The brainstem localization of gastric preganglionic parasympathetic neurons in the Agouti (Dasyprocta leporina) / Localización del tronco encefálico de las neuronas parasimpáticas preganglionares gástricas en el agutí (Dasyprocta leporina)

This study was designed to determine qualitatively, the source of gastric vagal nerve fibres in the Agouti. A total of 18 male and female adult agoutis were used for the present investigation. Following anaesthesia, laparotomy was performed and the stomach exteriorized. Multiple intramuscular injections of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) were then made into different areas of the stomach in the experimental animals. The control animals were divided into four groups of two animals each. The first group had intraperitoneal injection of the tracer, the second had intramuscular injection of normal saline, the third group had injection of tracer into the hepatic portal vein and the last group had injection of the tracer into the gastric walls followed immediately by bilateral vagotomy. Following a survival period offive to seven days, the animals were sacrificed by transcardial perfusion, first with normal saline followed by fixative and finally with 20% buffered sucrose. Following perfusion, the brainstem was extracted from the brain, immersed in 20% buffered sucrose and kept refrigerated overnight for cryoprotection. The brainstems were subsequently sectioned serially, processed for WGA-HRP neurohistochemistry and then analysed under light and dark-field illuminations. The analysis of the sections taken from the experimental animals revealed bilateral presence of WGA-HRP labelled neurons in the dorsal motor nucleus of the vagus nerve (DMNV) and the nucleus ambiguus (nA) of the medulla oblongata. No labelled neurons were seen in any of the sections taken from the control animals. The implications of the findings are discussed.

Este estudio fue diseñado para determinar cualitativamente el origen de las fibras gástricas del nervio vago en el agutí. Un total de 18 agutíes adultos masculinos y femeninos fueron utilizados para la presente investigación. Después de la anestesia, se realizó una laparotomía y se sacó el estómago al exterior. Luego se hicieron múltiples inyecciones intramusculares de aglutinina de germen de trigo con peroxidasa de rábano (WGA-HRP) en diferentes áreas del estómago de los animales experimentales. Los animales del control fueron divididos en cuatro grupos de dos animales cada uno. Al primer grupo se le puso una inyección intraperitoneal del marcador; al segundo se le administró una inyección intramuscular de solución salina normal; al tercer grupo se le inyectó el marcador en la vena porta hepática; y al último grupo se le puso la inyección del marcador en las paredes gástricas, seguida inmediatamente por una vagotomía bilateral. Tras un periodo de supervivencia de cinco a siete días, los animales fueron sacrificados por perfusión transcardíaca, primero con solución salina normal, seguida de fijador, y finalmente con sacarosa tamponada al 20%. Después de la perfusión, el tronco encefálico fue extraído del cerebro, inmerso en sacarosa tamponada al 20%, y mantenido en refrigeración durante la noche para su crioprotección. Los tronos encefálicos fueron luego seccionados en serie, procesados para para el análisis neuro-histoquímico mediante aglutinina de germen de trigo con peroxidasa de rábano, y analizados entonces bajo iluminaciones de campo de luz y campo oscuro. El análisis de las secciones tomadas de animales experimentales reveló la presencia bilateral de neuronas etiquetadas WGA-HRP en el núcleo motor dorsal del nervio vago (DMNV) y en el núcleo ambiguo (nA) de la médula oblonga. No se observaron neuronas etiquetadas en ninguna de las secciones tomadas de los animales de control. Se discuten las implicaciones de los hallazgos.

Morphological Changes of the Sensory Neurons in the Peripheral Neuropathy of Rat Tibial Nerve Using WGA-HRP Tracing Method / 체질인류학회지

