Terenzi M G, Zagon A, Roberts M H
Department of Anatomy, School of Medical Sciences, University of Bristol, UK.
Brain Res. 1995 Dec 1;701(1-2):183-91. doi: 10.1016/0006-8993(95)01001-8.
The anterior pretectal nucleus has been described as part of the visual pretectal complex. However, several electrophysiological and behavioural studies showed that this area is involved in somatosensory modulation, more specifically, antinociception. The efferents of the anterior pretectal nucleus have not been identified taking into account the different function of this nucleus in relation to the rest of the pretectal complex. In the study herein described, a sensitive anterograde tracer Phaseolus vulgaris leucoagglutinin was used to trace the mesencephalic and diencephalic efferents of the anterior pretectal nucleus in the rat. The majority of the connections were ipsilateral. Fibres with varicosities were observed in discrete areas of the thalamus (central lateral, posterior complex), hypothalamus (lateral, posterior and ventromedial), zona incerta, parvocellular red nucleus, intermediate and deep layers of the superior colliculus, central grey, deep mesencephalon, pontine parabrachial region, and pontine nuclei. Fibres en passant were detected in the medial lemniscus, from the level of the injection site to rostral medullary levels. Some labelled axons were seen coursing to the contralateral side through the posterior commissure and the decussation of the superior cerebellar peduncle. These results show that the anterior pretectal nucleus projects principally to areas involved in somatosensory and motor control in a manner that permits sensory modulation at higher and lower levels of the brain. These connections may explain the antinociceptive and antiaversive effects of stimulating the anterior pretectal nucleus in freely moving animals.
前顶盖前核被描述为视觉顶盖前复合体的一部分。然而，多项电生理和行为学研究表明，该区域参与躯体感觉调制，更具体地说，参与抗伤害感受。考虑到该核相对于顶盖前复合体其他部分的不同功能，其传出纤维尚未得到明确鉴定。在本文所述的研究中，使用了一种敏感的顺行示踪剂菜豆白细胞凝集素，来追踪大鼠前顶盖前核的中脑和间脑传出纤维。大多数连接是同侧的。在丘脑（中央外侧核、后复合体）、下丘脑（外侧、后部和腹内侧核）、未定带、小细胞红核、上丘中间层和深层、中央灰质、中脑深部、脑桥臂旁区域和脑桥核的离散区域观察到有曲张体的纤维。在从注射部位到延髓嘴侧水平的内侧丘系中检测到了通过纤维。一些标记的轴突通过后连合和上小脑脚交叉向对侧延伸。这些结果表明，前顶盖前核主要投射到参与躯体感觉和运动控制的区域，其方式允许在大脑的高级和低级水平进行感觉调制。这些连接可能解释了在自由活动动物中刺激前顶盖前核的抗伤害感受和抗厌恶作用。
