Somatosensory systems and the milk-ejection reflex in the rat. II. The effects of lesions in the ventroposterior thalamic complex, dorsal columns and lateral cervical nucleus-dorsolateral funiculus

Bilateral electrolytic lesions of some somatosensory structures in the thalamus and spinal cord were made in order to assess their participation in the afferent limb of the milk-ejection reflex in the rat. Lesions involving the lateral cervical nucleus and a part of the dorsolateral funiculus region blocked the milk-ejection reflex, whereas animals with lesions in the dorsal column of the spinal cord or in the ventroposterior complex of the thalamus displayed milk-ejection reflexes similar to those of control animals. Unilateral injections of horseradish peroxidase coupled to wheat germ agglutinin were made after lesioning the lateral cervical nucleus and part of the dorsolateral funiculus. Anterograde labelling was seen mainly contralateral to the injection site: in the external nucleus of the inferior colliculus, the intercollicular zone, the brachium of the inferior colliculus, the lateral reticular nucleus of the thalamus and in the thalamic ventroposterior complex. Sparse projections ipsilateral to the injection site were also observed. These results, combined with our previous observations, suggest that the projection of the lateral cervical nucleus on the mesencephalon is part of the pathway which conveys the sensory information from the suckling stimulus.     

The central cervical nucleus in the cat. II

Summary After HRP injections in kittens and adult cats into parts of the cerebellum known to receive spinal afferents, retrogradely labelled neurones were found in the C1–C4 segments of the spinal cord, primarily in the central cervical nucleus (CCN). A few labelled neurones were also found in laminae IV and VI–IX of Rexed. The results obtained in kittens and adult cats were similar.Control HRP injections were made into the vestibular nuclei and the inferior colliculus. After injections mainly involving the vestibular nuclei a few faintly labelled neurones were found in the C1–C4 segments in, and occasionally also outside the CCN, in laminae VI–VIII. After injections into the inferior colliculus, however, no labelled neurones were observed in these segments.After spinal cord hemisections at C1 and bilateral HRP injections into the anterior lobe, nearly all labelled CCN neurones were found ipsilateral to the hemisections. Labelled axons of such CCN neurones could be traced across the midline to the lateral funiculus. A few neurones were found outside the CCN in laminae VII–IX. Contralaterally labelled neurones were found mainly in lamina VI.Abbreviations b.c. brachium conjunctivum - CN cuneate nucleus - Cr. I, II crus I and II - DV descending (inferior) vestibular nucleus - ECN external cuneate nucleus - i.c.p. inferior cerebellar peduncle (restiform body) - LV lateral vestibular nucleus - MV medial vestibular nucleus - N.d. dentate (lateral) nucleus - N.f. fastigal (medial) nucleus - N.i. interpositus nucleus - N.pr.V principal nucleus of trigeminal nerve - N.V motor nucleus of trigeminal nerve - Ol.s. superior olive - pfl. paraflocculus - pfl.d. dorsal paraflocculus - pmd. paramedian lobule - SC superior colliculus - s.c.p. superior cerebellar peduncle - SV superior vestibular nucleus - Tr.V spinal trigeminal tract - x group x of Brodal and Pompeiano (1957) - I-X cerebellar lobules of Larsell (1953) - I-IX spinal cord laminae (Rexed, 1952)     

