Sik A, Penttonen M, Buzsáki G
Center for Molecular and Behavioral Neuroscience, Rutgers, State University of New Jersey, Newark 07102, USA.
Eur J Neurosci. 1997 Mar;9(3):573-88. doi: 10.1111/j.1460-9568.1997.tb01634.x.
Interneurons in the dentate area were characterized physiologically and filled with biocytin in urethane-anaesthetized rats. On the basis of axonal targets the following groups could be distinguished. (i) Large multipolar interneurons with spiny dendrites in the deep hilar region densely innervated the outer molecular layer and contacted both granule cells and parvalbumin-positive neurons (hilar interneuron with perforant pathway-associated axon terminals; HIPP cells). (ii) A pyramidal-shaped neuron with a cell body located in the subgranular layer innervated mostly the inner molecular layer and the granule cell layer (hilar interneuron with commissural-associational pathway-associated axon terminals; HICAP cell). It contacted both granule cells and interneurons. Axon collaterals of HIPP and HICAP neurons covered virtually the entire septo-temporal extent of the dorsal dentate gyrus. (iii) Calbindin-immunoreactive neurons with horizontal dendrites in stratum oriens of the CA3c region gave rise to a rich axon arbor in strata oriens, pyramidale and radiatum and innervated almost the entire extent of the dorsal hippocampus, with some collaterals entering the subicular area (putative trilaminar cell). (iv) Hilar basket cells innervated mostly the granule cell layer and to some extent the inner molecular layer and the CA3c pyramidal layer. HIPP and trilaminar interneurons could be antidromically activated by stimulation of the fimbria. Only the HICAP cells could be monosynaptically discharged by the perforant path input. All interneurons examined showed phase-locked activity to the extracellularly recorded theta/gamma oscillations or to irregular dentate electroencephalogram spikes. These observations indicate that the interconnected interneuronal system plays a critical role in coordinating population of the dentate gyrus and Ammon's hom.
在乌拉坦麻醉的大鼠中，对齿状区的中间神经元进行了生理学特征分析，并使用生物胞素进行填充。根据轴突靶点可区分出以下几组。(i) 深门区具有棘状树突的大型多极中间神经元密集支配外分子层，并与颗粒细胞和小白蛋白阳性神经元接触（具有穿通通路相关轴突终末的门区中间神经元；HIPP细胞）。(ii) 细胞体位于颗粒下层的锥体形神经元主要支配内分子层和颗粒细胞层（具有连合-联合通路相关轴突终末的门区中间神经元；HICAP细胞）。它与颗粒细胞和中间神经元都有接触。HIPP和HICAP神经元的轴突侧支几乎覆盖了背侧齿状回的整个隔-颞范围。(iii) CA3c区海马下托层中具有水平树突的钙结合蛋白免疫反应性神经元在海马下托层、锥体层和辐射层形成丰富的轴突分支，并支配背侧海马的几乎整个范围，一些侧支进入下托区（假定的三层细胞）。(iv) 门区篮状细胞主要支配颗粒细胞层，在一定程度上支配内分子层和CA3c锥体层。刺激穹窿可逆向激活HIPP和三层中间神经元。只有HICAP细胞可被穿通路径输入单突触放电。所有检查的中间神经元对细胞外记录的θ/γ振荡或不规则的齿状脑电图尖峰均表现出锁相活动。这些观察结果表明，相互连接的中间神经元系统在协调齿状回和海马结构的神经元群体方面起着关键作用。
