Scientists in Cork have discovered that the microbes that live within our bodies can play a major role in regulating the substance that surrounds and impacts on the effectiveness of our nerve and brain tissue.
The finding could help with the development of treatments for disorders, like multiple sclerosis, that are caused by a deficiency of the substance, myelin.
Myelin is extremely important in the efficient operation of the nervous system, because it conducts the electrical signals that turn thoughts into actions and feelings.
The researchers at the APC Microbiome Institute and Department of Anatomy at University College Cork worked with mice that had no microbes in their gut.
They found that the animals displayed evidence of having increased myelin-related gene expression - the process through which genetic instructions are turned into genetic products, like brain or nerve cells.
In particular, they found the impact was specific to the area of the brain that is fundamentally important to good cognitive function, the expression of anxiety and social behaviours.
The scientists, led by Professor John Cryan, Dr Gerard Clarke and Alan Hoban, were able to see the extent of this myelination using a powerful microscope.
The research, published in the journal 'Translational Psychiatry', also discovered that the introduction of normal gut bacteria to the mice led to a reversal of aspects of the myelination process.
The team says that as well as explaining the processes involved in disorders caused by myelin, their discovery also contributes to a growing body of research suggesting the microbiome can have a major influence on brain processes.
"It is likely that key signals from the gut to the brain provide a brake on myelination processes," said Prof Cryan in a statement.
"Understanding what these may open innovative gut microbiome-based strategies for tackling myelin-related disorders".