Afferent and efferent connections of the ventrolateral tegmental area in the rat

 The present study examined the organization of afferent and efferent connections of the rat ventrolateral tegmental area (VLTg) by employing the retrograde and anterograde axonal transport of Fluorogold and Phaseolus vulgaris-leucoagglutinin, respectively. Our interest was focused on whether the anatomical connections of the VLTg would provide evidence as to the involvement of this reticular area in audiomotor behavior. Our retrograde experiments revealed that minor inputs to the VLTg arise in various telencephalic structures, including the cerebral cortex. Stronger projections originate in the lateral preoptic area, the zona incerta, the nucleus of the posterior commissure and some other thalamic areas, the lateral substantia nigra, the deep layers of the superior colliculus, the dorsal and lateral central gray, the deep mesencephalic nucleus, the paralemniscal zone, the intercollicular nucleus, the external cortex of the inferior colliculus, the oral and caudal pontine reticular nucleus, the deep cerebellar nuclei, the gigantocellular and lateral paragigantocellular reticular nuclei, the prepositus hypoglossal nucleus, the spinal trigeminal nuclei, and the intermediate layers of the spinal cord. Most importantly, we disclosed strong auditory afferents arising in the dorsal and ventral cochlear nuclei and in the cochlear root nucleus. The efferent projections of the VLTg were found to be less widespread. Telencephalic structures do not receive any input from the VLTg. Moderate projections were seen to diencephalic reticular areas, the zona incerta, the nucleus of the posterior commissure, and to various other thalamic areas. The major VLTg projections terminate in the deep layers of the superior colliculus, the deep mesencephalic nucleus, the intercollicular nucleus and external cortex of the inferior colliculus, the oral and caudal pontine reticular nucleus, the gigantocellular and lateral paragigantocellular reticular nuclei, and in the medial column of the facial nucleus. From our data, we conclude that the VLTg might play a role in sensorimotor behavior. Accepted: 3 April 1997     

大白鼠皮质下非听性结构向下丘的投射——WGA-HRP法研究

本实验向大白鼠下丘内注入WGA-HRP,在间脑和脑干内,逆行标记细胞出现于下列非听性区域:双侧(对侧为主)的后索核、三叉神经脊束核、延髓中央核的背侧部;双侧(同侧为主)的蓝斑、桥首网状核、背外侧被盖核、黑质、束旁下核、穹窿周核;双侧臂旁内侧核、中脑被盖深核、丘脑下部外侧区;同侧的上丘深层、未定带;对侧孤束核;以及延髓后中隔、中央被盖核、背中缝核。来自后索核、三叉神经脊束核和孤束核的起源细胞主要位于闩以下平面。结果表明下丘不是单一听觉传导路的中继核,而是一个与多种功能有关的复合体。     

Labelling of cells in the medulla oblongata and the spinal cord of the monkey after injections of horseradish peroxidase in the thalamus

Injections of horseradish peroxidase were performed in macaque monkeys in the intralaminar and the ventroposterior thalamic region, respectively. Following injection in the intralaminar region labelled cells were present in the marginal zone both in the spinal trigeminal nuclues and in the spinal dorsal horn. The same areas contained labelled cells after injections in the ventroposterior thalamic region, but in such experiments labelled cells were also present in the lamina IV–V region of the spinal cord, in the gracile and main cuneate nuclei and in the external cuneate nucleus. Thus, the marginal zone of the spinal cord appears to project to at least two of the thalamic regions receiving spinothalamic fibres in the monkey.     

An anatomical study of the projections from the dorsal column nuclei to the midbrain in cat

Summary The termination of the fibers from the dorsal column nuclei (DCN) to the midbrain has been investigated in the cat with the degeneration method, the anterograde horseradish peroxidase (HRP) method and autoradiography after ³H-leucine injections. The results show that the DCN project to several midbrain regions. The external nucleus of the inferior colliculus (IX) receives the heaviest projection from both the gracile and cuneate nuclei. The DCN fibers form three joint terminal zones in IX. Each terminal zone contains clusters with dense aggregations of DCN fibers. Fairly dense terminal networks are found in the posterior pretectal nucleus (PP) and the compact part of the anterior pretectal nucleus (PAc) as well. More scattered DCN fibers are present in the cuneiform nucleus (CF), the lateral part of the periaqueductal gray (PAG1), the red nucleus (NR), the nucleus of the brachium of the inferior colliculus (B), the mesencephalic reticular formation (MRF) and the intermediate and deep layers of the superior colliculus (SI, SP). The projections to all regions are mainly contralateral. Most of the few ipsilateral fibers terminate in IX.A somatotopic organization was seen in IX and NR. The gracile fibers terminate preferentially in the caudal and lateral part of IX and the cuneate ones preferentially in its rostral and medial part. In the red nucleus the gracile fibers terminate ventral to the cuneate ones. In the pretectal region there was a predominance for gracile fibers. There also appeared to be quantitative differences in the projections from various levels of the gracile nucleus, with more midbrain projecting fibers originating in the rostral than in the middle and caudal parts of the nucleus.     

