Mind's ear in a musician: where and when in the brain.

The temporospatial pattern of brain activity during auditory imagery was studied using magnetoencephalography. Trained musicians were presented with visual notes and instructed to imagine the corresponding sounds. Brain activity specific to the auditory imagery task was observed, first as enhanced activity of left and right occipital areas (average onset 120-150 ms after the onset of the visual stimulus) and then spreading to the midline parietal cortex (precuneus) and to such extraoccipital areas that were not activated during the visual control condition (e.g., the left temporal auditory association cortex and the left and right premotor cortices). The latest activations, with average onset latencies of 270-400 ms clearly separate from the earliest ones, occurred in the left sensorimotor cortex and the right inferotemporal visual association cortex. These data imply a complex temporospatial activation sequence of multiple cortical areas when musicians recall firmly established audiovisual associations.