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Analysis and Measurement of Neuromagnetic Fields Elicited by Stimulations of Sensory Nerves

感觉神经刺激引起的神经磁场的分析和测量

基本信息

批准号：
61550287
负责人：
KURIKI Shinya
金额：
$ 0.83万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

We have studied the neuromagnetic fields which are evoked by peripheral nerve and auditory stimulations. The measurement system we have developed consists of a mapping apparatus which includes a 2nd-order gradiometer and SQUID, a somatosensory and auditory stimulator, and a signal processor for averaging and amplitude and phase detection.In the somatosensory evoked fields (SEF), responses have two main peaks at 80 and 160 ms after the stimulus, while responses of the auditory evoked fields (AEF) have main peaks at 100 and 180 ms latencies. Estimation of parameters of a current-dipole source based on a least-squares fit to the mapping measured data has indicated that the dipole is located at somatosensory and auditory cortexes for the SEF and AEF, respectively. These locations agree well with MRI observation. The dipole moments are 5-30 nAm.In the steady state SEF responses to repeated stimuli, phase lag exhibits a linear dependence on the frequency of the stimuli. The linear relation gives three values of the time lag, two of which agree with the latencies of the main peaks in the transient response. The shortest time lag is attributed to the latency of the early component.In the AEFs with tone burst and short verbal sounds like/a/and/ka/, responses to the verbal sounds have similar peaks to the tone burst response. Estimated moments of the current-dipole sources for the tones and verbal sounds are nearly the same or larger in the right hemisphere than in the left hemisphere. There seems a slight difference in the location of the dipoles of the tones and verbal sounds in the left hemisphere.

我们研究了周围神经和听觉刺激所引起的神经磁场。该测量系统由二阶梯度计和SQUID、体感和听觉刺激器以及用于平均和幅度和相位检测的信号处理器组成。在体感诱发野中，反应在刺激后80ms和160ms有两个主峰，而听觉诱发野的反应在潜伏期100ms和180ms有主峰。基于最小二乘法对电流偶极子源参数的估计表明，对于SEF和AEF，偶极子分别位于体感皮质和听觉皮质。这些部位与MRI观察结果吻合较好。偶极矩为5-30nM。在稳态SEF对重复刺激的响应中，相位滞后与刺激频率呈线性关系。线性关系给出了三个时滞值，其中两个与瞬变响应中主峰的潜伏期一致。最短的时延归因于早期成分的潜伏期，在具有短语音(如/a/和/ka/)的短声时，对语音的反应具有与短声反应相似的峰值。音调和语音的电流偶极子源的估计矩在右半球几乎与左半球相同或更大。在左半球，声调和语言声音的偶极子位置似乎略有不同。