ABSTRACT
The somatotopical pattern of the spinal projection to the lateral reticular nucleus (LRN) was examined in 16 rabbits. The anterograde transport of HRP method were used.1. Cervical, thoracic and lumbar segments all gave rise to small numbers of fibers projecting to bilateral lateral reticular subtrigeminal subnucleus (Lrs).2. Cervical, thoracic and lumbar projections to the LRN were bilateral but the cervical ascending fibers terminated predominately on the ipsilateral side. The lumbar ascending fibers projected chiefly to the contralateral side. The thoracic cord gave fibers to bilateral LRN. No significant difference could be seen between the two sides. There were certain overlapping among the distribution areas of the terminal branches from different parts of the cord.3. The spinal projections of the rabbit were predominately terminated in the caudal half of the LRN. It showed a somatotopical pattern. The cervical cord projected to the lateral 3/5 of the lateral reticular magnocellular subnucleus (Lrm) and its neighbouring part of the lateral reticular parvocellular subnucleus (Lrp). The thoracic cord projected to the medial 3/5 of the Lrm and its neighbouring part of Lrp. The lumbar cord gave afferents to the Lrp and its neighbouring part of Lrm.
ABSTRACT
HRP was injected into the cervical (3 cases) or lumbar (2 cases) spinal cord unilaterally in 5 adult cats. Labeled cells were discovered in the hypoth alamus and nearby areas. There was no obvious difference in labeling between cervical and lumbar injection cases. Labeled cells were found bilaterally with ipsilateral preponderance.he paraventricular nucleus was most heavily labeled; the posterior and lateral hypothalamic areas were less. A few labeled cells were found in the dorsal hypothalamic area and the supramamillary nucleus. Forel's area was also weakly labeled and occasional cells were found in the subthalamic nucleus and zona incerta.We were unable to find labeled cells in the dorsomedial nucleus. Labeling of the supramamillary nucleus, which was found in this sutdy, has not been mentioned in the literature available to us.
ABSTRACT
The somatotopical projection from the lateral vestibular nucleus to differentlevels of the spinal cord in the cat was studied with the horseradish peroxidasemethod.It was found that in the lateral vestibular nucleus the cells projecting tothe cervical and lumbar segments of the cord were distributed over the entire ros-trocaudal extent,each with an area of concentration.The caudal and middle thirdsof the nucleus,especially its dorsolateral part,projected to the lumbar cord.Thecells projecting to the cervical cord were concentrated at the rostral-middle thirds ofthe nucleus and those to the thoracic cord were concentrated at the dorsal part ofthe caudal-middle thirds.The area projecting to the thoracic levels seemed tocoincide with that projecting to the lumbar levels.The cells projecting to thelumbar cord were largest in number,those to the cervical cord less and those to thethoracic cord least.
ABSTRACT
The cervical, thoracic, or lumbar spinal gray was injected with HRP or WGAHRP unilaterally in 18 adult rabbits and the anterograde labeling was traced in the pontine nucleus and the caudal pontine ventrolateral tegmentum.In the pontine nucleus labeled terminal arborizations were found in its caudal 1/3, distributing in the paramedian nucleus, the dorsal part of peduncular nucleus and the dorsolateral nucleus. In the ventrolateral tegmentum four small cell groups were found labeled which were temporarily denominated as VLPT_(1～4) groups. In all locations labelings were found bilaterally and no apparent somatotopical localization could be identified.The cytoarchitecture of VLPT_(1～4) was studied on Nissl sections and their relationship with Meessen and Olszewski's (M-O's) "k" and "m" groups and with pontobulbar body was discussed. VLPT_2 (corresponding to the ventral part of M-O's "k") and VLPT_3 (corresponding to a part of M-O's "m") join each other to form one group which then merges into the dorsolateral nucleus of the pontine gray. They apparently form a part of the pontobulbar body.
ABSTRACT
HRP was injected into C_6, C_7, L_5, L_6 or T_(5～7) spinal gray. The retrogradely labeled cells and anterogradly labeled terminal arborizations were traced in L_5 and T_5 in cervical injection cases, C_5 and T_5 in lumbar cases, and C_5, L_5 in thoracic cases.Large amount of labeled cell were consistently found in laminae Ⅶ (including the lateral horn of the thoracic cord) and Ⅷ, next numerous in lamina Ⅴ and Ⅹ region. Lamina Ⅰ was found labeled in the cervical and lumbar cord, but virtually not found in the thoracic cord. Labeled cells were few and inconsistent in laminae Ⅳ and Ⅵ. A few labeled lamina Ⅸ cells could be found in the thoracic cord, only occasionally in the lumbar cord, but could not be found in the cervical cord. Laminae Ⅱ and Ⅲ were free from labeled cells in all cases. The labeled terminal arborizations were more widespread and could be found in practically every lamina, being densest in region Ⅹ, laminae Ⅶ (including the lateral horn of the thoracic cord) and Ⅷ. In lumbar injection cases a prominent plexus of labeled terminal arborization could be seen in the ventrolateral part of the C_5 ventral horn. Corresponding plexus was not found in the lumbar cord in cervical injection cases.Some labeled terminal arborizations were found in close approximation to or overlapping with labeled cells or unlabeled motor neurons.These results imply that: (1) The occurance of labeled cells and labeled terminal arborizations in the lateral part of lamina Ⅶ (lateral horn) suggests that intersegmental connection is related to visceral activities as well as somatic ones. (2) Labeled cells were consistently found in region Ⅹ which was also the area of dense labeling of terminal arborization, suggesting that this region plays a remarkable role in intersegmental connection. (3) Long ascending bundle connects the lumbar enlargement with the ventrolateral part of the motor neurons directly. (4) The close approximation of labeled terminal arborization and labeled cells signifies direct intersegmental feedback circuit.
