Durations of extended mental rehearsals are remarkably reproducible in higher level human performances.

It has been extremely difficult to quantify temporal aspects of higher level human brain function. We have found that mental rehearsals of musical performance of several minutes duration provide such a measure in that they can be highly reproducible, varying to less than 1%. These remarkable results pose fundamental neurophysiological problems. It is necessary to understand the underlying neuronal bases for this accuracy in the spatial-temporal activity of billions of neurons over minutes without sensory input. Further, they present a powerful constraint on neuronal models of brain function. Such highly reproducible (in duration) mental rehearsals might be used in conjunction with multielectrode EEG recordings to look for reproducible spatial-temporal patterns. Further, we suggest that our results may provide an extremely useful behavioural correlate for high level performance.