and histamine. Their activation triggers cell mechanisms that regulate the formation of new myelin sheaths, the remodeling of existing ones, and the functional adaptation of neural circuits. This mechanism directly connects synaptic activity with structural changes in the myelin, thus providing a molecular basis for plasticity in the adult brain.
Myelin formation is being increasingly recognized as a dynamic, adaptive process regulated by oligodendrocytes, the cells that produce myelin in the brain throughout an individual's lifetime. This new framework identifies oligodendrocytes as active components that interpret the chemical signals released by the neurons.
In addition to providing electrical insulation, myelin can act as an energy reserve in situations of metabolic stress, and that redefines its role in the brain not only in structural, but also in metabolic terms. Myelin degeneration and damage are involved in a wide range of neurological disorders, from demyelinating diseases to neurodegenerative and neuropsychiatric disorders. According to the study, GPCR-mediated signaling could become a strategic target for modulating myelin and developing new therapies for neurological diseases.
This article was originally published on MedicalXpress Breaking News-and-Events.