Neuropathy is a general term referring to disorders of nerves, and produces when the nerves are damaged. It is characterized by spontaneous pain, allodynia and hyperalgesia. The purpose of present study is to observe the number of WGA-HRP (wheat germ agglutinin-horseradish peroxidase) labelded sensory neurons of DRG (dorsal root ganglia), and distributions according to cell size of sensory neuron in tibial nerve ligation model (NLM). The tibial nerve ligation was performed with 3-0 silk by the application of three tight ligatures at the mid-thigh level. In the neuropathy model of rat tibial nerve ligation, morphological changes of sensory neurons in DRG were observed using WGA-HRP. Rats of NLM showed the neuropathic behaviors. Rats were shown guarding affected limb and limping. Their toes and ankle joint of operated limb were hyperflexed. Under light microscopy, tibial nerve showed degeneration of axons in NLM. In control and NLM, labeled sensory neurons of tibial nerve distributed L4 and L5 DRG. In control group, the labeled sensory neurons were round or oval in shape. They were large and small cells, and mixed pattern. Total number of labeled sensory neurons in NLM decreased significantly from control group. The number of labeled sensory neurons in L4 and L5 DRG decreased significantly from control group. Labeled large and small cells decreased significantly from control group. Present study may serve as the basic information about the changes of DRG sensory neurons in NLM.

A Study on the Spinoreticulocerebellar Tract in Chickens

The spicoreticulocerebellar (SRC) tract is an indirect spinocerebellar tract formed by the reticular formation (RF), which is connected to the cerebellum and spinal cord. The RF receives ascending fibers to both the spinal enlargement and sends descending fibers to the cerebellum. This study demonstrated that the connectivity of the neurons in the RF is concerned to the cerebellum and spinal cord using the anterograde projection with biotinylated dextran amine (BDA) and retrograde labeling with wheat germ agglutinin-horseradish peroxidase (WGA-HRP). Until now, a preliminary study in mammals has dealt with the afferent and efferent pathways in separating groups of neurons in the RF. There are only few reports on chickens. This study examined the SRC tract in chickens. Following bilateral injections we injected BDA into chicken spinal cord (lumbosacral enlargement) and WGA-HRP into the cerebellum. Both of single- and double-labeled cells were found within the RF. The spinoreticular axons were mainly distributed from the potomedullary junction to the rostral medulla in the rostro-caudally RF levels, for example, nucleus of reticularis (n. r.) pontis oralis, locus coeruleus, n. r. pontis caudalis, n. r. pars gigantocellularis, n. r. gigantocellularis and n. r. parvocellualris. Reticulocerebellar labeling by the WGA- HRP was found in the same place as well as that of the BDA-projection. We observed that the proportion and location of double labeling cells in the chicken were almost similar in each level, comparing to the rodents. These results suggest that the reticular formation is strongly related to the spicoreticulocerebellar tract in chickens.

Ultrastructural Analysis of GABA- and Glycine-Immunoreactive Nerve Terminals on Jaw-Closing and Jaw-Opening Motoneurons in the Rat / 대한해부학회지

Previous studies have shown that inhibitory synaptic inputs are different between in spinal and trigeminal motor systems and activities of jaw closing and opening alpha motoneurons are different during a chewing cycle. This study examined the distribution of inhibitory synapses made on masseter and digastric motoneurons by using retrograde tracing of wheat germ agglutinin conjugated to horseradish peroxides (WGA-HRP) combined with postembedding immunogold labeling on serial ultrathin sections.Many boutons IR (immunoreactive) to GABA and/or glycine were found to appose on two kinds of motoneurons, which were containing pleomorphic vesicles (a mixture of round, oval and flattened vesicles) and exhibited symmetrical synaptic contacts on the somata. Packing density and synaptic covering % were higher in digastric than in masseter motoneurons. Of 703 boutons apposing on 12 masseter motoneurons, 6.08+/-3.51, 29.67+/-8.89 and 17.78+/-5.22% were IR to GABA only, glycine only, and both GABA and glycine, respectively. Of 637 boutons apposing on 11 digastric motoneurons, 6.37+/-4.64, 19.74+/-8.25 and 12.01+/-5.38% were IR to GABA only, glycine only, and both GABA and glycine, respectively. Proportions of glycine IR boutons were higher than that of GABA IR boutons in both masseter and digastric motoneurons. Packing density and proportion of boutons IR to GABA and/or glycine were higher in jaw closing than in jaw opening motoneurons (packing density, 12.03+/-1.58 vs 10.28+/-2.99; proportion of IR boutons, 53.54+/-8.94% vs 38.12+/-9.38% in jaw closing and opening motoneurons, respectively). These results provide ultrastructural evidence that GABA and glycine act as important neurotransmitters for modulation of jaw movement and that proportion of inhibitory synapses is higher in jaw closing than in jaw opening motoneurons.

