摘要
目的:了解半视野图形刺激的视觉诱发磁场(visualevokedfield,VEF)反应中组成部分的时间和空间分布特点,并通过与MRI图像相叠加,了解各组成部分所对应偶极源的确切位置。方法:分别测试40名受试者对垂直左半侧视野的视觉诱发磁场反应,分析各组成部分的潜伏期及波幅,并通过磁源成像精确定位半视野图形刺激所引起视觉诱发磁场的位置。结果:左半视野刺激可在右侧半球引起较为明显的3期相复合波形,3种组成部分分别为M75,M100和M145,其中M100和M145的出现率均为100%,M75的出现率为72.5%。M75,M100和M1453种成分所对应的偶极均为单偶极模式。在磁场等高图上,3种成分偶极均位于右侧半球枕区。与MR图像叠加后,M75,M100和M1453种成分所对应的偶极亦均位于右侧枕叶,M100偶极指向由外向内,M75和M145偶极指向由内向外。其中M100偶极位于舌上回、楔下回、楔舌后回和舌下回等区域。M75偶极出现在包括舌上回、楔下回、舌下回、楔舌后回、楔上回和缘上回在内的区域。M145偶极可出现在舌上回、楔下回、楔上回、楔中回、舌下回。结论:左半视野刺激会在刺激野的对侧半球枕区引起单偶极模式的兴奋。图形刺激视觉诱发磁场反应中的M100兴奋主要由纹状皮质(Brodmann17区)的神经元产生,位于刺激野对侧半球枕区的距状裂底部后方。
AIM:To understand the temporal and spatial characteristics of the three components of normal volunteers' visual evoked field(VEF) response to left vertical half field stimulation and the location of corresponding dipoles overlapped on MRI. METHODS:The VEF response to left vertical half field was detected in 40 subjects.The latency and amplitude of every component were analyzed.The exact locations of the dipoles overlapped on MRI were detected. RESULTS:A typical three phase complex waveform response to left half field stimuli could be detected in the right brain hemisphere.The three components of the waveform were M75,M100 and M145.The former one were with the occurrence of 72.5%,and the two latter ones with the occurrence of 100%.The corresponding dipoles of the M75,M100 and M145 in response were single models.The isocontour maps indicated that the three dipoles were all positioned in the right hemisphere.After overlapped on MRI,the dipoles response to M75,M100 and M145 were located in the occipital lobe.The current direction was from the lateral to medial for the M100 dipole,and from the medial to lateral for the M75 and M145 dipoles.The M100 dipoles were identified at superior lingual gyrus,inferior cuneus gyrus,posterior cuneolingual gyrus and inferior lingula gyrus,the M75 dipoles at superior lingual gyrus,inferior cuneus gyrus,inferior lingual gyrus,posterior cuneolingual gyrus,inferior lingula gyrus and supramanginal gyrus,and the M145 dipoles were identified to be at superior lingual gyrus,inferior cuneus gyrus,superior cuneus gyrus,middle cuneus gyrus and inferior lingula gyrus. CONCLUSION:A single dipole pattern activation can be acquired over the occipital area contralateral to the stimulated half field.The dipole activation of M100 in VEF response to pattern reversal stimulation is mainly generated by the neurons in striate cortex contralateral to the stimulated side,which is at the lateral bottom of the calcarine fissure.The neural origins of M75 are mainly in the striate cortex and parastr
出处
《中国临床康复》
CSCD
2004年第10期1838-1840,T001,共4页
Chinese Journal of Clinical Rehabilitation
