THE PROJECTION OF THE LOWER BRAIN STEM TO THE CERVICAL AND LUMBAR ENLARGEMENTS OF THE SPINAL CORD IN CATS——HRP METHOD / 解剖学报

ABSTRACT

The projection from the lower brain stem to the spinal cord was studied with HRP method by injecting HRP into the cervical and lumbar enlargements of the spinal cord of 10 cats.The follwing nuclei were found to have spinal projections1) The reticular formation Numerous retrogradely labeled cells were seen in the nuclei of gigantocellularis and medullae oblongatae centralis subnucleus ventralis, fewer in the nuclei pontis centralis caudalis and oralis. A few labeled neurons were also found in the nuclei of medullae oblongatae centralis subnucleus dorsalis, parvocellularis, paragigantocellularis laterlaris, paramedium reticularis subnucleus ventralis and cuneiformis. Most of them projected to the spinal gray matter ventral to the dorsal horn except the nuclei of medullae oblongatae centralis subnucleus dorsalis and parvocellularis which projected mainly to the dorsal horn.2) The raphe nuclei Nuclei of raphe pallidus, magnus and obscurus projected to both the cervical and lumbar enlargements, while nucleus raphe dorsalis only to the gray matter ventral to the dorsal horn of the cervical enlargement.3) The gracile and medial cuneatus nuclei projected somatotopically to ipsilateral spinal cord.4) The cranial nuclei The Edinger-Westphal nucleus, nuclei of nervi oculomotor principalis, tractus spinalis nervi trigemini and tractus solitarii and the nuclei vestibularis lateralis, medialis, superior and spinalis were found to project to spinal cord. There was somatotopic arrangement in the nucleus vestibularis lateralis.5) The nuclei of locus coeruleus, subcoeruleus, parabrachialis lateralis and medialis, neucleus retroambigualis and the Kolliker-Fuse nucleus projected bilaterally to the spinal cord.6) The red nucleus Large amount of labeled cells were seen in the controlateral red nucleus. The ventrolateral part of the red nucleus projected to the cervical enlargement while the dorsornedial part to the lumbar enlargement.7) The superior colliculus and the griseum centrale mesencephali projected to the gray matter ventral to the dorsal horn of the cervical enlargement.