Neural Pathway Innervating Epididymis of Rats by Pseudorabies virus (PRV-Ba-Gal) and WGA-HRP / 대한해부학회지

This experimental studies was to investigate the location of PNS and CNS labeled neurons following injection of 2% WGA-HRP and pseudorabies virus (PRV), beta-galactosidase inserted Bartha strain, into the epididymis of rats. After survival times 4~5 days following injection of 2% WGA-HRP and PRV-Ba-Gal, the rats were perfused, and their brain, spinal cord, sympathetic ganglia and spinal ganglia were frozen sectioned (30 mm). These sections were stained by HRP histochemical and beta-galactosidase histochemical staining methods, and observed with light microscope. The results were as follows : 1. The WGA-HRP labeled sympathetic ganglia projecting to the epididymis were observed in pelvic ganglion and L1-6 lumbar sympathetic ganglia. 2. The WGA-HRP labeled spinal ganglia projecting to the epididymis were observed in L1-6 spinal ganglia. 3. The beta-galactosidase labeled neurons projecting to the epididymis were observed in lamina VII of cervical segments. In thoracic segments, beta-galactosidase labeled neurons were observed in dorsomedial part of lamina I, II and III. Dense labeled neurons were observed in intermediolateral n. and dorsal commissural n.. In lumbar segment, labeled neurons were observed in lamina III, IV, V, dorsal commisural n. and superficial dorsal horn. 4. In the medulla oblongata, beta-galactosidase labeled neurons projecting to the epididymis were observed in the trigeminal spinal n., A1 noradrenalin cells/C1 adrenalin cells/caudoventrolateral reticular n., rostroventrolateral reticular n., area postrema, n. tractus solitarius, raphe obscurus n., raphe pallidus n., raphe magnus n., parapyra-midal n., lateral reticular n. and lateral paragigantocellular reticular n.. 5. In the pons, labeled neurons were observed in Kolliker-Fuse n., locus coeruleus, subcoeruleus n. and A5 noradrenalin cells. 6. In midbrain, labeled neurons were observed in periaqueductal gray substance, retrorubral n., substantia nigra and dorsal raphe n.. 7. In the diencephalon, labeled neurons were observed in paraventricular hypothalamic n., lateral hypothalamic nucleus., medial preoptic n. and retrochiasmatic n.. These results suggest that WGA-HRP labeled neurons of the spinal cord projecting to the rat epididymis might be the first-order neurons related to the viscero-somatic sensory and sympathetic postganglionic neurons, and beta-galactosidase labeled neurons of the brain and spinal cord may be the second and third-order neurons response to the movement of vascular smooth muscle in epididymis. These beta-galactosidase labeled neurons may be central autonomic center related to the integration and modulation of reflex control linked to the sensory and motor system monitoring the internal environment. These observations provide evidence for previously unknown projections from epididymis to spinal cord and brain which may be play an important neuroanatomical basic evidence in the regulation of epididymal function.

The Localization of Efferent and Afferent Neurons Innervating the Rat Thymus Using the Neural Tracers / 대한해부학회지

The localizations of efferent and afferent neurons were observed following injection of neural tracers, cholera toxin B subunit (CTB) and wheat germ agglutinin-horseradish peroxidase (WGA-HRP) into the rat thymus with ages. Thirty Sprague-Dawley rats were examined at 3 weeks, 5~6 and 20 months of age. After survival times of 48~96 hours following injection of neural tracers, the rats were perfused and their brain, spinal cord, sympathetic ganglia, dorsal root ganglia and vagal ganglia were frozen sectioned (40 mm). These sections were stained by CTB immunohistochemical and HRP histochemical staining methods, and observed with polarized dark and light microscope. The results were as follows: 1. WGA-HRP and CTB labeled parasympathetic neurons were bilaterally seen in the nucleus ambiguus and medullary reticular formation of medulla with all ages. 2. WGA-HRP labeled sympathetic neurons were bilaterally labeled in superior cervical ganglia, middle cervical ganglia, stellate ganglia and T4-8 sympathetic chain ganglia. The number of labeled sympathetic neurons was increased in the thymus at 20 months of age. According to the aging, sympathetic neuronal processes were more developed, and the nerve fibers were coarse and more branched. 3. WGA-HRP labeled sensory neurons were bilaterally observed within the vagal and C1-6 dorsal root ganglia. The number of labeled sensory neurons was decreased in the thymus at 20 months of age.