延髓感觉核向丘脑和下丘的投射——荧光素双标记法

本文应用荧光素双标记法研究了后索核、孤束核、三叉神经脊束核向下丘和丘脑投射神经元的分布及其分支投射。作者将Propidium Iodide注入大白鼠右侧丘脑,Bisbenzimide注入右侧下丘,结果如下:楔束核内被标记的神经元中有88.2％向丘脑投射,它们位于核的主部;11.2％向下丘投射,它们在尾侧主要位于核的边缘部,向吻侧(至闩平面)主要位于核的背外侧端。薄束核内被标记的神经元中向下丘投射者(10.9％)与向丘脑投射者(86.7％)混杂在一起。在此两核内仅有极少量分支投射的双标神经元。孤束核和三叉神经脊束核内被标记的神经元中约有2/3投向丘脑,1/3投向下丘,未见分支投射的双标神经元。     

The cells of origin of the incertofugal projections to the tectum,thalamus, tegmentum and spinal cord in the rat: A study using the autoradiographic and horseradish peroxidase methods

Efferent projections of the zona incerta were examined in the rat using the autoradiographic and horseradish peroxidase methods, with special reference to the cytoarchitectonic structure of the zona incerta.Autoradiographic experiments showed that the incertofugal fiber systems reach ipsilaterally to the thalamus (lateral dorsal, central lateral, ventral lateral geniculate, parafascicular, subparafascicular and reuniens nuclei, and posterior nuclear complex), to the hypothalamus (dorsal, lateral and posterior hypothalamic areas), to the tectum (medial pretectal area, deep pretectal and pretectal nuclei, superior colliculus and periaqueductal gray) and to the midbrain tegmentum, pons and medulla oblongata (subcuneiform, cuneiform and red nuclei, nuclei of the posterior commissure and Darkschewitsch, interstitial nucleus of Cajal, pedunculopontine tegmental nucleus, oral and caudal pontine reticular nuclei, nucleus raphe magnus, gigantocellular reticular nucleus, pontine gray and inferior olivary complex). Contralaterally, incertal efferent fibers reach to the zona incerta.Cells of origin of the incertofugal fiber systems to the tectum, thalamus, tegmentum and spinal cord were examined using the retrograde horseradish peroxidase method. Cells of origin of the incertotectal pathway are located mainly in the ventral and caudal parts of the zona incerta and partly in the antero-polar, dorsal and postero-polar parts. Cells projecting to the thalamus (at least to the lateral dorsal and central lateral nuclei) are situated in the ventral and caudal parts of the zona incerta, but they are rare in the other incertal structures. Cells of origin of the incertotegmental system are located mainly in the dorsal, magnocellular and caudal parts and partly in the antero- and postero-polar parts, but they are not situated in the ventral part. Cells of the magnocellular part project more caudally to the medulla oblongata and spinal cord than those of the other parts of the zona incerta. Forel's field contains many cells projecting to the tegmentum.The results provide good evidence that the cells of origin of efferent projections are topographically organized and are related to cytoarchitectonic areas within the zona incerta.     

