This press release from Princeton describes some research into what happens in the brain during the act of remembering. Volunteers were shown a series of pictures and then asked to remember them; while they were recalling the images, their brains were scanned and pattern-recognition software applied to the brain scans. Researchers found that the patterns of brain activation during recall tended to move toward the same pattern as when the images were first viewed. Furthermore, the researchers could identify patterns that corresponded to a particular type of object and could watch a participant’s brain moving toward that pattern and thus identify what the participant was about to recall, before the participant actually remembered it.
This seems relevant to the idea that one way to remember something is to put yourself back into the context in which you knew it in the first place, like when you forget what you were going to say and run back over what you were thinking of at the time. And maybe this has something to do with why smells or sounds can be so powerfully evocative of times past; the sensual cues to a particular environment seem to pull a whole train of related memories with them sometimes. It also makes me think about the difference between an experience and the memory of the experience. There are memories that I would give a lot to be able to go back and relive, but no matter how many details you can recall and how much you can place yourself back in the scene, it’s never the same thing as actually being there. Once I dreamed that you could connect some kind of gadget to your head with wires and then view your memories on a TV screen. Rationally it might not make any sense, but it sure was a compelling dream.