Asanuma C
Laboratory of Neurophysiology, National Institute of Mental Health, Poolesville, MD 20837.
Proc Natl Acad Sci U S A. 1989 Jun;86(12):4746-50. doi: 10.1073/pnas.86.12.4746.
A dense axonal plexus, arising in a portion of the magnocellular basal nucleus, was identified in the thalamic reticular nucleus in adult rats. The details of these axonal arbors as well as their relation to the neurons of the reticular nucleus were investigated by using Phaseolus vulgaris leucoagglutinin injections into the basal nucleus and intracellular injections of Lucifer yellow into reticular nucleus neurons. Axons arising in the caudal basal nucleus at the medial margin of the globus pallidus do not enter the dorsal thalamus but are confined to the reticular nucleus, where they arborize widely and densely. Neurons in the reticular nucleus are large, with sparsely spined and beaded dendrites, which radiate within the plane of the nucleus. Bouton-like swellings along basal nucleus axons are often found apposed to the somata of reticular nucleus neurons, although many are also apposed to dendrites. These morphological observations suggest a second potentially significant route, in addition to its well-known direct cortical projection, through which the magnocellular basal nucleus could influence cortical function: it may, by strategically modulating the excitability of reticular nucleus neurons, alter the general state of the thalamus and hence affect the initial transmission of information to the cortex.
在成年大鼠的丘脑网状核中，发现了一个密集的轴突丛，它起源于大细胞基底核的一部分。通过将菜豆白细胞凝集素注入基底核以及将路西法黄细胞内注入网状核神经元，研究了这些轴突分支的细节及其与网状核神经元的关系。起源于苍白球内侧边缘尾侧基底核的轴突不进入背侧丘脑，而是局限于网状核，在那里它们广泛而密集地分支。网状核中的神经元很大，有稀疏的棘突和串珠状树突，这些树突在核平面内呈放射状分布。尽管许多基底核轴突上的纽扣状肿胀也与树突相邻，但通常发现它们与网状核神经元的胞体相邻。这些形态学观察结果表明，除了其众所周知的直接皮质投射外，大细胞基底核可能还有另一条潜在的重要途径来影响皮质功能：它可能通过策略性地调节网状核神经元的兴奋性，改变丘脑的总体状态，从而影响信息向皮质的初始传递。
