Comparison of the Amplitude/Intensity Function of the Auditory Evoked N1m and N1 Components

This study compared the intensity dependence of the auditory evoked N1 and N1m components in 10 healthy subjects. The evoked responses were recorded simultaneously at 33 channels for the auditory evoked potentials (AEP) and with a 37-channel magnetometer for the auditory evoked fields (AEF). They were satisfactorily modeled by a tangential and a radial dipole per hemisphere for the N1 component and a tangential dipole in the left hemisphere for the N1m component. The tangential dipoles showed different dipole characteristics. The amplitude of the AEP rose significantly with increasing stimulus intensity whereas the amplitudes of the AEF tended to plateau between the highest intensities. The magnetic dipole shifted to the surface of the skull with higher stimulus intensity whereas the electric tangential dipole moved to the center of the skull. The latencies decreased with increasing stimulus intensity.

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