Cortical and brain stem projections to the spinal cord of the hedgehog (Erinaceus europaeus). A horseradish peroxidase study

Summary Cortical and brain stem neurons projecting to the spinal cord in the hedgehog were studied by means of the horseradish peroxidase (HRP) tracing method. HRP injections were placed in the first cervical segments, in the cervical enlargement (C₅-T₃) and in the lumbar enlargement. Following injections in the first cervical segments and in the cervical enlargement labelled neurons were observed in the somatic motor and somatic sensory cortices, the paraventricular and the dorsomedial hypothalamic nucleus, the lateral hypothalamic area, the nuclei of field H of Forel, the red nucleus, the mesencephalic reticular formation, the deep layers of the superior colliculus, the Edinger-Westphal nucleus, the periaqueductal grey, the mesencephalic trigeminal nucleus, the loci coeruleus and subcoeruleus, the nuclei raphe dorsalis, centralis superior, raphe magnus, raphe pallidus, and raphe obscurus, the rhombencephalic reticular formation, the lateral, medial and caudal vestibular nuclei, the nucleus ambiguus, the nucleus of the solitary tract and the gracile nucleus. After HRP injections in the lumbar enlargement, labelled neurons were not found in the cortex, the dorsomedial hypothalamic nucleus, the nuclei of field H of Forel, the superior colliculus and the mesencephalic trigeminal nucleus. These results show that cortical and brain stem projection to the spinal cord are comparable to those described in other species.Abbreviations ac anterior commissure - Am nucleus ambiguus - Aq cerebral aqueduct - cc corpus callosum - Cd caudate nucleus - CE cervical enlargement - CeS nucleus centralis superior - CG periaqueductal grey - ci capsula interna - Cq cochlear nuclei - cp cerebral peduncle - Cu cuneiform nucleus - CV caudal vestibular nucleus - DM dorsomedial hypothalamic nucleus - DX dorsal motor nucleus of vagus - EC external cuneate nucleus - EW Edinger-Westphal nucleus - F nuclei of field H of Forel - G gracile nucleus - H nippocampus - IC inferior colliculus - IP interpeduncular nucleus - LC locus coeruleus - LE lumbar enlargement - LH lateral hypothalamic area - LL nucleus of lateral lemniscus - lo lateral olfactory tract - LV lateral vestibular nucleus - MC medial cuneate nucleus - MesV mesencephalic trigeminal nucleus - MG medial geniculate nucleus - MM medial mammillary nucleus - MV medial vestibular nucleus - oc optic chiasm - PH nucleus praepositus - Pn pontine nuclei - Put putamen - PV paraventricular hypothalamic nucleus - R red nucleus - Rd nucleus raphe dorsalis - RGc gigantocellular reticular nucleus - Rl lateral reticular nucleus - Rm nucleus raphe magnus - Rmes mesencephalic reticular formation - Ro nucleus raphe obscurus - Rpa nucleus raphe pallidus - Rpc caudal reticular nucleus of the pons - Rpo rostral reticular nucleus of the pons - Rv ventral reticular nucleus - s solitary tract - SC superior colliculus - SN substantia nigra - SO supraoptic nucleus - SR sulcus rhinalis - STh subthalamic nucleus - siV spinal tract of trigeminal nerve - STV nucleus of spinal tract of trigeminal nerve - subC locus subcoeruleus - SuM supramammillary nucleus - Th thalamus - TS nucleus of solitary tract - VM ventromedial hypothalamic nucleus - ZI zona incerta - 3V third ventricle - 4V fourth ventricle - IV layer IV of the cortex - V layer V of the cortex - VI layer VI of the cortex - 7 facial nucleus - 12 hypoglossal nucleus     

An autoradiographic analysis of ascending projections from the medullary reticular formation in the rat

