How does memory work? What changes in the brain when we learn something?
We don't know for sure. But two outstanding
papers have just provided an important piece of the puzzle, using a truly amazing technique which allowed them to examine the brain of a living, breathing mouse under the microscope.
The approach uses mice genetically engineered such that some of their neurons contain yellow fluorescent protein (YFP). You may have already heard of the cute glowing mice who have green fluorescent protein (GFP) in all their cells. In these YFP-H mice, only some of their neurons are fluorescent.
Two-photon microscopy uses a focused laser beam to image fluorescent tissue. The authors of these papers were able to image the brain (the cortex) after surgically thinning - but not penetrating - the mice's skulls. The bone over the brain area in question was removed until it was just 20 ...
