How do we remember something? Neuroscientists speak of memory
engrams to describe the way in which traces of memory are stored
in our brains. A memory engram might respond to something
external, for example, the scent of a rose. But how do engrams
work? Is an engram just an intellectual concept? Or are engrams
a physical network of neurons in the brain? A new study
published in the journal Nature on March 23, 2012 suggests that
memories really do reside in specific brain cells, at least in
mice. Researchers from MIT and Stanford used optogenetics – a
combination of genetic and optical techniques in the lab, used
to control specific events in targeted cells – to scrutinize the
brains of special mice that had been genetically engineered for
their memory study. First, the researchers identified which
cells in the mice brains were active only when a mouse was
learning about a new environment. Then they determined which
genes were activated in those brain cells. Then they created
transgenic mice, artificially link