Voronin L L, Kudrashov I E, Skrebitskiĭ V G, Uvarov V G, Sharonova I N
Neirofiziologiia. 1977;9(2):124-34.
The work was aimed at recording in the hippocampus of unanesthetized rabbits changes in the EEG evoked by a single afferent spike. Extracellular focal activity was summarized by a computer triggered by spontaneous single unit discharges from a contralateral homotopic hippocampal point. No stable signal was revealed consistent with characteristics of EEG evoked by a unit discharge. Discharges of presumed Shafter collaterals were recorded at CA1 in two cases. After summation of focal activity recorded by the same microelectrode negative of 40-60 micronV amplitude were seen when the computer was triggered by these discharges. Such waves are supposed to be evoked by single spikes. Evoked potentials were recorded at the level of Shaffer collaterals (CA1) and mossy fibres (CA3) layers. In most cases the dependence of the evoked potential amplitudes on the current strength was not smooth but stepwise at nearthreshold stimulation. "Minimal" evoked potentials corresponding to the first step (40-80 micronV) are supposed to be produced by impulses in a single afferent fibres. No long-lasting posttetanic potentiation of "minimal" evoked potentials produced by the Shaffer collateral synapses was found. "Minimal" evoked potentials after mossy fibres stimulation underwent prominent potentiation. These data are consistent with the hypothesis of synaptic localization of the mechanisms of the long-lasting hippocampal posttetanic potentiation.
该研究旨在记录未麻醉家兔海马中单个传入冲动诱发的脑电图（EEG）变化。通过对来自对侧同位海马点的自发单个单位放电触发的计算机来汇总细胞外局部活动。未发现与单位放电诱发的EEG特征一致的稳定信号。在两例中记录到了假定的沙弗侧支在CA1区的放电。当计算机由这些放电触发时，对同一微电极记录的局部活动进行求和后，可看到幅度为40 - 60微伏的负波。这种波被认为是由单个冲动诱发的。在沙弗侧支（CA1）和苔藓纤维（CA3）层记录到了诱发电位。在大多数情况下，在接近阈值刺激时，诱发电位幅度对电流强度的依赖性并非平滑，而是呈阶梯状。对应于第一步（40 - 80微伏）的“最小”诱发电位被认为是由单个传入纤维中的冲动产生的。未发现沙弗侧支突触产生的“最小”诱发电位有长期的强直后增强。苔藓纤维刺激后的“最小”诱发电位出现了显著的增强。这些数据与海马长期强直后增强机制的突触定位假说一致。
