Relative timing of neuronal activity in distinct temporal lobe areas during a recognition memory task for words.

Nine neurologically normal volunteers engaged in a recognition memory task for visually presented words while the magnetic flux normal to the scalp surface was measured with a whole-head neuromagnetometer. The relative timing of activity occurring during the task in different brain areas was determined. Occipital lobe areas became active first, followed by basal temporal areas. Temporoparietal and medial temporal areas became active next, during later portions of the recorded epoch, and appeared to activate in concert. Except for the occipital lobe, activity was predominantly in the left hemisphere. This pattern was consistent across participants. Results suggest that MEG, in capturing temporal as well as spatial aspects of brain activity, has a promising role as an adjunct to other functional imaging modalities.