Wilson V J
Rockefeller University, New York, NY 10021.
Prog Brain Res. 1993;97:211-7. doi: 10.1016/s0079-6123(08)62280-3.
While both vestibulospinal and reticulospinal tracts contribute to vestibulospinal reflexes, their respective roles are not fully understood. Previous evidence suggests that reticulospinal fibers make an important contribution to the horizontal vestibulocollic reflex (VCR) of the decerebrate cat. Recent work addresses their contribution to the vertical VCR. On the basis of study of reflex and vestibulocollic neuron dynamics, it appears that processing which is necessary to produce some of the spatial properties of the vertical VCR takes place outside the vestibular nuclei. Recording from pontomedullary reticulospinal neurons receiving vestibular input and projecting to different levels of the spinal cord reveals that almost no cells receive only vertical canal input, while approximately half receive otolith input. As is the case for vestibulocollic neurons, these reticulospinal neurons also lack the properties required to produce all of the VCR's spatial properties. Two conclusions are that in response to stimuli in vertical planes pontomedullary reticulospinal fibers are best suited to contribute to otolith reflexes, and that spatial properties of the VCR depend in part on convergence of inputs within the neck itself.
虽然前庭脊髓束和网状脊髓束都参与前庭脊髓反射，但其各自的作用尚未完全明确。先前的证据表明，网状脊髓纤维对去大脑猫的水平前庭颈反射（VCR）有重要贡献。最近的研究探讨了它们对垂直VCR的贡献。基于对反射和前庭颈神经元动力学的研究，产生垂直VCR某些空间特性所必需的处理似乎发生在前庭核之外。对接受前庭输入并投射到脊髓不同水平的脑桥延髓网状脊髓神经元进行记录发现，几乎没有细胞仅接受垂直半规管输入，而约一半细胞接受耳石输入。与前庭颈神经元情况相同，这些网状脊髓神经元也缺乏产生所有VCR空间特性所需的特性。得出两个结论：一是在垂直平面受到刺激时，脑桥延髓网状脊髓纤维最适合参与耳石反射；二是VCR的空间特性部分取决于颈部自身内输入的汇聚。
