Cortico-cortical and subcortico-cortical afferent connections of the rabbit''s primary visual cortex

Summary Neuroanatomical studies were carried out on the visual system of the adult rabbit brain. Either horseradish peroxidase (HRP) or wheat germ agglutinine-horseradish peroxidase (WGA-HRP) was injected into the area occipitalis 1. Several cortico-cortical, ipsi- and contralateral, and subcortico-cortical projections were demonstrated.In the ipsilateral telencephalon several patches of labelled cell groups, some single HRP-positive cell bodies and some labelled fibres were observed in the area retrosplenialis granularis dorsalis, the areas occipitales, the areas temporales, the area perirhinalis, the area entorhinalis, the area praecentralis 1, the regio cingularis 1 and in the regio diagonalis, as well as in the dorsal part of the claustrum. Efferent preterminal fibres and terminal knobs were seen in the nucleus caudatus. Contralaterally, groups of labelled cell bodies and single HRP-positive neurons were found in the area retrosplenialis granularis dorsalis, the areas occipitales and the areas temporales.In the ipsilateral diencephalon, labelled cell bodies were observed in the corpus geniculatum laterale (pars dorsalis and ventralis), the nucleus lateralis thalami, the nucleus reticularis thalami and in nonspecific nuclei of the midline. Contralaterally, very few labelled cell bodies were seen in the nonspecific nuclei of the midline.Some labelled cell bodies were observed in the ipsilateral substantia griseum centrale and in the nucleus reticularis mesencephali. Numerous anterogradely labelled preterminal fibres and terminal knobs but very few labelled cell bodies were seen in the nucleus praetectalis posterior. In the nucleus of the optic tract and in the colliculus superior, numerous labelled fibres could be observed.In the ipsilateral nuclei pontis numerous labelled fibres were detectable.     

The reticulocerebellar projection in the cat as studied with retrograde transport of horseradish peroxidase

Summary Injections of horseradish peroxidase into the various parts of the cerebellar cortex and the cerebellar nuclei in the cat result in labelled cells within the reticular formation proper. All the reticular nuclei (with the exception of the reticular formation of the mesencephalon) send fibres to the cerebellum. The highest number of labelled neurons after cerebellar injections is found in the caudal reticular formation, especially within nucleus reticularis ventralis, nucleus reticularis lateralis and nucleus reticularis gigantocellularis. Another region for an accumulation of labelled cells is the rostral part of nucleus reticularis pontis caudalis.Except for the paraflocculus, all cerebellar cortical areas and all cerebellar nuclei receive afferents from one or more of the nuclei within the reticular formation proper, but the largest number of labelled neurons is observed in cases with injections including the intermediate-lateral part of lobulus simplex and the adjacent areas of the anterior lobe and crus I. The projection is bilateral with an ipsilateral preponderance (the cerebellar nuclei appear to receive a higher number of fibres from the contralateral side). Cells of all sizes are labelled, but labelled giant cells are found only after large cortical injections.     

黄喉鹀耳蜗核的传出投射

用HRP顺行追踪方法,研究黄喉鵐(emberiza elegans)的两对耳蜗核,即角状核和巨细胞核的传出投射.将HRP注入角状核,在双侧上橄榄核,对侧外侧丘系核腹侧部,外侧丘系腹核及中脑背外侧核的背侧1/4的区域见到顺行标记纤维或终末.将HRP注入巨细胞核,标记纤维或终末分布于双侧层状核;标记细胞分布于同侧上橄榄核.结果表明:角状核投射至双侧上橄榄核,对侧外侧丘系核腹侧部,外侧丘系腹核及中脑背外侧核的背侧部.巨细胞核投射至双侧层状核.此外,巨细胞核接受同侧上橄榄核的传人,它可能是一条听觉的反馈回路.     

An immunocytochemical mapping of ACTH/CLIP in the cat diencephalon

Using an indirect immunoperoxidase technique, the location of cell bodies and fibres containing adrenocorticotropin hormone/corticotropin-like intermediate lobe peptide (ACTH/CLIP) was studied in the cat diencephalon. Immunoreactivity was observed in several diencephalic nuclei of the cat in which no immunoreactivity has been previously reported. In this sense, a low density of immunoreactive cell bodies was found in the nucleus ventromedialis hypothalami; a high density of immunoreactive fibres was found in the medial preoptic area; a moderate density in the lateral preoptic area and in the nuclei centralis thalami (pars medialis), interventralis thalami, interanteromedialis thalami, parafascicularis and praemamillaris (pars ventralis and pars dorsalis); a low density in the nuclei habenularis lateralis and reuniens thalami, and single fibres were found in the nuclei lateralis thalami (pars anterior), habenularis medialis, parataenialis, corpus geniculatum mediale, ventralis thalami (pars medialis) and in the fornix. Our results point to a more widespread distribution of ACTH/CLIP immunoreactive structures in the cat diencephalon in comparison with previous studies carried out in the same region of this feline.     

