Nevalainen P, Ramstad R, Isotalo E, Haapanen M-L, Lauronen L
BioMag Laboratory, Helsinki University Central Hospital, P.O. Box 340, FIN-00029 HUS, Finland.
Clin Neurophysiol. 2006 Sep;117(9):2007-15. doi: 10.1016/j.clinph.2006.05.019. Epub 2006 Jul 20.
To characterise the activation of the contra- and ipsilateral primary somatosensory cortex (SI) after tactile stimulation of the face.
Trigeminal somatosensory evoked magnetic fields (TSEFs) were recorded after tactile stimulation of the lower lip, cheek, chin and forehead in 11 healthy subjects. The responses were determined visually from the waveforms and modelled with equivalent current dipoles (ECDs).
Contralateral SI responses were evoked in all subjects after lip stimulation, and in 91% and 64% after right and left cheek, 73% and 82% after chin and 64% and 27% after forehead stimulation. The responses usually showed an early double-peak wave pattern, the underlying sources localising to the SI. In addition, altogether 37 ipsilateral SI responses were evoked in eight subjects. Fourteen of these responses were amenable to ECD modelling and localised to ipsilateral SI.
Tactile stimulation of the lip area reliably activates the contralateral SI in normal subjects, but the success rate for other trigeminal areas is lower. Ipsilateral responses can be present after stimulation of any of the trigeminal branches in normal subjects.
Recording of TSEFs after tactile stimulation of particularly the lip area provides a non-invasive technique to study the function of the trigeminal nerve.
描述面部触觉刺激后对侧和同侧初级躯体感觉皮层（SI）的激活情况。
对11名健康受试者的下唇、脸颊、下巴和前额进行触觉刺激后，记录三叉神经体感诱发磁场（TSEF）。通过波形直观确定反应，并使用等效电流偶极子（ECD）进行建模。
所有受试者在唇部刺激后均诱发对侧SI反应，右侧和左侧脸颊刺激后分别有91%和64%的受试者出现反应，下巴刺激后分别为73%和82%，前额刺激后分别为64%和27%。反应通常呈现早期双峰波形，其潜在来源定位于SI。此外，8名受试者共诱发了37次同侧SI反应。其中14次反应适合ECD建模，并定位于同侧SI。
在正常受试者中，唇部区域的触觉刺激可靠地激活对侧SI，但其他三叉神经区域的成功率较低。正常受试者在三叉神经任何分支刺激后均可出现同侧反应。
特别是对唇部区域进行触觉刺激后记录TSEF，为研究三叉神经功能提供了一种非侵入性技术。
