Kuramoto Eriko, Ohno Sachi, Furuta Takahiro, Unzai Tomo, Tanaka Yasuhiro R, Hioki Hiroyuki, Kaneko Takeshi
Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan Department of Dental Anesthesiology, Graduate School of Medicine and Dentistry, Kagoshima University, Kagoshima 890-8544, Japan.
Cereb Cortex. 2015 Jan;25(1):221-35. doi: 10.1093/cercor/bht216. Epub 2013 Aug 22.
Not only inhibitory afferent-dominant zone (IZ) of the ventral anterior-ventral lateral thalamic complex (VA-VL) but also the ventral medial nucleus (VM) is known to receive strong inputs from the basal ganglia and send axons to motor areas. We previously reported differences in axonal arborization between IZ neurons and the other VA-VL neurons in rats by single-neuron tracing with viral vectors. In the present study, the axonal arborization of single VM neurons was visualized by the same method, and compared with that of IZ neurons. VM neurons formed fewer axon collaterals in the striatum, but sent axon fibers more widely and more preferentially (79% of fibers) to layer 1 of cortical areas than IZ neurons. Furthermore, the VM seemed to contain at least 2 types of neurons; a major population of VM neurons sent axon fibers principally to motor-associated areas as VA-VL neurons did, and the other population projected mainly to orbital or cingulate areas. Although both VM and IZ neurons receive strong basal ganglia inputs, these results suggest that VM neurons, at a single neuron level, innervate the apical dendrites of cortical pyramidal neurons more intensely and more widely than IZ neurons.
已知腹前-腹外侧丘脑复合体（VA-VL）的抑制性传入优势区（IZ）以及腹内侧核（VM）都接收来自基底神经节的强大输入，并向运动区域发送轴突。我们之前通过病毒载体进行单神经元追踪，报道了大鼠IZ神经元与其他VA-VL神经元在轴突分支上的差异。在本研究中，采用相同方法观察了单个VM神经元的轴突分支，并与IZ神经元进行了比较。VM神经元在纹状体中形成的轴突侧支较少，但与IZ神经元相比，其轴突纤维更广泛且更优先地（79%的纤维）投射到皮质区域的第1层。此外，VM似乎至少包含2种类型的神经元；大部分VM神经元像VA-VL神经元一样，主要将轴突纤维投射到与运动相关的区域，而另一部分则主要投射到眶区或扣带回区域。尽管VM和IZ神经元都接收来自基底神经节的强大输入，但这些结果表明，在单神经元水平上，VM神经元比IZ神经元更强烈、更广泛地支配皮质锥体细胞的顶端树突。