黄喉鹀听觉通路的研究——中脑外侧核背部的中枢联系

向黄喉鹀一侧中脑外侧核背侧部微电泳导入HRP后.在同侧脑桥外侧丘系腹核,外侧丘系核腹侧部,对侧上橄榄核,延髓层状核及角状核等处见到逆标细胞,在同侧丘脑卵圆核及卵圆核腹内侧部脑桥外侧丘系腹核出现了标记终末,在对侧中脑外侧核背侧部有密布的标记细胞及终末.结果表明:中脑外侧核背侧部接受脑桥外侧丘系核复合体的外侧丘系核腹侧部及上橄榄核、延髓层状核及NA的传入投射,MLd的纤维传出投射至丘脑的卵圆核及卵圆核腹内侧部,双侧中脑外侧核背侧部之间有往返联系.     

大鼠下丘的非听性传出投射

为了全面了解大白鼠下丘的非听性传出投射及其起源细胞在下丘的分布情况,作者分别向下丘、丘脑和延髓注入WGA-HRP,作顺行或逆行追踪研究,结果如下: 下丘的非听性传出投射分布较广,在间脑和脑干终止于12个核团和地区,包括同侧的桥核背外侧部、臂旁外侧核、中脑中央灰质、中脑外侧被盖核、上丘联合核、顶盖前区、丘脑网状核、膝上核、丘脑后核、丘脑腹核、未定带和对侧楔束核的背外侧部。上述非听性传出投射的起源细胞分布于下丘除中央核以外的其他亚核。     

Distribution of methionine-enkephalin in the minipig brainstem

We have studied the distribution of immunoreactive cell bodies and axons are containing methionine-enkephalin in the minipig brainstem. Immunoreactive axons were widely distributed, whereas the distribution of perikarya was less widespread. A high or moderate density of axons containing methionine-enkephalin were found from rostral to caudal levels in the substantia nigra, nucleus interpeduncularis, nucleus reticularis tegmenti pontis, nucleus dorsalis raphae, nucleus centralis raphae, nuclei dorsalis and ventralis tegmenti of Gudden, locus ceruleus, nucleus sensorius principalis nervi trigemini, nucleus cuneatus externalis, nucleus tractus solitarius, nuclei vestibularis inferior and medialis, nucleus ambiguus, nucleus olivaris inferior and in the nucleus tractus spinalis nervi trigemini. Immunoreactive perikarya were observed in the nuclei centralis and dorsalis raphae, nucleus motorius nervi trigemini, nucleus centralis superior, nucleus nervi facialis, nuclei parabrachialis medialis and lateralis, nucleus ventralis raphae, nucleus reticularis lateralis and in the formatio reticularis. We have also described the presence of perikarya containing methionine-enkephalin in the nuclei nervi abducens, ruber, nervi oculomotorius and nervi trochlearis. These results suggest that in the minipig the pentapeptide may be involved in many physiological functions (for example, proprioceptive and nociceptive information; motor, respiratory and cardiovascular mechanisms).     

Neurotransmitter characteristics of neurons projecting to the supramammillary nucleus of the rat