Localization of Sensory Neurons Innervating the Rat Intestine Using the Cholera Toxin B Subunit(CTB) and Wheat Germ Agglutinin-Horseradish Peroxidase(WGA-HRP) / 영남의대학술지

The local arrangement of sensory nerve cell bodies and nerve fibers in the brain stem, spinal ganglia and nodose ganglia were observed following injection of cholera toxin B subunit(CTB) and wheat germ agglutinin-horseradish peroxidase(WGA-HRP) into the rat intestine. The tracers were injected in the stomach(anterior and posterior portion), duodenum, jejunum, ileum, cecum, ascending colon or descending colon. After survival times of 48-96 hours, the rats were perfused and their brain, spinal and nodose ganglia were frozen sectioned(40microM). These sectiones were stained by CTB immunohistochemical and HRP histochemical staining methods and observed by dark and light microscopy. The results were as follows: 1. WGA-HRP labeled afferent terminal fields in the brain stem were seen in the stomach and cecum, and CTB labeled afferent terminal fields in the brain stem were seen in all parts of the intestine. 2. Afferent terminal fields innervating the intestine were heavily labeled bilaterally gelalinous part of nucleus of tractus solitarius(gelNTS), dorsomedial part of gelNTS, commissural part of NTS(comNTS), medial part of NTS(medNTS), wall of the fourth ventricle, ventral border of area postrema and comNTS in midline dorsal to the central canal. 3. WGA-HRP labeled sensory neurons were observed bilaterally within the spinal ganglia, and labeled sensory neurons innervating the stomach were observed in spinal ganglia T2-L1 and the most numerous in spinal ganglia T8-9. 4. Labeled sensory neurons innervating the duodenum were observed in spinal ganglia T6-L2 and labeled cell number were fewer than the other parts of the intestines. 5. Labeled sensory neurons innervating the jejunum were observed in spinal ganglia T6-L2 and the most numerous area in the spinal ganglia were T12 in left and T13 in right. 6. Labeled sensory neurons innervating the ileum were observed in spinal ganglia T6-L2 and the most numerous area in the spinal ganglia were T11 in left and L1 in right. 7. Labeled sensory neurons innervating the cecum were observed in spinal ganglia T7-L2 and the most numerous area in the spinal ganglia were T11 in left and T11-12 in right. 8. Labeled sensory neurons innervating the ascending colon were observed in spinal ganglia T7-L2 in left, and T9-L4 in right. The most numerous area in the spinal ganglia were T9 in left and T11 in right. 9. Labeled sensory neurons innervating the descending colon were observed in spinal ganglia T9-L2 in left, and T6-L2 in right. The most numerous area in the spinal ganglia were T13 in left and L1 in right. 10. WGA-HRP labeled sensory neurons were observed bilaterally within the nodose ganglia, and the most numerous labeled sensory neurons innervating the abdominal organs were observed in the stomach. 11. The number of labeled sensory neurons within the nodose ganglia innervating small and large intestines were fewer than that of labeled sensory neurons innervating stomach These results indicated that area of sensory neurons innervated all parts of intestines were bilaterally gelatinous part of nucleus tractus solitarius(gelNTS), dorsomedial part of gelNTS, commissural part of NTS(comNTS), medial part of NTS, wall of the fourth ventricle, ventral border of area postrema and com NTS in midline dorsal to the central canal within brain stem, spinal ganglia T2-L4, and nodose ganglia. Labeled sensory neurons innervating the intestines except the stomach were observed in spinal ganglia T6-L4. The most labeled sensory neurons from the small intestine to large intestine came from middle thoracic spinal ganglia to upper lumbar spinal ganglia.

