Professor William Richardson | What Mice in Mazes Can Teach Us About Working Memory

Oligodendrocytes are highly specialized cells in our brain and spinal cord. These cells wrap some axons (long wire-like extensions of neurons) with a special multi-layered membrane called myelin – a bit like the insulation on electrical wires. This allows electrical impulses to travel much faster.

What decides which axons get wrapped? Oligodendrocytes and their precursor cells can detect electrical impulses, and this stimulates them to wrap the most-active axons, through a process called ‘adaptive myelination’. During learning, when neurons and their axons are most active, adaptive myelination goes up as well.

Professor William Richardson from University College London is an expert in the development and function of cells in the nervous system. His team conducted a series of experiments to understand the role of oligodendrocytes and myelination in working memory training.

In their experiments, the team tested the working memory of genetically modified mice that don’t produce as many oligodendrocytes as normal mice. They compared the mutant and normal mice for their ability to learn and remember where food treats were located in a maze.

The normal mice were able to remember where to find the treats, getting it right nearly every time, but the genetically modified mice just could not remember.

Strikingly, mice that were best at the maze test had the highest rates of oligodendrocyte and myelin production. The more new oligodendrocytes they produced during training, the faster they found the treats. This suggests that these cells play a role in strengthening working memory by reinforcing the connections between neurons or by coordinating activity across the brain.

This work from the Richardson lab provides a striking demonstration of the importance of oligodendrocytes and myelin for mechanisms of learning and memory. In future, this could help us develop treatments for cognitive disorders.