Functional and topographical differences between processing of spoken nouns which were remembered or which were forgotten were shown by means of EEG coherence analysis. Later recalled nouns were related with increased neuronal synchronization (􏰏 cooperation) between anterior and poster- ior brain regions regardless of presented word category (either concrete or abstract nouns). However, theta coherence exhibited topographical differences during encoding of concrete and abstract nouns whereby former were related with higher

short-range (mainly intrahemispheric), later with higher long- range (mainly interhemispheric) coherence. Thus, theta syn- chronization possibly is a general phenomenon always occur- ring if task demand increases and more ef®cient information processing is required. Measurement of EEG coherence yields new information about the neuronal interaction of involved brain regions during memory encoding of different word classes.