Non-invasive measurements of sensory nerve and cortical responses to skin stimulation : Integration of EEG,MEG and fMRI

1.研制了3点独立控制的吹气刺激器，用于诱发感觉神经动作电位和体感诱发电位.我们研制了三点振动刺激器，用于研究体感诱发场与体感系统对频率、持续时间和强度的感知。我们用高速摄像机观察了空气刺激后皮肤的位移，这些位移与感觉阈值和幅度估计相关。我们可视化了一个沿着正中神经移动的四极杆，并对肘部的作用场进行了多通道测量。在周围神经病变，我们发现了一个特殊的振荡模式的电诱发的行动领域或远端的病变部位。我们利用Hodgikin-Huxley方程对振荡进行了计算机模拟，发现Na电导的增加与振荡有关.我们测量了三叉神经后的磁场 ...更多信息 l刺激，并表明皮层下产生的领域是强大的，足以检测到外面的头。我们在清醒和睡眠期间测量N20 m初级反应，随后进行数字高通（>300 Hz）和低通（>300 Hz）滤波。高频振荡（HFO）的估计来源是非常接近N20 m的区域3b。在睡眠期间，HFO的振幅显着减少，而N20 m振幅表现出适度的增量。HFO和N20 m在清醒-睡眠周期期间的这种相互关系表明它们代表相反的发生器基质。我们推测HFO代表第4层GABA能抑制性中间神经元的局部活性，其在动物实验中已被证明对丘脑-皮层输入以高频（600-900 Hz）短持续时间尖峰脉冲群单突触响应。另一方面，潜在的N20 m代表锥体神经元的活动，其接收来自丘脑的单突触兴奋性输入以及来自中间神经元的前馈抑制。这一假设得到了我们最近在清醒期间操纵N20 m振幅的实验的进一步支持; HFO和N20 m之间的相互关系不仅在清醒-睡眠周期期间而且在清醒期间保持。少

1. We developed 3 point air-puff stimulators which can be controlled independently for eliciting sensory nerve action potentials and somatosensory evoked potentials.2. We developed 3 point vibratory stimulators for studying somatosensory evoked fields associated with perception of frequency, duration and intensity in the somatosensory system.3. We visualized displacements of the skin following air-puff stimulation with a high speed camera which were correlated with a sensory threshold and magnitude estimations.4. We visualized a moving quadrupole along the median nerve with multi-chnnel measurements of action fields over the elbow.5. In peripheral nerve lesions, we found a peculiar oscillation pattern of electrically evoked action fields at or distal to the lesion sites. We performed a computer simulation for the oscillation using the Hodgikin-Huxley equations and found that the increase of Na conductance was related to the oscillation.6. We measured magnetic fields following trigemina … More l stimulation from the decorticated piglets and showed that the subcortically generated fields are strong enough to the detectable outside the head.7. We measured N20m primary response during wakefulness and sleep with subsequent digital high-pass (>300 Hz) and low-pass (>300 Hz) filtering. The estimated source for the high-frequency oscillations (HFOs) was the area 3b very close to that for the N20m. During sleep, the HFOs showed a dramatic diminution in amplitude while the N20m amplitude exhibited a moderate increment. This reciprocal relation between the HFOs and the N20m during a wake-sleep cycle suggests that they represent opposing generator substrates. We speculate that the HFOs represent a localized activity of the GABAergic inhibitory interneurons of layr 4, which have been shown in animal experiments to respond monosynaptically to thalamo-cortical input with a high-frequency (600-900 Hz) burst of short duration spikes. On the other hand, the underlying N20m represents activity of pyramidal neurons which receive monosynaptic excitatory input from the thalamus as well as a feed-forward inhibition from the interneurons. This hypothesis has been further supported by our recent experiments manipulating the amplitude of N20m during wakefulness ; the reciprocal relation between HFOs and N20m hold not only during a wake-sleep cycle but also during wakefulness. Less