Mechanism of thalamo -cortical projection and intracerebral association

以正常人和猫为实验对象，研究了体感觉通路中丘脑-皮质投射和脑内关联系统的作用机制。在正常志愿者和猫的头皮、颅骨、硬脑膜、皮层上和皮层内记录皮层和皮层下的体感诱发电位（SEPs），以评估体感通路和初级感觉皮层（SI）的功能。睡眠期正常对照头皮皮层电位图显示，睡眠期N20、P20、P22、P23和N24皮层成分在睡眠II和III/IV期出现形态变化和潜伏期峰延迟，在快速眼动睡眠时恢复到初始形态和潜伏期峰。这些发现表明，非快速眼动睡眠影响皮层sep的起源，这可能与感觉皮层的突触功能有关。记录猫的头皮、颅骨、硬脑膜、皮质上和皮质内的皮质和皮质内sep。皮层上、皮层内和头皮上的电位在形态和峰潜伏期上存在本质差异。此外，在皮层上间隔3至5毫米的内侧、中央和外侧SI区记录的皮质sep在每个电极上的形态和潜伏期完全不同。这些发现表明，来自丘脑的体感通路不仅投射到SI区，而且投射到额叶和顶叶皮层。在猫的两个次级感觉皮层（SII区域）记录皮层sep是不可能的。在电刺激桡神经之前、期间和之后，对猫的SI、运动和顶叶皮层的神经递质进行了分析。电刺激桡神经使对侧第一感觉区和运动区乙酰胆碱释放增加。胆碱能传递可能参与皮层SEP产生的机制。

The mechanism of thalamo-cortical projection and intracerebral association system in the somatosensory pathways was studied in normal volunteers and cats. Cortical and subcortical somatosensory evoked potentials (SEPs) were recorded from the scalp, skull, dura mater, supra-and intra-cortex to evaluate the function of somatosensory pathways and primary sensory cortex (SI) in normal volunteers and cats. Topography of cortical SEPs over the scalp in normal controls during sleep stage revealed that cortical components (N20, P20, P22, P23 and N24) showed morphological changes and delayed peak latencies during sleep stage II and III/IV, and returned to the initial morphologies and peak latencies during REM sleep. These findings suggest that NREM sleep affects the origins of cortical SEPs which could be related to the synaptic function in the sensory cortex.Cortical and intracortical SEPs were recorded from the scalp, skull, dura mater, supra- and intra-cortex in cats. Morphologies and peak latencies of SEPs were essentially different between supra- and intra-cortical SEPs and scalp SEPs. Furthermore, cortical SEPs recorded from the medial, central and lateral SI areas with 3 to 5 mm intervals over the cortex were quite different morphologies and latencies in each electrode. These findings suggest that somatosensory pathways from the thalamus project not only to the SI areas but to frontal and parietal cortices.It is impossible to record cortical SEPs from both secondary sensory cortices (SII areas) in the cats.Neurotransmitters from the SI, motor and parietal cortices of the cats were analysed before, during and after the electrical stimulation of the radial nerve. The electrical stimulation of the radial nerve increased the acetylcholine release in the contralateral primary sensory area (SI) and motor area. Cholinergic transmission may be involved in the mechanism of cortical SEP generation.