Dipole localization of P300 and normal aging.

At present, our understanding of how normal aging affects in vivo brain function is rudimentary. Therefore, the aim of the present study was to investigate age effects on auditory P300 topography. A recently developed dipole source model for P300 distinguishes overlapping P300 subcomponents and enhances reliability as well as validity of the measurement. 67 healthy subjects were examined using the P300 dipole model in addition to the scalp data measurement. The results show that P300 subcomponents reflect functionally different processes concerning age changes of P300 activities. Temporo-parietal P300 is smaller in older subjects, whereas frontal P300 is not attenuated. Age affected both P300 subcomponents' latencies. Therefore, the functionally different alteration of P300 subcomponents might be the reason for P300 topography changes with the P300 maximum more frontally in older age.