title: Hemispheric asymmetry of the auditory evoked N100m response in relation to the crossing point between the central sulcus and Sylvian fissure.
abstract: The positions of the bilateral N100m sources of the auditory evoked magnetic 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 (SEFs), 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) between 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 hemispheric 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 functional asymmetry of the human temporal lobe and possible source extension of the AEF-N100m beyond the Heschl gyrus over the planum temporale.
authors.affiliation: Department of Neurosurgery, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ohtomo
authors.forename: N
authors.initials: N
authors.lastname: Nakasato
authors.forename: A
authors.initials: A
authors.lastname: Kanno
authors.forename: K
authors.initials: K
authors.lastname: Hatanaka
authors.forename: R
authors.initials: R
authors.lastname: Shirane
authors.forename: K
authors.initials: K
authors.lastname: Mizoi
authors.forename: T
authors.initials: T
authors.lastname: Yoshimoto
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D002535:Cerebral Aqueduct / Q000502:physiology*; D004558:Electric Stimulation; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008475:Median Nerve / Q000502:physiology; D008875:Middle Aged