健康受试者脑磁图M100发生源大脑半球空间位置差异的研究

目的研究健康受试者脑磁图脑诱发磁场发生源大脑半球空间位置差异。方法对31例健康受试者(男27例,女4例)分别给予左、右耳纯音刺激,刺激强度为90dB,频率为2kHz,刺激间隔1s,持续时间8ms,记录脑听觉诱发磁反应(AEFs)。结果AEFs的主要波峰为M100,位于双侧大脑半球颞横回,两侧ECD位置由头坐标系统中的X、Y、Z轴表示,结果显示给予左耳纯音刺激,ECD在左、右侧大脑半球X、Z轴无显著性差异(P>0.05),ECD在左、右侧大脑半球Y轴有显著性差异(P<0.05),给予右耳纯音刺激,ECD在左、右侧大脑半球X、Z轴无显著性差异(P>0.05),ECD在左、右侧大脑半球Y轴有显著性差异(P<0.05)。结论健康青年人对纯音刺激的诱发磁反应左、右侧半球反应位置在Y轴存在显著性差异,M100位置均在Y轴显示不对称,即左侧M100位置位于颞横回偏后,右侧M100位置位于颞横回偏前。

The left and right hemisphere's dipole position difference of M100 in healthy subjects measured by magnetoencephalography

Objective To study the left and right hemisphere's dipole position difference of M100 in healthy subjects measured by magnetoencephalography. Methods Thirty-one healthy subjects were examined by 306-channel whole-scalp magnetoencephalograhpy and 1.5T MR scanner. The subjects included 27 males and 4 females, aged from 14 to 72 years, average 44 years. The pure tone stimuli were given to the left and right ears respectively in all subjects with the intensity of 90 dB (sound pressure level, SPL), and frequency of 2 kHz, the inter-stimulus interval (ISI) was 1 s and the pure tone lasted 8 ms.The location of the primary auditory evoked was recorded by the MEG and observed after superimposing the MEG data on MRI. Results The main evoked peak of the auditory evoked fields was M100 (M100 was the auditory evoked responses occurred at about 100 ms after the auditory stimuli), the equivalent current dipole (ECD) was located at bilateral transverse temporal gyri, the location of the ECD represented by X, Y, Z axial in coordinate system. The results were as follows: there was no significant differences in X-axial and Z-axial in left and right hemisphere of the ECD (P>0.05) after given the left ear stimuli, there was significant differences in Y-axial in left and right hemisphere of the ECD (P<0.05). The dipole location in right was more forward than the left's; there was no significant differences in X-axial and Z-axial in left and right hemisphere of the ECD (P>0.05) after given the right ear stimuli, there was significant differences in Y-axial in left and right hemisphere of the ECD (P<0.05). The dipole location in right was more forward than the left's. Conclusion There are significant differences in Y-axial of the auditory evoked fields to pure tone in left and right hemisphere in healthy subjects. The right hemisphere M100 ECD location is anterior compared to the left hemisphere's.