ORIGIN OF SOMATOSTATIN POSITIVE FIBERS IN THE RAT POSTERIOR PITUITARY / 解剖学报

WGA-HRP retrograde tracing technique combined with immunohistochemical method was used to study the source of somatostatin postitive fibers in the posterior pituitary. Retrogradely labeled somatostatin immunoreactive cells distributed mainly in the periventricular area from the level of the anterior to posterior magnocellular paraventricular nucleus; single double labeled cells were also found in the periventricular areas at the level of the anterior commissure and posterior fornical nucleus. A few double labeled cells were seen in medial parvocellular paraventricular nucleus and the medial part of posterior magnocelluar paraventricular nucleus. The double labeled cells in the periventricular area lie mainly beneath the ependymal layer. Some were seen to intercalated in-between the ependymal cells, bringing themselves very close to the cerebrospinal fluid, but no direct fluid contacing elements were verified.

CONNECTIONS OF THE OVAL NUCLEUS AND ITS ADJACENT AREAS OF THE BED NUCLEI OF THE STRIA TERMINALIS IN THE RAT. AFFERENT CONNECTIONS——A FLUOROGOLD AND WGA-HRP RETROGRADE TRACT-TRACING STUDY / 解剖学报

The present experiments were designed to study the afferent connections of the oval nucleus (Ov) of the bed nuclei of the stria terminalis (BST) using fluoro-gold (FG) and WGA-HRP as retrograde tracers. After injection of FG or WGA-HRP into the Ov area of the male SpragueDawley rats, a number of retrogradely labeled neurons were observed in the piriform cortex, fundus striati, subiculum, preoptie areas, horizontal limb of the diagonal band, ventral pallidum, magnocellular preoptic area, central (Ce), medial and cortical nuclei of the amygdala. A few neurons in the midline nuclei of the thalamus. were labeled. Many labeled neurons were found in the anterior, dorsal and lateral hypothalamic areas, ventral medial, arcuate and premammillary nuclei of the hypo thalamus. In the brainstem many labeled neurons were seen in the ventral part of the midbrain central gray, dorsal raphe nucleus, pedunculopontine tegmental nucleus, ventral tegmental area, compact zone of the substantia nigra, interpeduncular nuclei, interfascicular nucleus, raphe nuclei, parabrachial nuclei, locus coeruleus, mesencephalie trigeminal nucleus, dorsal vagal complex, A_5 and A_1 cell groups.In general, the distribution patterns of the labeled neurons of both tracers were quite similar except that FG labeled neurons showed much longer processes than WGA-HRP's, and some FG labeled neurons were also found in a few contralateral structures, such as central and medial nuclei of the amygdala and the horizontal limb of the diagonal band, where no WGA-HRP labeled neurons were observed.The results of this retrograde tract-tracing study together with our previous. anterograde tract-tracing study indicate that there are reciprocal connections between the Ov and the Ce, posterior part of the lateral hypothalamus and several brainstem structures.

AFFERENT CONNECTIONS FROM THE CEREBRAL CORTEX TO THE PREFRONTAL CORTEX IN THE RAT——A WGA-HRP STUDY / 解剖学报

The afferent projections of the prefrontal cortex(PFC) from the cerebral cortex were studied using WGA-HRP technique in 25 rats. The PFC of the rat re- cieved the afferent projections widely arising from the frontal, parietal,temporal, occipital, cingulate, piriform and retrohippocampal cortex. Furthermore,the dif- ferent organizations of the cortical afferent projections of the medial and lateral part of the PFC were also found. Besides the afferents from the somatic and visceral sensory cortex, the PFC of rat also recives afferents of visual and auditory cortex and it appears to be a multiple sensory convergence area.

THE AFFERENT PROJECTIONS OF THE HABENULAR NUCLEI IN THE RAT——A WGA-HRP STUDY / 解剖学报

WGA-HRP was iontophoretically delivered into the habenular nuclei in 40 rats to observe the distribution of the retrograde labeled cells; and into the entopeduncular nucleus(EPN), lateral preoptic area(LPO), medial preoptic area(MPO), nucleus septalis fimbriatis(SF), nucleus triangularis septi(TS), nucleus tractus diagonalis (Broca)(DBN)and lateral hypothalamic area(LHA) in 12 rats to observe the distribution of the orthograde labeled fibers in the habenular nuclei. It was found that the afferents of various parts of the habenular nuclei were different.The lateral habenular nucleus mainly recieves the afferents from the EPN, LPO and LHA, and the medial habenular nucleus from the SF, TS and LHA. Furthermore, the lateral habenular nucleus can be divided into medial and lateral parts, the medial habenular nucleus can be divided into medial and lateral parts as well, their afferent connections are also different.

