Holstege G, Tan J, van Ham J J, Graveland G A
Brain Res. 1986 May 28;374(2):321-34. doi: 10.1016/0006-8993(86)90426-9.
In the cat retractor bulbi (RB) muscle reflexively retracts the eye ball into the orbit. This reflex action is called the nictitating membrane response which, together with the reflex contraction of the orbicularis oculi muscle, constitutes the blink reflex. The retractor bulbi (RB) motoneuronal nucleus is a small cell group located in the lateral tegmentum of the caudal pons, just dorsal to the superior olivary complex. The nucleus is identical to the accessory abducens nucleus and sends its fibers through the abducens nerve. Autoradiographical tracing results indicate that the RB nucleus receives some fibers from the principal and rostral spinal trigeminal nuclei and from the dorsal red nucleus and dorsally adjoining tegmentum. The same areas project to the intermediate facial subnucleus, containing motoneurons innervating the orbicularis oculi muscle. It is suggested that the trigeminal projections take part in the anatomical framework for the R1 component of the blink reflex. Two other brainstem areas i.e.: a portion of the caudal pontine ventrolateral tegmental field and the medullary medial tegmentum at the level of the hypoglossal nucleus were also found to project to the RB motoneuronal cell group and to the intermediate facial subnucleus. These projections were much stronger than those derived from the trigeminal nuclei and red nucleus. Moreover, the medullary premotor area projects not only to the blink motoneuronal cell groups but also to the pontine premotor area. It is suggested that both areas are involved in the R2 blink reflex component. The medullary blink premotor area receives afferents especially from oculomotor control structures in the reticular formation of the brainstem while the pontine blink premotor area receives afferents from the olivary pretectal nucleus and/or the nucleus of the optic tract and from the dorsal red nucleus and its dorsally adjoining area. Because the oculomotor control structures in the reticular formation (by way of the superior colliculus) and the red nucleus receive afferents from trigeminal nuclei, they may play an important role in tactually induced reflex blinking, while the pretectum could take part in the neuronal framework of the visually induced blink reflex.
在猫中，眼球退缩肌（RB）可反射性地将眼球缩入眼眶。这种反射动作称为瞬膜反应，它与眼轮匝肌的反射性收缩共同构成眨眼反射。眼球退缩肌（RB）运动神经元核是位于脑桥尾端外侧被盖的一个小细胞群，恰好在上橄榄复合体的背侧。该核与展神经副核相同，并通过展神经发出其纤维。放射自显影追踪结果表明，RB核接收来自三叉神经脊束核主核和吻侧核以及背侧红核和背侧相邻被盖的一些纤维。相同区域投射到面神经中间亚核，该亚核包含支配眼轮匝肌的运动神经元。有人认为三叉神经投射参与了眨眼反射R1成分的解剖学框架。另外还发现脑干的其他两个区域，即脑桥尾端腹外侧被盖区的一部分和舌下神经核水平的延髓内侧被盖，也投射到RB运动神经元细胞群和面神经中间亚核。这些投射比来自三叉神经核和红核的投射要强得多。此外，延髓前运动区不仅投射到眨眼运动神经元细胞群，还投射到脑桥前运动区。有人认为这两个区域都参与了眨眼反射的R2成分。延髓眨眼前运动区尤其从脑干网状结构中的动眼神经控制结构接收传入纤维，而脑桥眨眼前运动区从橄榄前顶盖核和/或视束核以及背侧红核及其背侧相邻区域接收传入纤维。因为网状结构中的动眼神经控制结构（通过上丘）和红核从三叉神经核接收传入纤维，它们可能在触觉诱发的反射性眨眼中起重要作用，而顶盖前区可能参与视觉诱发的眨眼反射的神经元框架。
