Brain circuits change throughout life, and researchers in California have discovered a mechanism for one such change: the thickening of the myelin sheath that surrounds nerve fibres and helps neurons to fire.

Michelle Monje and her co-workers at Stanford University School of Medicine studied mice that had been engineered so that light can stimulate neurons in the brain's premotor cortex. This stimulation resulted in the generation of more cells called oligodendrocytes, which make myelin, and a thickening of the myelin sheath in this and other brain regions. Furthermore, mice that were stimulated with light and had thicker myelin showed better motor function than normal animals.

The results could point to ways of boosting myelin formation in neurodegenerative diseases such as multiple sclerosis, the authors say.

Science http://doi.org/r9g (2014)