McIntyre D C, Kelly M E, Staines W A
Department of Psychology, Institute of Neuroscience, Carleton University, Ottawa, Ontario, Canada.
J Comp Neurol. 1996 May 27;369(2):302-18. doi: 10.1002/(SICI)1096-9861(19960527)369:2<302::AID-CNE10>3.0.CO;2-J.
Because convulsive seizures develop very rapidly from kindling sites in the anterior perirhinal cortex, we studied perirhinal efferents by using the anterograde tracer Phaseolus vulgaris leucoagglutinin (PhAL). PhAL injections into the anterior perirhinal cortex labelled a prominent network of fibers within the frontal cortex that was most dense within layers I and II and layer VI. As individual PhAL injection sites within the perirhinal cortex were restricted to one or two adjacent laminae, we were able to determine that layer V was the main source of the perirhinofrontal projection. This was confirmed by frontal cortex injections of the retrograde tracer Fluorogold (FG). Other cortical areas with densely labelled fibers following perirhinal PhAL injections included the agranular insular, infralimbic, orbital, parietal, and entorhinal cortices. Moderate to mild fiber labelling was also noted in the posterior piriform, temporal and occipital cortices, and the claustrum. Subcortical labelling was seen in the nucleus accumbens; fundus striati; basal and lateral amygdala nuclei; the "acoustic thalamus"; and the central grey. Several of these cortical and subcortical projections were bilateral. The different laminar origin of these perirhinal efferents is discussed. These results confirmed our prediction of extensive direct projections from the anterior perirhinal cortex to the frontal cortex in the rat. The significance of this projection is discussed with special reference to the anatomical basis of convulsive limbic seizures.
由于惊厥性癫痫发作从前梨状前皮质的点燃部位迅速发展，我们使用顺行示踪剂菜豆白细胞凝集素（PhAL）研究了梨状传出纤维。将PhAL注入前梨状皮质后，在额叶皮质内标记出一个突出的纤维网络，该网络在I层、II层和VI层最为密集。由于梨状皮质内的单个PhAL注射部位局限于一两个相邻的层，我们能够确定V层是梨状-额叶投射的主要来源。这通过向额叶皮质注射逆行示踪剂荧光金（FG）得到了证实。在梨状PhAL注射后纤维标记密集的其他皮质区域包括无颗粒岛叶、内嗅下皮质、眶额皮质、顶叶皮质和内嗅皮质。在梨状后皮质、颞叶和枕叶皮质以及屏状核中也观察到中度至轻度的纤维标记。在伏隔核、纹状体底、杏仁核基底和外侧核、“听觉丘脑”以及中央灰质中可见皮质下标记。这些皮质和皮质下投射中有几个是双侧的。讨论了这些梨状传出纤维的不同层起源。这些结果证实了我们关于大鼠前梨状皮质向额叶皮质有广泛直接投射的预测。特别参考惊厥性边缘叶癫痫的解剖学基础讨论了这种投射的意义。
