Activity-dependent myelination in prefrontal circuits signals the offset of infantile amnesia

Infantile amnesia, the inability of young children and infants to retain long-term memories, occurs when the neural circuits necessary for memory consolidation are not fully mature. Scientists believe that this phenomenon may be due to an insufficiently developed neural infrastructure. In a study focused on mice, researchers discovered a mechanism that sheds light on the end of infantile amnesia.

Activity in the prelimbic cortex, a specific region of the prefrontal cortex, triggers a series of maturation steps leading to memory persistence akin to that of adult mice. This activity-dependent process involves an increase in brain-derived neurotrophic factor (BDNF), which in turn promotes myelination of the prelimbic circuits.

Myelination, the process by which nerve fibers are insulated with a fatty substance called myelin, is essential for effective neural communication. Myelination occurs through the activation of tyrosine kinase receptor B (TrkB) receptors on oligodendrocyte precursor cells (OPCs). OPCs are cells responsible for producing myelin. The study reveals that disrupting any of these steps during a crucial developmental window delays the offset of infantile amnesia.

Conversely, promoting myelination leads to the premature emergence of memory persistence. This research indicates that developmental myelination in prefrontal circuits is crucial for proper circuit maturation and the development of adult-like memory function.