A study by City University of Hong Kong (CityU) reveals for the first time that schema-like learning can foster the growth and regeneration of brain myelin, thereby enhancing the synchrony of neural networks.

The findings might be helpful for the treatment of central myelin diseases caused by ageing, severe depression and Alzheimer's disease, and for improving cognitive function.

Brain myelin is a lipid-rich substance surrounding the neuron axons. It serves to insulate the neuron axons, increase the rate at which information is passed along the axons and protect the neurons.  

The team led by Professor Li Ying, Chair Professor in the Department of Biomedical Sciences, has been engaged in the study of the association between myelin formation and memory for years. The researchers discovered that schema-like learning and memory consolidation can foster the growth and regeneration of brain myelin, and thus enhancing the synchrony of neural networks, and improving both learning and memory capability. 

The study also revealed the pathological mechanisms of central myelin diseases such as multiple sclerosis and cognitive impairment.

Schema-like learning refers to learning through repetition. Language learning is an example. Once a memory schema is established, new knowledge of the same category can be absorbed and mastered quickly.

From the experiments conducted by Prof Li’s team, the rats, having developed the memory schema after multiple flavour-place paired associates, are able to learn new flavour-place paired associates quickly. It was also noted that the myelin of the rats, in the process of developing memory schema, grows substantially.

On the other hand, the rats, upon consuming medicine for demyelination to interfere with the growth and development of myelin, have difficulty in developing memory schema and are unable to learn new knowledge. In addition, the transmission of information within the neural circuits and the synchrony of neural networks are also negatively affected.    

“The discovery of the key role of myelin in advanced cognitive memory and its function in the synchrony of neural networks is an important breakthrough. This has helped shed light on the pathological mechanisms of central myelin diseases such as multiple sclerosis, Alzheimer's disease, chronic severe depression, cognitive impairment, as well as problems related to degenerative learning and impaired memory,” Professor Li said.

The team’s paper titled “Schema-like learning and memory consolidation acting through myelination” was published in The FASEB Journal of the Federation of American Societies for Experimental Biology.

“We will continue our schema-like learning and memory consolidation experiment with rats. We will explore the use of cutting-edge technology in neuroscience, such as photogenetic technology, chemical genetic technology and other methods to wake up the oligodendrocytes, and thus accurately control the growth and regeneration of myelin. We hope to find out whether this could help improve cognitive impairment caused by ageing, severe depression and Alzheimer’s disease,” Professor Li added.

Photogenetic technology, making use of new photonic techniques, targets at selecting and opening up certain cells of organisms to study the special functions of their neurons; while chemical genetics technology is a method of using small molecule organic compounds to systematically interfere with and explore intracellular biological processes in order to identify the biological macromolecules involved in these biological processes.

A well-known academic in biomedical research, Professor Li has recently been invited to serve as a member of the Shenzhen–Hong Kong Innovation Research Institute for Brain Science. He is committed to advancing research in brain science in the Greater Bay Area.