Imagine you are sitting on the couch in your living room reading. You do it almost every night. But then, suddenly, when you look up you notice this time something is different. Your favorite picture hanging on the wall is tilted ever so slightly. In a study involving epilepsy patients, National Institutes of Health scientists discovered how a set of high frequency brain waves may help us spot these kinds of differences between the past and the present.
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The experiment began when the patients were shown and asked to memorize a series of four natural scenes displayed on a computer screen. For example, one of the scenes was of a brown bicycle leaning upright on a kickstand in front of a green bush. A few seconds later they were shown a new set of images and asked whether they recognized the scene or noticed something different.
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Meanwhile, electrical recordings uncovered differences in brain wave activity between the times the patients successfully remembered repeat scenes and the times they spotted changes to a scene.
“High frequency waves of neural activity appear to carry an error message when we see something that does not match our expectations, while the lower frequency waves may be updating our memories,” [said researcher Kareem Zaghloul.]