Edwards S B, Henkel C K
J Comp Neurol. 1978 May 15;179(2):451-67. doi: 10.1002/cne.901790212.
Direct and indirect projections from the cat superior colliculus to the extraocular motor nuclei were studied using the orthograde autoradiographic tracing method, the retrograde horseradish peroxidase technique, and Golgi methods. The results show that the superior colliculus projects to the central gray matter directly overlying the oculomotor complex. This projection arises almost entirely from the rostral third of the colliculus, and it terminates most heavily over the rostral half of the oculomotor complex. Dendrites of oculomotor cells extend into this tectal termination zone, making direct tecto-oculomotor contacts possible. Central gray cells within this termination zone project bilaterally to the abducens nuclei. It is proposed that the superior colliculus projection to the supraoculomotor central gray matter and the projection from the central gray matter to the abducens nuclei play a role in convergent eye movements. The superior colliculus projects lightly to a cell group directly ventrolateral to the trochlear nucleus. The superior colliculus sends a small direct projection to the contralateral abducens nucleus and a substantial projection to wide regions of the reticular formation that have been shown previously to project, in turn, to the abducens nucleus. Colliculus cells projecting to the abducens nucleus and adjacent reticular formation are located only in the caudal three-fourths of the colliculus, where they become increasingly concentrated at successively more caudal levels. It is proposed that the graded density of the cells of origin of this projection is the basic structural mechanism by which the colliculus generates horizontal foveating saccades of different amplitudes. Laminar analysis of the origin of all the superior colliculus projections to the extraocular motor regions described here revealed that they arise mostly from the stratum griseum intermedium.
运用顺行性放射自显影追踪法、逆行性辣根过氧化物酶技术以及高尔基方法，对猫上丘到眼外肌运动核的直接和间接投射进行了研究。结果显示，上丘直接投射到动眼神经复合体上方的中央灰质。这种投射几乎完全起源于上丘的前三分之一，并且在动眼神经复合体的前半部分终止最为密集。动眼神经细胞的树突延伸至这个顶盖终止区，使得顶盖与动眼神经之间能够直接接触。该终止区内的中央灰质细胞双侧投射至展神经核。有人提出，上丘投射到动眼神经上方的中央灰质以及中央灰质投射到展神经核，在眼球的集合运动中发挥作用。上丘轻微投射至滑车神经核正腹外侧的一个细胞群。上丘向对侧展神经核发出一小束直接投射，并向网状结构的广泛区域发出大量投射，而先前已表明这些网状结构区域会依次投射至展神经核。投射到展神经核及相邻网状结构的上丘细胞仅位于上丘的后四分之三部分，在这些区域，它们在越靠后的层面上越来越集中。有人提出，这种投射的起源细胞密度梯度是上丘产生不同幅度水平注视性扫视的基本结构机制。对这里描述的上丘向眼外肌运动区域的所有投射起源进行分层分析表明，它们大多起源于中间灰质层。
