AUDITORY-EVOKED OFF-RESPONSE - ITS SOURCE DISTRIBUTION IS DIFFERENT FROM THAT OF ON-RESPONSE

OFFSET auditory responses were investigated by electroencephalography mainly in the 1970s, but since then no particular attention has been p aid to them. Among the studies using magnetoencephalography (MEG) devi ces there are, to our knowledge, only three studies of the auditory of f-response, and no significant variance has ever been observed between the source locations of on- and off-responses elicited from pure tone s. We measured auditory evoked magnetic fields (AEFs) to various frequ ency pure tone stimulation in 5 healthy subjects with a 122-channel he lmet-shaped magnetometer, and compared the distributions of the source locations of auditory N100m-Off (magnetic off-response around 100 ms) with those of N100m-On. Their spatial distributions were quite close to each other, and yet they were significantly different. (C) 1998 Rap id Science Ltd.