Retrograde labelling was combined with immunohistochemistry to localize neurons containing choline acetyltransferase, gamma-aminobutyric acid (GABA), glutamate, serotonin, somatostatin, Leu-enkephalin, neurotensin, and substance P-immunoreactivity in neurons projecting to the supramammillary nucleus in the rat. Injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the supramammillary nucleus resulted in retrogradely labelled neurons in the medial septal nucleus, the nuclei of the diagonal band of Broca, the infralimbic cortex, the medial and lateral preoptic nucleus, the subiculum, the laterodorsal tegmental nucleus, the compact subnucleus of the central superior nucleus and the dorsal raphe nucleus. In the medial septal nucleus and in the nuclei of the diagonal band of Broca, 80-85% of WGA-HRP- labelled neurons (30-40 per section) were also immunoreactive for choline acetyltransferase and small numbers of WGA-HRP-labelled neurons were immunoreactive for GABA, glutamate, neurotensin or substance P. In the medial preoptic nucleus, 85-90% of retrogradely labelled neurons (25-30 per section) were immunoreactive for somatostatin and a few WGA-HRP-labelled neurons displayed neurotensin-immunoreactivity. In the rostroventral part of the subiculum, small numbers of retrogradely labelled neurons were also immunoreactive for neurotensin or for glutamate. In the laterodorsal tegmental nucleus, 90% of WGA-HRP-labelled neurons (20-25 per section) were immunoreactive for choline acetyltransferase and small numbers of retrogradely labelled neurons also displayed substance P immunoreactivity. In the compact subnucleus of the central superior nucleus, 50-60% of retrogradely labelled neurons (15-20 per section) were also immunolabelled for GABA and approximately 30-40% of WGA-HRP-labelled neurons (10-12 per section) were immunoreactive for Leu-enkephalin. The compact subnucleus of the central superior nucleus also contained small numbers of retrogradely labelled neurons that displayed neurotensin immunoreactivity. In the dorsal raphe nucleus, 80-85% of WGA-HRP- labelled neurons (30-40 per section) were also immunoreactive for serotonin and small numbers of retrogradely labelled neurons displayed neurotensin or glutamate immunoreactivity. These results suggest that the multiple neurochemicals contained in ascending and descending projections to the SuM participate in complex interactions in the transmission process of SuM neurons.     

大白鼠脑干至腰骶髓投射的生后发育——HRP法研究

本实验用生后1、3、5、7至35天的大白鼠18只,将50％的HRP液注入右侧脊髓腰膨大内。HRP标记细胞见于下列核团:1.中脑:红核、黑质和中缝背核。2.脑桥:脑桥吻侧网状核、脑桥尾侧网状核、蓝斑、蓝斑下核、中缝大核、前庭神经外侧核和前庭神经内侧核。3.延髓:中缝隐核、中缝苍白核、腹侧网状核、巨细胞网状核、网状外侧核、三叉神经脊束核、Cajal连合核、前置核和薄束核。各核团标记细胞数随动物的生后发育逐渐增多。表明大白鼠脑干至腰骶髓投射有一生后发育过程。红核脊髓束和蓝斑脊髓投射较网状脊髓束和前庭脊髓束成熟得晚一些。脑干至腰骶髓的投射约于生后1个月完成。     

