Shimazu K, Miyake Y, Fukatsu Y, Watanabe S
Department of Ophthalmology, Nagoya University School of Medicine, Aichi-ken, Japan.
Nippon Ganka Gakkai Zasshi. 1994 Nov;98(11):1071-8.
We analyzed current source density and multiple unit activity of area 17 of cats in response to transcorneal electrical stimuli to clarify the localization of the transmembrane current flows contributing to the generation of the electrically evoked response. The results of the current source density analysis were as follows. 1. Current sinks within 20 ms were observed in layers 4 and 6. 2. Current sinks corresponding to N3 (latency 35 ms) were detected in layers 4 and lower 3 and current sources were in the supragranular layers. 3. Current sinks with a latency of more than 40 ms were observed in the supragranular layers. Simultaneous multiple unit activity was present in cases 1 and 2. With increased stimulus frequency or double electrical stimuli, the current sinks corresponding to N3 were decreased. These findings indicate that N1 (latency 9 ms) and N2 (latency 20 ms) reflect near-field potentials generated by geniculocortical afferents in layers 4 and 6, and that N3 is a post-and polysynaptic component. In addition, it appears that dipoles consisting of cell bodies and apical dendrites of pyramidal cells in layer 3 generated by satellite cell in layer 4, play a major role in generating N3.
我们分析了猫17区的电流源密度和多单位活动，以响应经角膜电刺激，从而阐明对电诱发反应产生有贡献的跨膜电流流动的定位。电流源密度分析结果如下：1. 在第4层和第6层观察到20毫秒内的电流汇集。2. 在第4层和第3层下部检测到与N3（潜伏期35毫秒）相对应的电流汇集，电流源位于颗粒上层。3. 在颗粒上层观察到潜伏期超过40毫秒的电流汇集。在病例1和病例2中存在同步多单位活动。随着刺激频率增加或双电刺激，与N3相对应的电流汇集减少。这些发现表明，N1（潜伏期9毫秒）和N2（潜伏期20毫秒）反映了第4层和第6层中膝状体皮质传入神经产生的近场电位，并且N3是一个突触后和多突触成分。此外，似乎由第4层卫星细胞产生的第3层锥体细胞的细胞体和顶端树突组成的偶极在产生N3中起主要作用。