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 projections:1) 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.
ABSTRACT
HRP was injected into the right side of the cervical or lumbar enlargement ormidthoracic segment of adult cats.Retrogradely labeled cells in the red nucleuswere examined and their somatotopic localization was determined.1.The Rubro-spinal projection was mainly crossed with obvious somatotopiclocalization.The dorsal medial part of the red nucleus projected to the cervicalenlargement.The ventral lateral part of the red nucleus projected to the lumbarenlargement.The neurons between these two parts projected to the thoracic cord.2.In cervical and lumbar injected cases a few labeled cells were found also inthe ipsilateral red nucleus,suggesting a minor ipsilateral rubrospinal projection exist-ed.No ipsilateral labeling was found in the thoracic injection cases.3.The rubrospinal tract could at least project to as low as L 6 segment of thespinal cord.
ABSTRACT
HRP or WGA-HRP was injected into the rabbit cervical, thoracic, or lumbar spinal gray unilaterally and the retrograde labeled ceils and anterograde labeled terminal branches in the nucleus of the solitary tract were studied. The labeled cells were found in the caudal part of the nucleus. The amount of the labeled cells in the cervical and thoracic injection cases out numbered that of the lumbar cases. In all the cases labeled ceils were most concentrated near the obex level, mainly located ventromedial to the tract. Some could be found ventral, ven- trolateral, lateral and medial to and in the vicinity of the tract. In the medial part of the nucleus labeled cells were limited in its ventral part dorsal to the dorsal motor nucleus of the vagus nerve. No labeling could be ascertained in the subnucleus parvocellularis. In the thoracic injection cases a group of labeled cells were discovered dorsolateral to the tract where only a few labeled ceils could be found in the cervical and lumbar cases. Labeled terminal branches largely accompanied the labeledcells. Thus the chance of establishing direct synaptic contact between spino-solitary fibers and the spinal projection cells of the nucleus of the solitary tract is great. At the level of obex a narrow band of terminal labeling along the dorsolateral border of the nucleus was identified. Except occasionally no labeled cells were found in this zone, an area probably related to cardiac function.
ABSTRACT
Neurons descending from the griseum centrale mesencephali, nucleus Darkschewitsch and nucleus interstitialis of Cajal to the nucleus raphe magnus and adjacent reticular formation (nucleus reticularis gigantocellularis and nucleus reticularis pontis caudalis) were identified in 9 adult cats with the retrograde HRP method. In the griseum centrale mesencephali, the labeled neurons were found bilaterally but slightly more ipsilaterally. In the nucleus Darkschewitscb and nucleus interstitialis of Cajal, the labeled neurons were consistently found in its rostral part ipsilateral to the injected side at the level of the posterior commissure. In addition, in 5 of the 9 cases, a few labeled neurons were observed in the nucleus raphe dorsalis.
ABSTRACT
It has been found by Ju('81)that HRP could be anterogradely transported forlong distances.Based on this fact the rate of anterograde transport was investigatedin the present study,and,at the same time,the rate of retrograde transport and thetime of disappearance of HRP from the labeled sites were observed.Twenty tworabbits,weighing 2～2.2 kg,were used.The HRP was injected into the lower lumbarspinal cord unilaterally.The animals were sacrificed after 12 hours to 7 days andwere processed with benzidine and o-dianisidine.The anterogade labeling in the dorsalaccessory olivary nucleus and the retrograde labeling in the red nucleus and thenucleus raphe pallidus were chosen for study.It was quite unexpected to find that the anterograde and retrograde labelingsparalled each other in time as well as in intensity.They appeared at the same timeand waxed and waned practically in full accord.Labeling of the brainstem firstappeared at 18 hour's survival,reached its peak at the 2nd day,and then graduallyfaded away till at the 7th day when only traces of labeling remained.In the casewhich showed the earliest labeling the distance between the injection site and theobex,which was at about the same level as the most densely labeled parts of thedorsal accessory olivary nucleus and nucleus raphe pallidus,was measured to be 265mm and the rate of transport,the same for anterograde and retrograde transports,was calculated to be more than 350mm per day.Counting from the time of theearliest labeling,HRP was found to remain at the labeled site for as long as 5～6 days.The period of net accumulation of HRP at the labeled sites was about 1 day.Thus,the best survival period would be roughly the time required for HRP to travel thefiber tract plus 1 day.Neurons of the red nucleus and the nucleus raphe pallidus differ greatly intheir morphology,physiology as well as biochemistry.The results in them however,were similar.This,in connection with observations on other nuclei,both anterogr-adely and retrogradely labeled,suggests that the rate of transport and the duration ofpreservation of HRP in the central nervous system are basically the same in differentneuronal systems.