Ascending projections from the several nuclei of the medullary reticular formation were examined using the autoradiographic method. The majority of fibers labeled after injections of [3H]leucine into nucleus gigantocellularis ascended within Forel's tractus fasciculorum tegmenti which is located ventrolateral to the medial longitudinal fasciculus. Nucleus gigantocellularis injections produced heavy labeling in the pontomesencephalic reticular formation, the intermediate layers of the superior colliculus, the pontine and midbrain central gray, the anterior pretectal nucleus, the ventral midbrain tegmentum including the retrorubral area, the centromedian-parafascicular complex, the fields of Forel/zona incerta, the rostral intralaminar nuclei and the lateral hypothalamic area. Nucleus gigantocellularis projections to the rostral forebrain were sparse. Labeled fibers from nucleus reticularis ventralis, like those from nucleus gigantocellularis, ascended largely in the tracts of Forel and distributed to the pontomedullary reticular core, the facial and trigeminal motor nuclei, the pontine nuclei and the dorsolateral pontine tegmentum including the locus coeruleus and the parabrachial complex. Although projections from nucleus reticularis ventralis diminished significantly rostral to the pons, labeling was still demonstrable in several mesodiencephalic nuclei including the cuneiform-pedunculopontine area, the mesencephalic gray, the superior colliculus, the anterior pretectal nucleus, the zona incerta and the paraventricular and intralaminar thalamic nuclei. The main bundle of fibers labeled by nucleus gigantocellularis-pars alpha injections ascended ventromedially through the brainstem, just dorsal to the pyramidal tracts, and joined Forel's tegmental tract in the midbrain. With the brainstem, labeled fibers distributed to the pontomedullary reticular formation, the locus coeruleus, the raphe pontis, the pontine nuclei, and the dorsolateral tegmental nucleus and adjacent regions of the pontine gray. At mesodiencephalic levels, labeling was present in the rostral raphe nuclei (dorsal, median and linearis), the mesencephalic gray, the deep and intermediate layers of the superior colliculus, the medial and anterior pretectal nuclei, the ventral tegmental area, zona incerta as well as the mediodorsal and reticular nuclei of the thalamus. Injections of the parvocellular reticular nucleus labeled axons which coursed through the lateral medullary tegmentum to heavily innervate lateral regions of the medullary and caudal pontine reticular formation, cranial motor nuclei (hypoglossal, facial and trigeminal) and the parabrachial complex.(ABSTRACT TRUNCATED AT 400 WORDS)     

A quantitative study of the projections of the gracile, cuneate and trigeminal nuclei and of the medullary reticular formation to the thalamus in the rat

Following injection of horseradish peroxidase into the thalamus of one side, the numbers of labelled neurons in the nuclei of the dorsal funiculi and in the trigeminal sensory complex were counted. A comparative study was made of the pattern of labelling after a range of survival times, and animals surviving for 72 h after injection were used to provide detailed quantitative information about the patterns of distribution of labelled cells. The principal sensory nucleus of the trigeminal nerve (8683 labelled neurons) and the nucleus of the spinal trigeminal tract, pars interpolaris (1920) label heavily after thalamic injection. Pars oralis of the spinal nucleus labels more sparsely (524 labelled neurons), while the pars caudalis (260 labelled neurons) shows a laminar labelling pattern which continues across the spinomedullary junction into the upper cervical segments. The gracile (2152 labelled neurons) and cuneate (2339) nuclei also show rostrocaudal variation in labelling density: the middle one-third of each nucleus contains 66% of labelled gracile and cuneate cells. The findings are correlated with known features of the arrangement of the ascending sensory projections from these nuclei in various species, and are compared with previous findings on the distribution of thalamically-projecting cells in the upper cervical segments of the spinal cord.     