Brain stimulation-induced changes of phonation in the squirrel monkey

Summary In 11 squirrel monkeys (Saimiri sciureus), the brain stem was systematically explored with electrical brain stimulation for sites affecting the acoustic structure of ongoing vocalization. Vocalization was elicited by electrical stimulation of different brain structures. A severe deterioration of the acoustical structure of vocalization was obtained during stimulation of the caudoventral part of the periaqueductal grey, lateral parabrachial area, corticobulbar tract, nucl. ambiguus and surrounding reticular formation, facial nucleus, hypoglossal nucleus, solitary tract nucleus and along the fibres crossing the midline at the level of the hypoglossal nucleus. It is suggested that these structures are part of, or at least have direct access to, the motor coordination mechanism of phonation. Complete inhibition of phonation was obtained from the raphe and raphe-near reticular formation.Abbreviations Ab nucl ambiguus - APt area praetectalis - BC brachium conjunctivum - BP brachium pontis - Cb cerebellum - CC corpus callosum - Cd nucl. caudatus - Cf nucl. cuneiformis - Cel nucl. centralis lateralis - Cl claustrum - CM centrum medianum - Cn nucl. cuneatus - Co nucl. cochlearis - CoI colliculus inferior - CoS colliculus superior - CP commissura posterior - CPf cortex piriformis - CRf corpus restiforme - CSL nucl. centralis superior lateralis thalami - CT corpus trapezoideum - DBC decussatio brachii conjunctivi - DG nucl. dorsalis tegmenti (Gudden) - DLM decussatio lemnisci medialis - DPy decussatio pyramidum - DR nucl. dorsalis raphae - DV nucl. dorsalis n. vagi - DIV decussatio n. trochlearis - EP epiphysis - FC funiculus cuneatus - FL funiculus lateralis - FLM fasciculus longitudinalis medialis - FRM formatio reticularis myelencephali - FRP formatio reticularis pontis - FRPc formatio reticularis pontis caudalis - FRPo formatio reticularis pontis oralis - FRTM formatio reticularis mesencephali - FV funiculus ventralis - G nucl. gracilis - GC substantia grisea centralis (periaqueductal grey) - GL nucl. geniculatus lateralis - GM nucl. geniculatus medialis - GP globus pallidus - GPM griseum periventriculare mesencephali - GPo griseum pontis - Hip hippocampus - HL nucl. habenularis lateralis - H habenula - IP nucl. interpeduncularis - LC locus coeruleus - LD nucl. lateralis dorsalis thalami - Lim nucl. limitans - LLd nucl. lemnisci lateralis, pars dorsalis - LLv nucl. lemnisci lateralis, pars ventrali - LM lemniscus medialis - LP nucl. lateralis posterior thalami - MD nucl. medialis dorsalis thalami - MV nucl. motorius n. trigemini - NCS nucl. centralis superior - NCT nucl. trapezoidalis - NMV nucl. mesencephalicus n. trigemini - NR nucl. ruber - NSV nucl. spinalisn. trigemini - NTS nucl. tractus solitarii - NIII nucl. oculomotorius - NIV nucl. trochlearis - NVI nucl. abducens - NVII nucl. facialis - NXII nucl. hypoglossus - OI oliva inferior - OS oliva superior - P nucl. posterior thalami - PbL nucl. parabrachialis lateralis - PbM nucl. parabrachialis medialis - PC depedunculus cerebri - Pd nucl. peripeduncularis - Pg nucl. parabigeminalis - Pp nucl. praepositus - PuI nucl. pulvinaris inferior - PuL nucl. pulvinaris lateralis - PuM nucl. pulvinaris medialis - PuO nucl. pulvinaris oralis - Py tractus pyramidalis - Pv nucl. principalis n. trigemini - R Ab nucl. retroambiguus - RL nucl. reticularis lateralis - RTP nucl. reticularis tegmenti pontis - Sf nucl. subfascicularis - SGD substantia grisea dorsalis - SGV substantia grisea ventralis - SN substantia nigra - ST stria terminalis - St subthalamus - TRM tractus retroflexus (Meynert) - TSc tractus spinocerebellaris - Ves nucl. vestibularis - VL nucl. ventralis lateralis - VPI nucl. ventralis posterior inferior - VPL nucl. ventralis posterior lateralis - VPM nucl. ventralis posterior medialis - VR nucl. ventralis raphae - Zi zona incerta - II tractus opticus - VII n. facialis     

家兔网状脊髓束的起源

本实验用HRP轴突逆行传递法,观察了27只家兔网状脊髓束的起源。实验结果表明,网状脊髓束的起源较为广泛,包括网状结构內侧区、外侧区、中脑网状结构和旁正中网状核,不同核团的标记细胞,数目不等。脊髓不同部位,分别导入HRP时,结果不同,颈體注射例,标记细胞最多的是延體中央腹侧核。腰體注射例,标记细胞最多的是巨细胞网状核。胸髓注射例,网状脑桥尾侧核和脑桥网状嘴侧核中的标记细胞相对增多。在颈髓注射例中,网状结构各核均出现标记细胞。但在腰髓注射例,部分网状结构中的核团无标记细胞。     

