Bense Sandra, Janusch Barbara, Vucurevic Goran, Bauermann Thomas, Schlindwein Peter, Brandt Thomas, Stoeter Peter, Dieterich Marianne
Department of Neurology, Johannes Gutenberg-University of Mainz, Langenbeckstrasse 1, 55101, Mainz, Germany.
Exp Brain Res. 2006 Sep;174(2):312-23. doi: 10.1007/s00221-006-0464-0. Epub 2006 Apr 25.
Animal studies have shown that not only cortical, but also brainstem and cerebellar areas are involved in the initiation and generation of optokinetic nystagmus (OKN), e.g., cortico-(pretecto)pontine-olivo-cerebellar pathways. The aim of this fMRI study was to identify and differentiate brainstem and cerebellar areas involved in horizontal and vertical OKN (h/vOKN) in humans. In a group of nine healthy volunteers, hOKN and vOKN were statistically compared with a stationary control condition. There were common activated regions for hOKN and vOKN directions located in the transition zone between the posterior thalamus and the mesencephalon bilaterally covering the pretectal nucleus complex, which is known to be a major structure within the afferent branch of the optokinetic system. Furthermore, during hOKN, activation occurred bilaterally in the mediodorsal and dorsolateral ponto-medullary brainstem, which could be best attributed to the reticular formation, especially the paramedian pontine reticular formation (PPRF). For vOKN, additional activated areas in the dorsal mesencephalic brainstem could be best localized to the ocular motor nuclei and the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). For both OKN directions, the cerebellar activation was localized in the oculomotor vermis (declive VI, folium and tuber VIIA/B, in part pyramis VIIIA), and the flocculus bilaterally as well as widespread in the cerebellar hemispheres. In conclusion, fMRI allowed first attributions of neuronal substrates in the cerebellum and brainstem to hOKN and vOKN in humans. Consistent with the animal data, the dorsal ponto-medullary routes were involved bilaterally for hOKN, whereas the rostral mesencephalic routes were involved for vOKN.
动物研究表明，不仅皮质区域，而且脑干和小脑区域都参与视动性眼球震颤（OKN）的起始和产生，例如皮质-（顶盖前区）脑桥-橄榄-小脑通路。这项功能磁共振成像（fMRI）研究的目的是识别和区分人类水平和垂直视动性眼球震颤（h/vOKN）所涉及的脑干和小脑区域。在一组9名健康志愿者中，对hOKN和vOKN与静止对照状态进行了统计学比较。hOKN和vOKN方向有共同的激活区域，位于双侧丘脑后部和中脑之间的过渡区，覆盖顶盖前核复合体，该复合体是视动系统传入分支中的一个主要结构。此外，在hOKN期间，双侧的内侧背侧和背外侧脑桥-延髓脑干出现激活，这最可能归因于网状结构，尤其是脑桥旁正中网状结构（PPRF）。对于vOKN，中脑背侧脑干的额外激活区域最可能定位于动眼神经核和内侧纵束的嘴侧间质核（riMLF）。对于两个OKN方向，小脑激活定位于动眼小脑蚓部（小脑小叶VI、小叶和VIIA/B结节，部分为VIIIA锥体），双侧绒球以及小脑半球广泛区域。总之，fMRI首次确定了人类小脑和脑干中与hOKN和vOKN相关的神经元基质。与动物数据一致，hOKN双侧涉及背侧脑桥-延髓通路，而vOKN涉及中脑嘴侧通路。
