上丘为一古老的分层结构。一些解剖学和生理学资料证明

上丘浅层和深层有着不同的纤维投射

其浅层主要接受视网膜和纹状皮质的输入

而深层除与视觉有关外

还是各种感觉的会聚地带。近来Edwar-ds通过形态学研究证明上丘广泛接受视结构、听结构、体感觉结构、儿茶酚胺神经核团以及特殊网状区的输入

从而认为上丘深层具有脑干中心网状结构的性质。已知脑干网状结构与针刺镇痛作用有关

而上丘也有人认为涉及到痛觉机理

因而了解上丘与脑内有关疼痛和镇痛的某些结构之间的联系是很有必要的

这对针刺镇痛The connections between superior colliculus and some nociceptive and anti-nociceptive nuclei in the cat brain were studied by a combined antro- grade and retrograde tracing technique. Following HRP injections into the superior colliculus

both HRP-posi- tive cells and labeled terminals were found in the zona incerta

mainly ipsilaterally. when HRP was injected into rostral superior colliculus

a number of labeled terminals might be observed in the zona incerta

but did not show and labeled cells there. After HRP injections into rostral-middle region of superior colliculus

retrograde labeled cells were presented densely in the ipsilateral zona incerta

but labeled terminals were considerably sparse. Following HRP injections into the caudal superior colliculus

there were little labeled terminals

but labeled cells presented mildly. In spite of the site of superior colliculus where the HRP was injected

labeled cells were generally found in ventral division of thalamic reticular nucleus but clearly in decreased number. In the cases in which only the rostral superior colliculus was injected

the labeled (terminals) were observed in caudal part of thalamic reticular nucleus

thalamic parafascicular nucleus and centromedian nucleus

mainly ipsilaterally. In addition

a large amount of labeled cells were found in ipsilateral reticular part of substantia nigra and contralateral nucleus tractus spinalis trigemini oralis γ

but lateral part of substantia nigra

the ventral and lateral division of periaquaeductal gray substance

nucleus of locus caeruleus

subcaeruleus

raphe nuclei of midbrain

and subnucleus ventralis of contralateral nucleus trigemini sensiblis princi- palis contained a few of HRP-positive cells. It is suggesting that the connections between superior colliculus and nociceptive and anti-nociceptive structures in the cat are considerably abundant. We propose that these con- nections may be considered as the morphological bases of noxious and anti-noxious sensory input.