New research from the University of Pennsylvania has unveiled distinct gamma brainwave patterns associated with memory formation and recall:
Patients volunteered to study lists of words which they were then asked to recall at a later time. When asked to recall the studied words, participants recalled some number of correct items and also made a small number of errors, recalling words that had not appeared on the target list.
While patients performed the memory game, scientists observed electrical activity in their brains to determine whether specific brain waves were associated with successfully storing and retrieving memories. Researchers found that a fast brain wave, known as the gamma rhythm, increased when participants studied a word that they would later recall. The same gamma waves, whose voltage rises and fall between 50 and 100 times per second, also increased in the half-second prior to participants correctly recalling an item.
These analyses revealed that the same pattern of gamma band oscillatory activity in the hippocampus, prefrontal cortex and left temporal lobe that predicts successful memory formation also re-emerged at retrieval, distinguishing correct from incorrect responses, said Per B. Sederberg, lead author and former Penn neuroscientist now performing post-doctoral research at Princeton University. The timing of these oscillatory effects suggests that self-cued memory retrieval initiates in the hippocampus and then spreads to the cortex. Thus, retrieval of true as compared with false memories induces a distinct pattern of gamma oscillations, possibly reflecting recollection of contextual information associated with past experience.
These kinds of advancements in our understanding of memory will be incredibly useful in diagnosing and alleviating neurological problems from epilepsy to schizophrenia.
Here is the full paper: http://memory.psych.upenn.edu/publications/files/SedeEtal07b.pdf
For more on recent work on gamma waves, check out this lecture by Robert Knight: http://www.mindupdate.com/?p=63
Thanks to Tyler on the forums for finding this.