长翼蝠(Miniopterus Schrebersi)上丘与传递超声信息有关核团的传入联系—HRP法

用HRP逆行追踪法结合电生理学技术,对21只长翼蝠上丘(SC)超声信息的传入联系进行了形态学研究。13只动物上丘的听应部位电泳HRP后,标记神经元恒定地出现于双侧的下丘(IC,同侧为主)和外侧丘系背核(DNLL,对侧占优势)。约半数动物的同侧前外侧橄榄周核(ALPO)存在标记神经元。此外,标记神经元还出现于下列结构中,同侧的舌下神经前置核(n.Ⅻ)、小脑顶核(F)、黑质(SN)、后连合核(NPC)、丘脑(THa)、未定带(ZI),对侧的小脑齿状核(D)、双侧的中脑网状结构(MRF)、上丘(SC)。8只长翼蝠上丘的非听反应部位电泳HRP后,同侧的舌下神经前置核、小脑顶核、黑质、后连合核、丘脑、未定带,对侧的小脑齿状核,双侧的中脑网状结构及上丘亦见标记神经元。本实验提示:上丘的超声信息主要是经过同侧前外側橄榄周核和下丘以及对侧的外侧丘系背核中继传入的。     

Demonstration of spinocerebellar projections in cat using anterograde transport of WGA-HRP,with some observations on spinomesencephalic and spinothalamic projections

Summary Wheat germ agglutinin-horseradish peroxidase (WGA-HRP) conjugate was injected into the lumbar or cervical spinal cord of adult cats in order to examine its usefulness as an anterograde tracer of long ascending spinal tracts. Heavily labeled fibers and terminal-like structures were found in restricted regions of the granular layer of the cerebellar cortex in all animals. The terminal-like structures showed features characteristic of mossy fiber rosettes. Many labeled terminals were found in regions anatomically and physiologically defined as cerebellar hind limb regions after lumbar cord injections. Relatively few labeled terminals were found in both hind limb and in forelimb regions after cervical cord injections. Although the cervical spinal cord is known to project to both hind limb and forelimb regions, it cannot be entirely excluded that some of the labeling in the hind limb regions was derived from uptake by fibers of passage.In addition to labeling in the cerebellar cortex, labeled fibers and terminals were also observed in the cerebellar medial and interposed nuclei, regardless of whether the injections had been made into the lumbar or the cervical spinal cord.Several midbrain and thalamic regions were found to contain labeled fibers and terminal-like profiles in all cases. In the midbrain the periaqueductal gray, the nucleus of Darkschewitsch and the posterior pretectal nucleus contained fairly dense labeling. Labeling was more scattered in the cuneiform nucleus, the mesencephalic reticular formation, the superior colliculus and in the magnocellular part of the medial geniculate body. Four major regions in the thalamus, namely the central lateral nucleus, the zona incerta, the medial part of the posterior complex and the submedius nucleus contained labeling of variable density.The present findings show that the WGA-HRP conjugate can be used as a tracer for the study of long fiber tracts within the central nervous system.Supported by the Swedish Medical Research Council, Projects Nos. 553 and 3391     

Projections of the bed nucleus of the stria terminalis to the mesencephalon,pons, and medulla oblongata in the cat