SPINAL PROJECTIONS TO THE PARABRACHIAL NUCLEUS IN THE RAT——HRP AND FLUOROGOLD RETROGRADE TRACT TRACING STUDY / 解剖学报

By introducing a mixture of WGA-HRP and HRP or fluorogold into the parabrachial nucleus, the cell origin of the spinoparabrachial projections in the rat have been carefully examined. The labelled neurons were found in bilateral spinal gray matter, lateral spinal nucleus and lateral cervical nucleus with contralateral predominance. They were mainly located in lamina I, lamina II, lamina IV, lamina V and lamina VII of the gray matter and also in the gray matter commissure posterior to the central canal. Comparing the distribution patterns of the projection neurons in the cervical, thoracic, lumbar and sacral segments, we did not find any distinct differences. The fact that the parabrachial nucleus receives a wide extensive projections form the spinal segments suggests that the spino-parabrachial pathways are possibly involved in the transmission of multiple sensory inputs.

EFFERENT CONNECTIONS OF THE OVAL NUCLEUS AND ITS ADJACENT AREAS OF THE BED NUCLEII OF THE STRIA TERMINALIS IN THE RAT——A WGA-HRP ANTEROGRADE TRACING STUDY / 解剖学报

Ju and Swanson first named the dorsal part of the anterolateral area of the bed nuclei of the stria terminalis (BST) as oval nucleus (Ov), and found that it was a homogeneous structure rich in neuropeptide-containing neurons and terminals. However, no systemic study has been made about the connections of the Ov.The present experiments were designed to examine the efferent projections of the Ov in the rat. Wheat germ agglutinin conjugated horseradish peroxidase(WGA-HRP) was used as a tracer.Injection of WGA-HRP into the Ov and its adjacent areas resulted in dense anterograde labelling in the posterior part of the lateral hypothalamic area, central nucleus of the amygdala, ventral part of the midbrain central gray, ventral tegmental nucleus, parabrachial nuclei, mesencephalic trigeminal nucleus and locus coeruleus; moderate labelling in the preoptic area, periventricular area of the hypothalamus, arcuate nucleus of the hypothalamus, midline nuclei of the thalamus, medial habenular nucleus, pedunculopontine tegmental nucleus, midbrain reticular formation, dorsal raphe nucleus and the dorsal vagal complex; sparse labelling in the caudal linier nucleus, median raphe nucleus, ventral tegmental area, substantia nigra and intercalated nucleus of medulla oblongata. The results suggest that the Ov may be involved in multiple physiological functions.

EFFERENT CONNECTIONS OF THE DORSOMEDIAL NUCLEUS OF THALAMUS IN THE RAT WITH WGA-HRP METHOD / 解剖学报

WGA-HRP was injected into the dorsomedial nucleus of thalamus (DM)by means of microiontophoretical delivery in 19 rats, and into the dorsal division of anterior cingulate cortex (ACd), the prelimbic area (PL), the dorsal agranular insular area (AId) of prefrontal cortex by using microinjective system in 17 rats to observe the efferent projections of the DM.It was found that the DM projected to a large part of the prefrontal cortex including the medial precentral area (PCm), ACd, PL, AId, ventral agranular insular area (AIv), medial orbital area (MO), ventral orbital area (VO), ventrolateral orbital area (VLO), and some topographical organizations were also found. The lateral segment of DM projects to the ACd, PCm, PL, AId, AIv and VLO. The intermediate segment of DM projects to the AId and AIv. The medial segment of DM projects to the AId, PL, IL, AIv, MO and VO. Furthermore, the DM also projects to some subcortical nuclei, such as the reticular nucleus of thalamus (R), the lateral preoptic area (LPO), the lateral hypothalamic area (LHA), the caudoputamen, the nucleus accumbens and the parafascicular nucleus of thalamus. In addition, some reciprocal connections between the DM and the ACd, PCm, PL, IL, AId, R, LPO and LHA were observed.