Olivary afferents from the brain stem reticular formation

Summary The projections from the brain stem reticular formation to the inferior olive have been studied in cats in which microinjections of horseradish peroxidase have been made into the inferior olive from a ventral approach. Retrogradely labelled cells were observed within the reticular formation proper of the medulla, pons and mesencephalon (within the nucleus reticularis parvicellularis, reticularis ventralis, reticularis gigantocellularis, reticularis lateralis, reticularis pontis caudalis, reticularis pontis oralis, cuneiformis and subcuneiformis). Labelled cells were also found within the lateral reticular nucleus (the nucleus of the lateral funiculus), the paramedian reticular and the perihypoglossal nuclei. The connections are bilateral (the projection from the lateral reticular nucleus is only contralateral). The observations demonstrate a more widespread origin for the reticulo-olivary fibres than has previously been shown and indicate that the medullary reticular formation is the area with the highest number of cells projecting to the olivary complex.Abbreviations ß nucleus ß - Br.c. superior cerebellar peduncle (brachium conjunctivum) - Br.p. middle cerebellar peduncle (brachium pontis) - C.i. inferior colliculus - C.r. inferior cerebellar peduncle (restiform body) - Cu nucleus cuneiformis - D dorsal accessory olive - dl dorsal lamella - dors.c. dorsal cap - dorsomed.c.col. dorsomedial cell column - F.l.m. medial longitudinal fasciculus - Ic or ic nucleus intercalatus - l lateral - M medial accessory olive - m medial - N.III,V,VI,VII,X,XII root fibres of cranial nerves - N.c. nucleus cuneatus - N.c.e. external (accessory) cuneate nucleus - N.c.t. nucleus of corpus trapezoideum - N.l.l. nucleus of lateral lemniscus - N.m.X dorsal motor (parasympathetic) nucleus of vagus - N.mes. mesencephalic trigeminal nucleus - Nr nucleus ruber - Nrl or N.r.l lateral reticular nucleus (nucleus of lateral funiculus) - Nrp or N.r.p. nucleus reticularis paramedianus - N.r.t. nucleus reticularis tegmenti pontis - nucl. nucleus ß - Ol.s. superior olive - P principal olive - ph or P.h. nucleus praepositus hypoglossi - PN perihypoglossal nuclei - Pp nucleus peripeduncularis - Py pyramid - Rg or R.gc. nucleus reticularis gigantocellularis - Rl or R.l. nucleus reticularis lateralis (of Olszewski) - Rp or R.pc. nucleus reticularis parvicellularis - Rpc or R.p.c. nucleus reticularis pontis caudalis - Rpo or R.p.o. nucleus reticularis pontis oralis - Rv or R.v. nucleus reticularis ventralis - Scu nucleus subcuneiformis - S.n. substantia nigra - Tr.sp.V. spinal tract of trigeminal nerve - T.s. tractus solitarius surrounded by nucleus of solitary tract - vl ventral lamella - vlo or ventrolat outgr. ventrolateral outgrowth - V.m. medial vestibular nucleus - I-XV transverse sections through the olive from caudal (I) to rostral (XV) - III,IV,V,VI,VII,X and XII motor nuclei of cranial nerves (X: nucleus ambiguus)     

Afferent fiber connections from lower brain stem to hypothalamus studied by the horseradish peroxidase method with special reference to noradrenaline innervation

Summary Attempts were made to determine the afferent projections to the anterior hypothalamus including the preoptic area from the lower brain stem by means of the horseradish peroxidase method combined with monoamine oxidase staining to identify noradrenaline (NA) neurons. In addition to this technique, a histofluorescence analysis was performed. NA fibers in the medial part of the anterior hypothalamus were mainly supplied by A1 and A2 NA neuron groups, while the lateral part and periventricular zone received NA terminals from both pontine and medulla oblongata NA neuron groups. Furthermore, the present study indicated that there were direct projections to the anterior hypothalamus from non-noradrenergic neurons in the lower brain stem: nuclei raphe dorsalis, centralis superior, cells in the mesencephalic and pontine central gray matter, nuclei parabrachialis lateralis and medialis, cells around fasciculus longitudinalis medialis.Abbreviations CA Commissura anterior - CO Chiasma opticum - DP Decussatio pyramidum - DPCS Decussatio pedunculorum cerebellarium superiorum - F Columna fornicis - FLM Fasciculus longitudinalis medialis - FMT Fasciculus mamillothalamicus - GCM Griseum centrale mesencephali - GCP Griseum centrale pontis - LL Lemniscus lateralis - LM Lemniscus medialis - PCM Pedunculus cerebellaris medius - PCS Pedunculus cerebellaris superior - TO Tractus opticus - TS Tractus solitarius - TVme Tractus mesencephalicus nervi trigemini - V Ventriculus tertius - VTS Tractus spinalis nervi trigemini - am nucleus ambiguus - B Barrington nucleus - com nucleus commissuralis - cp nucleus caudatus putamen - cs nucleus centralis superior - ct nucleus corporis trapezoidei - cu nucleus cuneatus - dX nucleus dorsalis nervi vagi - Gd nucleus tegmentalis dorsalis (von Gudden) - gr nucleus gracilis - Gv nucleus tegmentalis ventralis (von Gudden) - ha nucleus hypothalamicus anterior - hl nucleus hypothalamicus lateralis - hpe nucleus periventricularis (hypothalami) - hvm nucleus ventromedialis hypothalami - lc nucleus locus coeruleus - oi nucleus olivaris inferior - p nucleus pontis - pa nucleus paraventricularis - pbl nucleus parabrachialis lateralis - pbm nucleus parabrachialis medialis - ph nucleus praepositus hypoglossi - pol nucleus preopticus lateralis - pom nucleus preopticus medialis - pop nucleus preopticus periventricularis - rd nucleus raphe dorsalis - re nucleus reuniens - rl nucleus reticularis lateralis - rm nucleus raphe magnus - ro nucleus raphe obscrus - sc nucleus suprachiasmaticus - so nucleus supraopticus - st nucleus interstitialis striae terminalis - td nucleus tractus diagonalis (Broca) - ts nucleus tractus solitarii - Vme nucleus mesencephalicus nervi trigemini - Vmo nucleus motorius nervi trigemini - Vts nucleus tractus spinalis nervi trigemini - XII nucleus nervi hypoglossi     