Summary Injections of HRP in the nucleus raphe magnus and adjoining medial reticular formation in the cat resulted in many labeled neurons in the lateral part of the bed nucleus of the stria terminalis (BNST) but not in the medial part of this nucleus. HRP injections in the nucleus raphe pallidus and in the C2 segment of the spinal cord did not result in labeled neurons in the BNST. Injections of ³H-leucine in the BNST resulted in many labeled fibers in the brain stem. Labeled fiber bundles descended by way of the medial forebrain bundle and the central tegmental field to the lateral tegmental field of pons and medulla. Dense BNST projections could be observed to the substantia nigra pars compacta, the ventral tegmental area, the nucleus of the posterior commissure, the PAG (except its dorsolateral part), the cuneiform nucleus, the nucleus raphe dorsalis, the locus coeruleus, the nucleus subcoeruleus, the medial and lateral parabrachial nuclei, the lateral tegmental field of caudal pons and medulla and the nucleus raphe magnus and adjoining medial reticular formation. Furthermore many labeled fibers were present in the solitary nucleus, and in especially the peripheral parts of the dorsal vagal nucleus. Finally some fibers could be traced in the marginal layer of the rostral part of the caudal spinal trigeminal nucleus. These projections appear to be virtually identical to the ones derived from the medial part of the central nucleus of the amygdala (Hopkins and Holstege 1978). The possibility that the BNST and the medial and central amygdaloid nuclei must be considered as one anatomical entity is discussed.Abbreviations AA anterior amygdaloid nucleus - AC anterior commissure - ACN nucleus of the anterior commissure - ACO cortical amygdaloid nucleus - AL lateral amygdaloid nucleus - AM medial amygdaloid nucleus - APN anterior paraventricular thalamic nucleus - AQ cerebral aqueduct - BC brachium conjunctivum - BIC brachium of the inferior colliculus - BL basolateral amygdaloid nucleus - BNSTL lateral part of the bed nucleus of the stria terminalis - BNSTM medial part of the bed nucleus of the stria terminalis - BP brachium pontis - CA central nucleus of the amygdala - Cd caudate nucleus - CI inferior colliculus - CL claustrum - CN cochlear nucleus - CP posterior commissure - CR corpus restiforme - CSN superior central nucleus - CTF central tegmental field - CU cuneate nucleus - D nucleus of Darkschewitsch - EC external cuneate nucleus - F fornix - G gracile nucleus - GP globus pallidus - HL lateral habenular nucleus - IC interstitial nucleus of Cajal - ICA internal capsule - IO inferior olive - IP interpeduncular nucleus - LC locus coeruleus - LGN lateral geniculate nucleus - LP lateral posterior complex - LRN lateral reticular nucleus - MGN medial geniculate nucleus - MLF medial longitudinal fascicle - NAdg dorsal group of nucleus ambiguus - NPC nucleus of the posterior commissure - nV trigeminal nerve - nVII facial nerve - OC optic chiasm - OR optic radiation - OT optic tract - P pyramidal tract - PAG periaqueductal grey - PC cerebral peduncle - PO posterior complex of the thalamus - POA preoptic area - prV principal trigeminal nucleus - PTA pretectal area - Pu putamen - PUL pulvinar nucleus - R red nucleus - RF reticular formation - RM nucleus raphe magnus - RP nucleus raphe pallidus - RST rubrospinal tract - S solitary nucleus - SC suprachiasmatic nucleus - SCN nucleus subcoeruleus - SI substantia innominata - SM stria medullaris - SN substantia nigra - SO superior olive - SOL solitary nucleus - SON supraoptic nucleus - spV spinal trigeminal nucleus - spVcd spinal trigeminal nucleus pars caudalis - ST stria terminalis - TRF retroflex tract - VC vestibular complex - VTA ventral tegmental area of Tsai - III oculomotor nucleus - Vm motor trigeminal nucleus - VI abducens nucleus - VII facial nucleus - Xd dorsal vagal nucleus - XII hypoglossal nucleus     

Subcortical projections to the lateral geniculate body in the rat

Summary The subcortical projections to the lateral geniculate body (LGB) in the rat were studied by means of discrete HRP iontophoretic deposits in the dorsal or the ventral LGB; the labelling was compared to that resulting from HRP deposits in neighboring nuclei.After injecting HRP in the dorsal LGB, labelled cells appeared bilaterally in the ventral LGB, pretectum, superior colliculus, lateral groups of the dorsal raphe nucleus and locus coeruleus. Ipsilaterally, labelled cells were found in the lateral posterior thalamus, nucleus of the posterior commissure and deep mesencephalic reticular nucleus.After injecting HRP into the ventral LGB, labelled cells were observed bilaterally in the pretectum, superior colliculus and dorsal raphe nucleus (lateral groups). Contralateral labelling appeared in the ventral LGB and parabigeminal nucleus. Ipsilateral labelling was found in the zona incerta, lateral posterior thalamus, lateral and medial mesencephalic reticular formation, vestibular and dorsal tegmental nuclei.These findings provide evidence of subcortical projections to the LGB arising in visually-related areas as well as extravisual areas, which might be related to the LGB boutons that survive complete cortical and retinal ablations.     