AFFERENT CONNECTIONS OF THE DORSOMEDIAL NUCLEUS OF THE THALAMUS IN THE RAT WITH WGA-HRP METHOD / 解剖学报

WGA-HRP was injected into different segment of the dorsomedial nucleus (DM) of thalamus by means of microiontophoretical delivery in 19 rats to observe the afferent projections of DM. It is found that the DM received afferent projections widely from the frontal cortex, basal telecephalon, limbic system, monoaminergic neuron, reticular formation, central gray matter and superior colliculus. Furthermore, some topographical organization has also been observed. The medial segment of DM received afferent projections mainly from dorsal agranular insular cortex, infralimbic cortex, amygdaloid complex, septum, bed nucleus of the stria terminalis and raphe nuclei, related with the function of the limbic system. The central segment of DM received afferent projections from the dorsal agranular insular cortex and the prepiriform cortex, also related with the function of the limbic system. The lateral segment of DM received afferent projections mainly from the medial precentral cortex, dorsal division of anterior cingulate cortex, E-W nucleus and superior colliculus, related with the function of eye movement. In addition, all the three segments of DM received numerous afferents from the substantia innominata, nucleus tractus diagonalis (Broca), lateral preoptic area and reticular nucleus of the thalamus.

ULTRASTRUCTURE OF THE DESCENDING RUBRAL FIBERS IN LAMINA V OF THE CAT TRIGEMINAL SUBNUCLEUS CAUDALIS——HRP LABELING AND DEGENERATION STUDY / 解剖学报

After a injection of kainic acid or WGA-HRP into the red nucleus, the degenerated or HRP labeled terminals in lamina V of the contralateral trigeminal subnucleus caudalis (Vc) were examined electron microscopically. It was found that the degenerated and HRP labeled terminals contained vesicles of spherical or mixed type, and formed symmetrical synapses with medium- or small-sized dendrites. These findings suggested that the descending rubral fibers might be inhibitory in regulating the activity of the neurons, and supposed to be sensory in nature. Thus the red nucleus might play certain role in modulation of the oro-facial somatosensory transmission (including pain) in lamina V of Vc, besides the rubrospinal influence on the involuntary motor functions of the spinal anterior horn. The technique for tracing neural connections with electron microscope was discussed as well.

THE NON-AUDITORIAL AFFERENTS OF THE INFERIOR COLLICULUS IN THE RAT——WGA-HRP METHOD / 解剖学报

WGA-HRP was injected into the inferior colliculus in the rat in order to study the non-auditorial afferents of the inferior colliculus. In the diencephalon and truncus encephali, retrograde labeling was observed in many non-auditorial regions: bilateral (with contralateral predominance) cuneate nucleus, gracile nucleus, nucleus of spinal tract of trigeminal nerve, nucleus medullae oblongatae centralis dorsalis; bilateral (with homolateral predominance) locus ceruleus, nucleus reticularis pontis oralis, laterodorsal tegmental nucleus, substantia nigra, sub-parafascicular nucleus, perifornical nucleus; bilateral medial parabrachial nucleus, deep tegmental nucleus of midbrain, lateral hypothalamic area; homolateral deep layer of superior colliculus, zona incerta; contralateral nucleus of solitary tract; and posteromedian septum, central tegmental nucleus, dorsal nucleus of the raphe. The afferent neurons from cuneate nucleus, gracile nucleus, nucleus of spinal tract of trigeminal nerve, nucleus of solitary tract mainly located below the level of obex. The results mentioned above suggested that the inferior colliculus is not only an auditorial relay nucleus, but also a complex body which is of different functions.

THE EFFERENT PROJECTIONS OF THE HABENULAR NUCLEI IN THE RAT---A WGA-HRP STUDY / 解剖学报

WGA-HRP was iontophoretically delivered into various parts of the habenular nuclei (the lateral segment of the lateral habenular nucleus LHb-L, the medial segment of the lateral habenular nucleus LHb-M, and the medial habenular nucleus MHb) in 40 rats to study the route and distribution of the anterograde labeled fibers and terminals in the brain. The efferent projections of the habenular nuclei follow three routes, the rostral, contralateral and caudal pathways. Along the rostral pathway fibers leave the lateral habenular nucleus, follow the stria medullaris thalami rostrally, and distribute to the thalamic dorsomedial nucleus, paratenial nucleus and lateral preoptic area. Fibers from the contralateral pathway distribute to the opposite lateral habenular nucleus by way of the commissura habenularum Fibers in the caudal pathway originate mainly from the MHb and LHb-M, and distribute to the interpeduncular nucleus with a dorsoventral topographic localization. In addition some of the caudal efferent fibers run caudally and terminate in the raphe nuclei and reticular formation etc.

