Berendse H W, Groenewegen H J
Department of Anatomy and Embryology, Vrije Universiteit, Amsterdam, The Netherlands.
Neuroscience. 1991;42(1):73-102. doi: 10.1016/0306-4522(91)90151-d.
The projections from the midline and intralaminar thalamic nuclei to the cerebral cortex were studied in the rat by means of anterograde tracing with Phaseolus vulgaris-leucoagglutinin. The midline and intralaminar nuclear complex taken as a whole projects to widespread, predominantly frontal, cortical areas. Each of the constituent thalamic nuclei has a restricted cortical projection field that overlaps only slightly with the projection fields of adjacent midline and intralaminar nuclei. The projections of the intralaminar nuclei cover a larger cortical area than those of the midline nuclei. The laminar distributions of fibres from individual midline and intralaminar thalamic nuclei are different and include both deep and superficial cortical layers. The parataenial, paraventricular and intermediodorsal midline nuclei each project to circumscribed parts of the prefrontal cortex and the hippocampal and parahippocampal regions. In the prefrontal cortex, the projections are restricted to the medial orbital, infralimbic, ventral prelimbic and agranular insular fields, and the rostral part of the ventral anterior cingular cortex. In contrast to the other midline nuclei, the rhomboid nucleus projects to widespread cortical areas. The rostral intralaminar nuclei innervate dorsal parts of the prefrontal cortex, i.e. the dorsal parts of the prelimbic, anterior cingular and dorsal agranular insular cortical fields, the lateral and ventrolateral orbital areas, and the caudal part of the ventral anterior cingular cortex. Additional projections are aimed at the agranular fields of the motor cortex and the caudal part of the parietal cortex. The lateral part of the parafascicular nucleus sends fibres predominantly to the lateral agranular field of the motor cortex and the rostral part of the parietal cortex. The medial part of the parafascicular nucleus projects rather sparsely to the dorsal part of the prelimbic cortex, the anterior cingular cortex and the medial agranular field of the motor cortex. Individual midline and intralaminar thalamic nuclei are thus in a position to directly influence circumscribed areas of the cerebral cortex. In combination with previously reported data on the organization of the midline and intralaminar thalamostriatal projections and the prefrontal corticostriatal projections the present results suggest a high degree of differentiation in the convergence of thalamic and cortical afferent fibres in the striatum. Each of the recently described parallel basal ganglia-thalamocortical circuits can thus be expanded to include projections at both the cortical and striatal levels from a specific part of the midline and intralaminar nuclear complex. The distinctive laminar distributions of the fibres originating from the different nuclei emphasize the specificity of the midline and intralaminar thalamocortical projections.
采用菜豆白细胞凝集素进行顺行示踪，研究了大鼠丘脑中线核和板内核向大脑皮质的投射。作为一个整体，中线核和板内核复合体投射到广泛的、主要是额叶的皮质区域。每个组成性丘脑核都有一个受限的皮质投射区，与相邻的中线核和板内核的投射区仅有轻微重叠。板内核的投射覆盖的皮质区域比中线核的投射覆盖的区域更大。来自单个中线核和板内核的纤维在皮质各层的分布不同，包括皮质深层和浅层。旁室核、室旁核和中间背侧中线核各自投射到前额叶皮质、海马和海马旁区域的特定部分。在前额叶皮质，投射局限于内侧眶回、嗅周皮质、腹侧前边缘皮质和无颗粒岛叶皮质区，以及腹侧前扣带回皮质的嘴侧部分。与其他中线核不同，菱形核投射到广泛的皮质区域。嘴侧板内核支配前额叶皮质的背侧部分，即前边缘皮质、前扣带回皮质和背侧无颗粒岛叶皮质区的背侧部分、外侧和腹外侧眶回区域，以及腹侧前扣带回皮质的尾侧部分。额外的投射指向运动皮质的无颗粒区和顶叶皮质的尾侧部分。束旁核外侧部分主要向运动皮质的外侧无颗粒区和顶叶皮质的嘴侧部分发送纤维。束旁核内侧部分稀疏地投射到前边缘皮质的背侧部分、前扣带回皮质和运动皮质的内侧无颗粒区。因此，单个中线核和板内核能够直接影响大脑皮质的特定区域。结合先前报道的关于中线核和板内核丘脑纹状体投射以及前额叶皮质纹状体投射的组织学数据，目前的结果表明丘脑和皮质传入纤维在纹状体中的汇聚具有高度分化。因此，最近描述的每个平行的基底神经节 - 丘脑皮质回路都可以扩展，以包括来自中线核和板内核复合体特定部分在皮质和纹状体水平的投射。源自不同核的纤维独特的分层分布强调了中线核和板内核丘脑皮质投射的特异性。
