AGE-RELATED FUNCTIONAL DIFFERENCES BETWEEN AUDITORY CORTICES - A WHOLE-HEAD MEG STUDY

AUDITORY evoked magnetic fields (AEFs) were recorded from 10 healthy y ounger and 10 older subjects using a whole-head magnetometer. Two bloc ks of tone pips were presented to the left ear with constant inter-sti mulus intervals (ISIs) of 0.5 and 2.5 s. The amplitude of P50m, unlike that of N100m, was larger in the older subjects. In both groups, the peak latencies of P50m and N100m responses were significantly shorter over the contralateral than ipsilateral cortex. The interhemispheric l atency difference of N100m was significantly increased with age. These findings suggest that ageing delays signal processing in the ipsilate ral auditory cortex and that ageing affects consecutive AEFs in a diff erent manner.