AFFERENT PROJECTIONS FROM THE DIENCEPHALON AND SUBCORTICAL TELENCEPHALON TO THE PREFRONTAL CORTEX IN THE RAT——A WGA-HRP STUDY / 解剖学报

WGA-HRP was injected into the dorsal part of anterior cingulate area,prelim- bic area,and dorsal agranular insular area of the prefrontal cortex in 25 rats to observe the afferent connections from the diencephalon and subcortical telencephalon. The afferent projections from the diencephalon mainly originate from the dorsome- dial nucleus of the thalamus,and some topographic localization may exist.Further- more,the afferent projections to the prefrontal cortex arise from the thalamic intralaminar nuclei(centrolateral nucleus,paracentral nucleus,centromedial nucleus and parafascicular nucleus),the ventral thalamic nuclei(ventrolateral nucleus,ven- tromedial nucleus,ventroanterior nucleus and ventroposterior nucleus),the midline nuclei(rhomboid nucleus,reuniens nucleus,paratenial nucleus,and paraventricular nucleus of the thalamus),the anteromedial nucleus,the lateral habenular nucleus, the posterior nucleus of the thalamus,and the lateral nucleus of the thalamus.The numbers projecting to the prefrontal cortex were different in different thalamic nuclei.The afferent projections from the hypothalamus mainly originate from the lateral hypothalamic area,lateral preoptic area,caudal magnocellular nucleus,and supramamillary nucleus.A few of afferent projections from the posterior hypothala- mic area,dorsomedial and ventromedial nucleus of the hypothalamus and zona inserta were also observed.The afferent projections from the subcortical telence- phalon mainly originate from the globus pallidus,the diagonal band nucleus,the septal nuclei(medial septal nucleus,lateral septal nucleus,septofimbrial nucleus and nucleus triangularis septi),the amygdaloid nuclei(lateral amygdaloid nucleus,lateral and medial part of basal amygdaloid nucleus,medial amygdaloid nucleus and cortical amygdaloid nucleus)and the claustrum.

THE EFFERENT PROJECTIONS OF THE SUPERIOR COLLICULUS IN THE RAT.A STUDY WITH ARG AND WGA-HRP TECHNIQUES / 解剖学报

In the present study ~3H-Leucine or WGA-HRP was injected into the superior colliculus of one side in the rat.The terminal areas of the efferent projection fibers from the superior colliculus were examined. The efferent fibers of the superfical layer of the superior colliculus descended ipsilaterally to terminate in the parabigeminal nucleus(predominantly the dorsal and ventral part of the same side)and dorso-lateral part of the ipsilateral pontine nucleus.Ascending projections terminated to the medial geniculate nucleus,the posterior pretectal nucleus and latero-posterior nucleus of the thalamus(all bila- terally,but with ipsilateral predominance),the ipsilateral medial and lateral optic nuclei,and the dorsal and ventral lateral geniculate nucleus.In addition,labeled granules were also found in bilateral optic tracts and the optic chiasma. The efferent fibers of the middle and deep layers terminated to the ipsilateral central gray,the nucleus of Darkschewitsch,the interstitial nucleus of Cajal,the cuneiform nucleus and the contralateral superior colliculus.Ascending fibers ter- minated to the medial geniculate nucleus,the suprageniculate nucleus,the anterior- pretectal nucleus,the postero-lateral nucleus of the thalamus(all bilaterally,but more on the ipsilateral side),the parafascicular nucleus,the zona incerta,the ventral nucleus of the thalamus(all ipsilaterally).Descending fibers terminated to ipsilateral parabigeminal area and the parabigeminal nucleus,the dorso-lateral part of the pontine nucleus,the lateral part of the inferior colliculus,the reticular formation of the medulla oblongata and pons,and the lateral part of the inferior olive.The fibers terminated also to contralateral nuclei such as the parabigeminal nucleus,the medial part of the reticular formation of the medulla oblongata and ports,the medial accessory nucleus of the inferior olive,the anterior horn of the cervical spinal cord.