Evidence for collateral innervation of the cervical and lumbar enlargements of the spinal cord by single reticular and raphe neurons. Studies using fluorescent markers in double-labeling experiments on the North American opossum

The use of fluorescent markers in double-labeling experiments reveals the presence of reticular and raphe neurons in the opossum's brainstem which innervate both the cervical and lumbar enlargements of the spinal cord by way of axonal collaterals. Such neurons were mixed with those innervating either the cervical or lumber enlargement alone and were found within the nuclei reticularis medullae oblongatae dorsalis and ventralis, the nucleus reticularis gigantocellularis, the nucleus reticularis gigantocellularis pars ventralis, the nucleus reticularis pontis and the nuclei obscurus and magnus raphae. In some nuclei over 50% of the neurons projecting to the cervical enlargement also innervate lumbar levels.     

Distribution of serotonin-immunoreactivity in the brain of the pigeon (Columba livia)

The distribution of serotonin (5-HT)-containing perikarya, fibers and terminals in the brain of the pigeon (Columba livia) was investigated, using immunohistochemical and immunofluorescence methods combined with retrograde axonal transport. Twenty-one different groups of 5-HT immunoreactive (IR) cells were identified, 2 of which were localized at the hypothalamic level (periventricular organ, infundibular recess) and 19 at the tegmental-mesencephalic and rhombencephalic levels. Ten of the cell groups were situated within the region of the midline from the isthmic to the posterior rhombencephalic level and constituted the raphe system (nucleus annularis, decussatio brachium conjunctivum, area ventralis, external border of the nucleus interpeduncularis, zona peri-nervus oculomotorius, zona perifasciculus longitudinalis medialis, zona inter-flm, nucleus linearis caudalis, nucleus raphe superior pars ventralis, nucleus raphe inferior). The 9 other cell populations belonged to the lateral group and extended from the posterior mesencephalic tegmentum to the caudal rhombencephalon [formatio reticularis mesencephali, nucleus ventrolateralis tegmenti, ectopic area (Ec) of the nucleus isthmo-opticus (NIO), nucleus subceruleus, nucleus ceruleus, nucleus reticularis pontis caudalis, nucleus vestibularis medialis, nucleus reticularis parvocellularis and nucleus reticularis magnocellularis]. Combining the retrograde axonal transport of rhodamine β-isothiocyanate (RITC) after intraocular injection and immunohistofluorescence (fluoresceine isothiocyanate: FITC/5-HT) showed the centrifugal neurons (NIO, ec) to be immunonegative. Serotonin-IR fibers and terminals were found to be very broadly distributed within the brain and were particularly prominent in several structures of the telencephalon (archistriatum pars dorsalis, nucleus taeniae, area parahippocampalis, septum), diencephalon (nuclei preopticus medianus, magnocellularis, nucleus geniculatus lateralis pars ventralis, nucleus triangularis, nucleus pretectalis), mesencephalon-rhombencephalon (superficial layers of the optic tectum, nucleus ectomamillaris, nucleus isthmo-opticus and in most of the cranial nerve nuclei). Comparing the present results with those of previous studies in birds suggests some major serotonin containing pathways in the avian brain and clarifies the possible origin of the serotonin innervation of some parts of the brain. Moreover, comparing our results in birds with those obtained in other vertebrate species shows that the organization of the serotoninergic system in many regions of the avian brain is much like that found in reptiles and mammals.     

Trigeminal nociceptive neurons in the subnucleus reticularis ventralis. II. Ascending projection.

Ascending projection of trigeminal nociceptive neurons in the subnucleus reticularis ventralis (SRV) was studied in urethane/chloralose-anesthetized cats. Thalamic neurons having complex trigeminal receptive fields similar to those of SRV neurons were found in the intralaminar nuclei, i.e. nuclei centralis lateralis, centralis medialis and parafascicularis. About half of the SRV units tested were antidromically activated by electrical stimulation of the nucleus centralis lateralis. It was also found that a significant proportion of SRV units was antidromically activated by electrical stimulation of the mesencephalic reticular formation (MRF), and retrogradely labelled neurons were found in the SRV after HRP injection into the MRF. These findings suggest that SRV neurons relay trigeminal nociceptive inputs directly or indirectly via the MRF to the intralaminar nuclei.     

