Two separate frontal components in the N1 wave of the human auditory evoked response


  • François Perrin died on June 29, 1993. This study could not have been achieved without his fundamental methodological work on scalp current density analysis.

Address reprint requests to: M. H. Giard, INSERM-U280, 151 Cours Albert Thomas, 69003 Lyon, France.


Scalp current density analysis of the auditory evoked response to 1-kHz tone bursts delivered at various interstimulus intervals (ISIs) (from 1 s to 2 min in separate runs) shows that two different frontal components can be observed and functionally dissociated in the N1 time range: one is elicited for all ISIs, peaks at about 95 ms poststimulus, and has a full recovery time below 8 s; the second is elicited only by infrequent stimuli (ISIs > 4 s), peaks around 140 ms, and significantly increases in amplitude with increasing ISIs. The first component can be considered a new obligatory component in N1 elicited simultaneously with the responses in auditory cortex; the later component could correspond to the orienting Component III of Näätänen and Picton (1987).