It has happened to us all at some point – a person looks familiar but you can't remember where on earth you met them. Now new research by neuroscientists in the states published in this week's edition of the journal Neuron suggests why – the memory does exist, but you just can't retrieve it.
Using functional MRI scanning, the scientists found that brain activity while remembering an event is very similar to when you first experienced it, even if you can't remember the details. But the researchers, led by Jeff Johnson, think that we could manage to access this missing details. So it could help us to boost our memory-power as we get older, and also help to shed light on vivid – but traumatic- memories that we may subconsciously forget.
Inside a brain scanner, volunteers were shown words and asked to do various tasks. For example, this included imagining how an artist would draw the object named by the word, thinking about how the object is used, or pronouncing the word backward in their minds.
Then twenty minutes later, the volunteers saw the words a second time, and were told to remember anything linked to them.
By comparing the initial patterns of brain activity with the later patterns, the researchers were able to link certain patterns of brain activity to the different activities. When a volunteer strongly recalled a word from a particular task, the pattern was very similar to the one generated during the task. Also, when they only weakly recalled what they'd thought of, they still produced a pattern recognisable as belonging to that particular task.
So the results suggest our memory is in there somewhere – we just need to work out how to get it out!