Electrophysiological correlates of temporal and spatial information processing.

In order to study the neurophysiological correlates of working memory for different types of information, event-related brain potentials (ERPs) were recorded during a visual spatial and visual as well as auditory duration memory tasks. From stimulus onset to 500 ms ERPs were distinguishable by allocation to visual or auditory modality. From 500 to 2000 ms after stimulus onset, the spatial task generated a parieto-occipital focused negative slow wave, while corresponding ERPs of the temporal task showed a negative slow wave with frontolateral focus. From 1200 to 5500 ms a large positivity was found for the auditory temporal task and for good performers of the visual temporal task. The data suggest a distinction of three processing phases: modality-specific encoding, information-specific encoding and retention in conjunction with modality-specific inhibition processes.