Scientists have created hybrid mice that can use rat neurons to smell, showcasing potential new methods for brain disease research.have engineered mice with part-rat, part-mouse brains that allow them to smell as rats do. This breakthrough demonstrates the brain’s capacity to integrate foreign cells and could advance our understanding of and ability to treat human brain diseases.
It is the first time that an animal has been able to use the sensory apparatus of another to sense and respond accurately to the world and is one indication of how flexible the brain can be in integrating outside brain cells. “We have beautiful models of cells in dishes and 3D cultures called organoids and they both have their advantages,” Baldwin says, “But none of them allow you to determine if the cells are really functioning at the highest level.”
“These experiments have told us that we are somewhat limited in when and how we can add brain cells to an existing brain,” Baldwin says. “If the brain has developed to a certain point, the transplanted cells don’t necessarily wire together appropriately.” “You could see rat cells throughout almost the entire mouse brain, which was fairly surprising to us,” Baldwin says. “It tells us that there are few barriers to insertion, suggesting that many kinds of mouse neurons can be replaced by a similar rat neuron.”