Scientists can now predict memory of an event before it even happens

Feb 27 2006

Scientists can now predict memory of an event before it even happens. A team at UCL (University College London) can now tell how well memory will serve us before we have seen what we will remember.

Scans of brain activity, published online in the journal Nature Neuroscience, indicate that the brain can actually get into the 'right frame of mind' to store new information and that we perform at our best if the brain is active not only at the moment we get new information but also in the seconds before.

Dr Leun Otten from UCL Psychology and the UCL Institute of Cognitive Neuroscience, who led the research project, said: "It sounds a bit like clairvoyance in the sense that we're able to predict whether someone will remember a word before they even see it. That's really new - scientists knew that brain activity changes as you store things into memory but now we have found brain activity that tells how well your memory will work in advance."

Two experiments were conducted to tap into long-term memory and arrive at the results. In the first, a symbol was presented on screen a few seconds before each word, telling the subjects what kind of decision to make about the following word. Participants either had to decide whether the word referred to something living, or whether the first and last letters of the word were in alphabetical order.

In the second experiment, the subjects had to imagine what the item looked like to decide whether it was taller than wide or vice versa. The cue before each word in this experiment told people whether the following word would be seen or heard. These tests were designed to make the subject think about different aspects of a word, including its meaning.

The participants' brains were scanned using an EEG (electroencephalogram) scanner which looks like a swimming cap covered with electrodes and records electrical brain activity on the scalp. The scanners, popular since the 1960s, are used in hospitals to detect epilepsy in people and are an important tool to show not just what bits of the brain are lighting up but also what triggers it to light up and when.

In this test, the important thing was to find out whether brain activity before an event has an impact on memory or whether, as was previously thought, it's just brain activity after an event that is important for memory. Without the timeline given by an EEG scanner such an analysis would not be possible.

Tests showed that the brain's electrical activity differed after the cue question and before the word was presented and this was linked to whether the subject would remember or forget the word in a later unexpected memory test. If the electrical activity maintained a high level over frontal parts of the scalp just before the word was shown, then it was likely that the subject would remember the word up to 50 minutes later - and after doing a series of other word tests. On the other hand, if the voltage was lower, the subjects were less likely to remember the word.

Dr Otten said: "It would be nice to know what brain regions are involved in this preparatory activity, and whether it can be used to help people who have difficulties remembering things. Unfortunately we aren't at that stage yet! What we do know though is that it might have something to do with trying to get into the right frame of mind to make a decision about a word's meaning. Staying alert between the cue and the word also appears to help. We are currently trying to find out more about this kind of brain activity and how it helps long-term memory."