S. Ohtomo et al., HEMISPHERIC-ASYMMETRY OF THE AUDITORY-EVOKED N100M RESPONSE IN RELATION TO THE CROSSING POINT BETWEEN THE CENTRAL SULCUS AND SYLVIAN FISSURE, Electroencephalography and clinical neurophysiology. Evoked potentials, 108(3), 1998, pp. 219-225
The positions of the bilateral N100m sources of the auditory evoked ma
gnetic fields (AEFs) were measured in relation to the central sulcus (
CS) using an MRI-linked whole head magnetoencephalography system in 20
right-handed normal male subjects. The location of the N20m source of
the median nerve-stimulated somatosensory evoked magnetic fields (SEF
s), in the left hemisphere was 3.9 +/- 5.4 mm (mean +/- SD) posterior
to that in the right hemisphere (P < 0.005). The crossing point (CP) b
etween the CS and Sylvian fissure in the left hemisphere was 4.3 +/- 4
.8 mm posterior to that in the right hemisphere (P < 0.001). The N100m
sources were posterior to the CP in both hemispheres. The left hemisp
heric N100m source was 9.4 +/- 6.4 mm posterior to that on the right (
P < 0.0001) in absolute position. The relative distance between CP and
the N100m source was 22.7 +/- 8.5 mm in the left hemisphere and 17.7
+/- 5.3 mm in the right hemisphere (P < 0.01). Comparison of positions
of the AEF sources and the CS as defined by the SEF demonstrated func
tional asymmetry of the human temporal lobe and possible source extens
ion of the AEF-N100m beyond the Heschl gyrus over the planum temporale
. (C) 1998 Elsevier Science Ireland Ltd.