Myelin is the structure that surrounds nerve fibres 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 Carlos 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 reorganise itself,” concluded Matute. “It is a dynamic component of brain function, not just in terms of its structure,” he added. Myelin is involved in numerous neurological diseases, ranging from multiple sclerosis to neurodegenerative disorders. So understanding how it is regulated opens up new therapeutic opportunities.

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 reorganise 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 organisation 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 remodelling 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 remodelling 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 recognised 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 signalling could become a strategic target for modulating myelin and developing new therapies for neurological diseases.

Additional information

Carlos Matute is professor of Human Anatomy and Embryology at the EHU, lecturer in the EHU’s Department of Neurosciences, researcher at IIS Biobizkaia and lead researcher of CIBERNED (Center for Networked Biomedical Research into Neurodegenerative Diseases).

Marta Cimadevila is an ARISTOS-CIBERNED post-doctoral researcher in the EHU’s Department of Neurosciences, and a member of Carlos Matute’s research group.