Neuroscientists have replaced half of the cells in a mouse's brain with human cells and produced a smarter mouse. Researchers left the neurons that do a mouse's thinking alone, but injected the animal’s brain with human glial cells (from a human fetus). The human glial cells then crowded out the mouse's glial cells. Treated mice performed better than normal ones on a slew of intelligence tests and showed improved memory, New Scientist reports. Researchers are hopeful that the results may translate into applications for treating human brain diseases like multiple sclerosis, which is thought to be caused by a defect in neuron support cells.
The goal, though is not to create brainy mice. The hope is to open up new ways to understand human brain diseases and develop therapies for them, said Dr. Steven Goldman, chairman of neurology at the University of Rochester, in New York according to the report. Human brains have different types of cells. Neurons are considered the workhorses, sending electrical and chemical signals to each other. Glial cells are seen as "support" cells that help transfer information among neurons.
But the relative size of glial cells in the human brain is bigger compared to non-primate animals. Humans also have more of them, and greater diversity in them, Goldman said. It has been thought that the evolution of glial cells may have been important to allowing humans to become as smart as they are.
The new findings, which appear in the March 7 issue of the journal Cell Stem Cell, support that theory.