For most humans, it may not be the most flattering idea to think of their brains as resembling that of a mouse.
But a new breed of “super mice” at Stanford University, featured in an article in the science publication Discover, are changing that perception. Scientists are studying them for ways to reverse brain damage.
Strengths and Weaknesses
The mice live in a carefully guarded facility, visited only by their keeper, neurobiologist Carla Shatz, and her exclusive laboratory team. These mice learn complex tasks with
amazing speed. They recover more quickly from brain injuries. And even with one eye removed, they beat other one-eyed mice in visual sensory tests.
However, the mice are not super in every way. The reason they are so carefully guarded is because their immune systems are incredibly fragile.
Shatz has bred them without certain crucial proteins needed for fighting off germs.
The Immunity Protein — Good or Bad?
This protein, called MHCI, is responsible for identifying and targeting infected cells within the body and signaling the immune system to get them out as soon as possible. But what is great for the body actually acts as a hindrance of sorts to the brain.
MHCI regulates neuroplasticity — the brain’s ability to adapt its circuitry throughout an organism’s life. If the organism’s growth happens normally, this is a good thing. But for those affected by trauma — be it an infection present in the mother during pregnancy, or a severe injury to the head — MHCI tells neurons in the adult brain to lie low and stabilize, rather than adapt to the situation.
Shatz described experiments with severing a laboratory animal’s eye after removing MHCI. The neurons went to work trying to work around the change, reorganizing themselves to create a replacement connection. It’s like the brain was saying to itself: “We don’t have an eye to get our information? Fine — we’ll figure out a different way.”
This might sound like a good thing and make you wonder why we need MHCI in our brains, at all. The reason is, simply, survival. Without MHCI, the brain might just keep trying all kinds of different reorganization patterns and not ever be able to resume normal operations.
But Shatz found that when MHCI gets too involved, other bad things can happen. In cases of disease or trauma to a fetus, it closes down certain key synapses (or connections) between the brain’s neurons, setting the stage for conditions like autism or schizophrenia. In older brains, MHCI expression is partly to blame for the effects of neurodegenerative diseases like Alzheimer’s and Parkinson’s, as well as the effects of stroke or spinal cord damage.
Not surprisingly, Carla Shatz’s motivation to study the brain’s biology comes from a very personal place. When she was in high school, her grandmother suffered a stroke that took away all her language or motor skills.
Motivated by the sad memory of those years, when her formerly brilliant grandmother could no longer function or communicate, she continues her work at Stanford in search of her personal golden chalice: a pill that would manipulate MHCI molecules or their receptors and enhance the brain’s aptitude to make a smart recovery from damage.
Shatz even dreams of a “plasticity pill” to restore the neural suppleness of stroke victims — and her latest experiments offer hope that it could someday come to pass.
People have called her crazy for expressing this hope; for Shatz, that’s nothing new. They were calling her crazy all the way back when she posited the presence of MHCI in the brain, at all…even after she proved it, the skepticism didn’t stop.
“But my parents gave me some advice when I was young,” Shatz told Discover. “They said, ‘Don’t worry about what other people think of you.’”
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