New memory study records the activation（n.激活） of human brain cells deep inside the living brain.
The mystery of what happens in our brains when we remember something is fascinating not only from a scientific perspective but also because the experience of recall can be so, well, memorable. Thinking backwards we become sensory（adj.感官的）time travelers; recalling sights, sounds, events, emotions - all in the blink of an eye. But what happens in our brains when we travel backwards?
For years scientists have told a story that goes roughly like this: when we experience something - say riding a bicycle for the first time - a network of neurons in the brain are activated. Then, later on, when we recall that first experience, that same network, or something like it, is activated again.
There is some roundabout（adj.迂回的，间接的） evidence that this is exactly what is going on, but nothing direct. That is, until now. A US and Israeli research group have provided the strongest evidence so far that this story is accurate by recording individual neurons inside the living human brain. One of the authors of the study, Dr. Itzhak Fried, describes it like this: "In a way then, reliving past experience in our memory is the resurrection（n.复苏）of neuronal activity from the past".
