A human glial cell (green) among normal mouse glial cells (red). The human cell is larger, sends out more fibers and has more connections than do mouse cells. Mice with this type of human cell implanted in their brains perform better on learning and memory tests than do typical mice.
For more than a century, neurons have been the superstars of the brain. Their less glamorous partners, glial cells, can't send electric signals, and so they've been mostly ignored. Now scientists have injected some human glial cells into the brains of newborn mice. When the mice grew up, they were faster learners. The study, published Thursday in Cell Stem Cell by Maiken Nedergaard, M.D., D.M.Sc. and Dr. Steven Goldman, M.D., Ph.D., not only introduces a new tool to study the mechanisms of the human brain, it supports the hypothesis that glial cells - and not just neurons - play an important role in learning.
Today, glial research and Dr. Goldman were featured on National Public Radio (NPR) speaking about the glial research that is outlined in this current publication. I can't tell the differences between a neuron from a bird or a mouse or a primate or a human,
says Goldman, glial cells are easy to tell apart. Human glial cells - human astrocytes - are much larger than those of lower species. They have more fibers and they send those fibers out over greater distances.
In collaboration with the Nedergaard Lab, newborn mice had some human glial cells injected into their brains. The mice grew up, and so did the human glial cells. The cells spread through the mouse brain, integrating perfectly with mouse neurons and, in some areas, outnumbering their mouse counterparts. All the while Goldman says the glial cells maintained their human characteristics.