Cerebello-cortical linkage in the monkey as revealed by transcellular labeling with the lectin wheat germ agglutinin conjugated to the marker horseradish peroxidase

Summary 1. The possibility of a cerebellar linkage, via the thalamus with medial area 6 of the cerebral cortex was further explored in the present experiments (cf. preceding companion paper). 2. It was found that HRP conjugated to the lectin wheat germ agglutinin injected into motor cortical areas was transported beyond the thalamus to the contralateral intracerebellar nuclei when the survival time was 4–7 days. 3. It is suggested that the labeling in the deep cerebellar nuclei occurred via the thalamic relay where cerebellofugal fibre terminals had taken up the marker substance released by corticothalamic fibre terminals or by the retrogradely labeled thalamic perikarya. 4. In general, transcellular labeling of perikarya was weaker than retrograde labeling in the thalamic cells. Some of the nuclear zones in the cerebellum showed relatively dense granulations of the reaction product; in other zones only cells with few granules were seen, and large parts of the nuclei were not labeled at all. 5. The topography of secondary labeling in the cerebellar nuclei depended on the cortical injection sites. In all cases, most labeling was found in the contralateral dentate nucleus. The interposed nucleus received a fair amount of heavy labeling only in the precentral arm and face cases. Very little labeling was seen in the fastigial nucleus and in the cerebellar nuclei ipsilateral to the cortical injections. A somatotopic organization of secondary labeling was noted in the precentral cases with the face being represented caudally, the hindlimb rostrally and the arm between the face and the hindlimb representation. This is in agreement with previous anatomical and electrophysiological investigations. 6. These observations thus lend support to the conclusion that the SMA receives a transthalamic input not only from the basal ganglia but also from the cerebellum, especially from its lateral, neocerebellar portion.Abbreviations AI Nucleus interpositus anterior - CM Nucleus centrum medianum - CSL Nucleus centralis lateralis superior - D Nucleus dentatus - F Nucleus fastigius - I Nucleus interpositus - MD Nucleus medialis dorsalis - NRTP Nucleus reticularis tegmenti pontis - PI Nucleus interpositus posterior - PN Griseum pontis - SMA Supplementary motor cortex - STh Nucleus subthalamicus - VLc Nucleus ventralis lateralis, pars caudalis - VLo Nucleus ventralis lateralis, pars oralis - VPLo Nucleus ventralis posterior lateralis, pars oralis - X Nucleus X     

The vestibulothalamic projections in the cat studied by retrograde axonal transport of horseradish peroxidase

Summary Horseradish peroxidase (HRP) was injected or iontophoretically ejected in various thalamic nuclei in 63 adult cats. In 11 other animals HRP was deposited outside the thalamic territory. The number and distribution of labelled cells within the vestibular nuclear complex (VC) were mapped in each case. To a varying degree all subgroups of VC appear to contribute to the vestibulothalamic projections. Such fibres are distributed to several thalamic areas. From the present investigation it appears that generally speaking, there exist three distinct vestibulothalamic pathways with regard to origin as well as to site of termination of the fibres. One projection appears to originate mainly in caudal parts of the medial (M) and descending (D) vestibular nuclei and in cell group z. This pathway terminates chiefly in the contralateral medial part of the posterior nucleus of the thalamus (POm) including the magnocellular part of the medial geniculate body (Mgmc), the ventrobasal complex (VB) and the area of the ventral lateral nucleus (VL) bordering on VB. A second projection originates mainly in the superior vestibular nucleus (S) and in cell group y and terminates mainly in the contralateral nucleus centralis lateralis (CL) and the adjoining nucleus paracentralis (Pc). A third, more modest, pathway originates chiefly in the middle M and D, with a minor contribution from S and cell group y, and terminates in the contralateral ventral nucleus of the lateral geniculate body (GLV). There is some degree of overlap between the origin of these three vestibulothalamic pathways.Abbreviations B.c. brachium conjunctivum - CeM nucleus centralis medialis thalami - CL nucleus centralis lateralis thalami - CM nucleus centrum medianum - D nucleus vestibularis descendons - f cell group f - g cell group g - GLD corpus geniculatum laterale dorsalis - GLV corpus geniculatum laterale ventralis - i.e. nucleus intercalatus - L nucleus vestibularis lateralis - LD nucleus lateralis dorsalis thalami - LIM lamina medullaris interna - Lim nucleus limitans - LP nucleus lateralis posterior thalami - M nucleus vestibularis medialis - MD nucleus medialis dorsalis thalami - MGmc corpus geniculatum mediale, pars magnocellularis - MGp corpus geniculatum mediale, pars principalis - N.cu.e. nucleus cuneatus externus - N.f.c. nucleus fasciculi cuneati - N.mes. V nucleus mesencephalicus nervi trigemini - NR nucleus ruber - N.tr.s. nucleus tractus solitarius - N. VII nervus facialis - N. VIII nervus statoacusticus - PC pedunculus cerebri - Pc nucleus paracentralis thalami - Pf nucleus parafascicularis - p.h. nucleus prepositus hypoglossi - PO posterior thalamic group - PO1 lateral part of PO - POm medial part of PO - Prt nucleus pretectalis - Pul pulvinar - R nucleus reticularis thalami - S nucleus vestibularis superior - Sg nucleus suprageniculatus - SN substantia nigra - Sv nucleus supravestibularis - Tr.s. tractus solitarius - VA nucleus ventralis anterior thalami - VL nucleus ventralis lateralis thalami - VPL nucleus ventralis posterior lateralis - VPL1 lateral part of VPL - VPLm medial part of VPL - VPM nucleus ventralis posterior medialis - x cell group x - y cell group y - z cell group z - V nucleus motorius nerve trigemini - X nucleus dorsalis nerve vagi - XII nucleus nervi hypoglossi     

