Limbered up: The neurons shown here, transplanted from an embryo into the brain of a young mouse, help the brain adapt.
Rejuvenating the Brain
Neurons transplanted from fetal animals make older brains act young
Source: “Cortical plasticity induced by inhibitory neuron transplantation”
Arturo Alvarez-Buylla, Michael P. Stryker, Sunil P. Gandhi, et al.
Science 327: 1145-1148.
Results: By transplanting fetal neurons into young mice, researchers induced the animals to rewire neural circuits in their visual system.
Why it matters: Rodents and other animals, including humans, experience a period of neural plasticity before the brain circuitry becomes fixed. Researchers hope to enhance this innate capacity in order to improve healing after brain injury and other neurological problems in adulthood. This study was the first to show that animals can be induced to undergo a second round of flexibility. Pinpointing the specific molecules that made it possible could inspire new treatments.
Methods: The researchers took neurons of a specific type, called inhibitory neurons, from the brains of fetal mice and grafted them into newborn or young mice. Then they gauged neural plasticity by measuring changes in the animals’ brains after they were blinded in one eye. The mice experienced the normal period of neural flexibility in the visual system at around 28 days. But a second period of plasticity occurred at around 35 days, when the visual circuitry is normally fixed. Its timing corresponded to the age of the transplanted cells, which suggests that the transplant triggered it.
Next steps: Researchers plan to isolate specific types of inhibitory neurons and transplant them in an attempt to find the specific cell type responsible.