Distribution of serotonin- and dopamine-immunoreactivity in the brain of the teleost Clarias gariepinus

The distribution of serotonergic and dopaminergic cell bodies and varicose fibres in the brain of the teleost Clarias gariepinus was studied immunohistochemically using antisera against formaldehyde-conjugated serotonin and dopamine. Many serotonergic and dopaminergic fibres innervated the areas dorsalis telencephali pars medialis and pars lateralis dorsalis, as well as the area ventralis telencephali pars ventralis. In the diencephalon, a large number of serotonergic and some dopaminergic fibres were found in the preoptic nucleus, innervating the cells of this nucleus. In addition, serotonergic and dopaminergic fibres were observed in the pituitary stalk and in all regions of the pituitary gland. Moreover, the diencephalon contained the highest number of serotonin- or dopamine-immunoreactive cell bodies. These cells were confined to the same periventricular nuclei as the nucleus ventromedialis thalami, the nucleus posterior periventricularis, the nucleus lateralis tuberis, the nuclei recessus lateralis and recessus posterioris. Most cells of these nuclei were in contact with the cerebrospinal fluid of the third ventricle. The brainstem contained serotonergic cell bodies in the raphe nuclei and a few serotonergic and dopaminergic fibres. The torus semicircularis was densely innervated by serotonergic fibres and, to a lesser extent, dopaminergic fibres. In the midbrain of Clarias gariepinus, no dopaminergic homologue of the substantia nigra was observed. The results are discussed both in a comparative and a physiological context. In this regard, special attention has been paid to the contribution of hypothalamic monoamines in the regulation of gonadotropin secretion as an essential step in the neuro-endocrine control of reproduction.     

Do pontocerebellar mossy fibres give off collaterals to the cerebellar nuclei? An experimental study in the cat with implantation of crystalline HRP-WGA

In 15 cats with implantations of crystalline HRP-WGA in the cerebellar nuclei and tetramethylbenzidine histochemistry, the pontine nuclei were carefully examined for presence of retrogradely labelled cells. Findings in the nucleus reticularis tegmenti pontis and the inferior olive, both known to project to the cerebellar nuclei, served as controls for effectiveness of uptake and transport. After implantations restricted to the lateral cerebellar nucleus in 5 cats altogether two labelled cells were found in the contralateral pontine nuclei in regions receiving afferents from the lateral nucleus. In contrast, many labelled cells occurred in the nucleus reticularis tegmenti pontis and the inferior olive. After implantations in 5 cats restricted to the posterior or anterior interposed nuclei, altogether only one labelled cell was found in the pontine nuclei, while many labelled cells occurred in the inferior olive. The nucleus reticularis tegmenti pontis contained a small number of retrogradely labelled cells after implantations in the anterior interposed nucleus, but none after implantations restricted to the posterior interposed nucleus. After implantations restricted to the medial (fastigial) nucleus, no retrogradely labelled cells were found in the pontine nuclei and nucleus reticularis tegmenti pontis (although many were present in the inferior olive). The present findings support earlier conclusions based on anterograde tracing methods that the cerebellar nuclei receive very few, if any, afferents from the pontine nuclei.