Distribution of premotor neurons for orbicularis oculi motoneurons in the cat, with particular reference to possible pathways for blink reflex

After injecting horseradish peroxidase into the facial nucleus regions containing orbicularis oculi motoneurons, labeled neuronal cell bodies were found in the lateral medullary reticular formation, pretectal olivary nucleus, sensory trigeminal nuclei, lateral and medial parabrachial nuclei, ventromedial reticular formation medial to the facial nucleus, red nucleus and its surroundings, anterior horn of the upper cervical cord, medullary raphe nuclei, oculomotor nucleus and its surroundings, nuclei of Darkschewitsch, Cajal and Edinger-Westphal, ventral part of the midbrain central gray, pontine tegmentum, lateral vestibular nucleus and deep layers of the superior colliculus.     

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。     

大鼠外侧巨细胞旁网状核的传出纤维联系——HRP法研究

用HRP轴■顺、逆行追踪法观察了大鼠外侧巨细胞旁网状核(PGCL)的传出纤维联系。结果表明:①PGCL经轴■顺行传递,可投射到与痛觉及其调控有关的核团,如脊髓背角、三叉神经脊束核、导水管周围灰质、束旁核、外侧颈核、脑干网状结构核群等;PGCL还投射到与调节内脏活动有关的孤束核、迷走神经背核、导水管周围灰质背份、臂旁核、脊髓侧角等;也向三叉神经运动核、下丘等处发出投射纤维。②腰髓注射HRP后,在PGCL中见有较多的标记细胞,主要分布在锥体束外侧和面神经核腹内侧区域,部分细胞亦见于锥体束内及PGCL靠近软脑膜处。③向下丘和孤束核注入HRP以作往返印证,在PGCL见到标记细胞和纤维。     

Functional linkage between the electrical activity in the vermal cerebellar cortex and saccadic eye movements

Summary In order to identify cells of origin in the spinal cord of non-primary afferents to the dorsal column nuclei (DCN), the retrograde transport of horseradish peroxidase (HRP) has been utilized in adult cats. 10 to 30% HRP was injected bilaterally (0.6 l per side) in the dorsal medulla of nine cats. In most instances the spread of the injected enzyme extended a few millimeters rostrocaudally and infiltrated the DCN as well as other nuclei and fiber tracts. Labelled cells in these cases are numerous in the upper cervical, brachial and lumbosacral cord but are sparse in thoracic segments below T₁. At upper cervical levels (C₁-C₄) HRP-positive neurons are distributed throughout the grey matter but are especially concentrated in the medial part of lamina VI. Cells projecting to the dorsal medulla are mainly localized in lamina IV and, more ventrally, along the medial border of the dorsal horn in the brachial and lumbosacral cord. Labelled cells at these levels are also scattered within lamina I and laminae VI through VIII in cases in which the focus of the injection involved extensive portions of the medulla. From cases in which bilateral HRP injections were preceded by spinal tractotomy, it appears that the axons of at least the majority of labelled cells in lamina IV ascend in the ipsilateral dorsal quadrant of the spinal cord.In another group of adult cats, 0.1 to 0.25 l of 30 to 50% HRP was injected unilaterally in the dorsal medulla at the level of, or rostral to, the obex. With these volumes of exogenous enzyme, an intense reaction product is largely confined within the limits of the DCN. Labelled cells in these cases are found almost exclusively in the medial part of lamina VI at upper cervical levels and, at brachial and lumbosacral levels, throughout lamina IV and medially in lamina V on the side of the cord ipsilateral to the injection.The results are discussed in relation to the organization of the dorsal horn and ascending pathways with special reference to cells of origin of the spinocervical tract.List of Abbreviations CUN cuneate nucleus - D descending nucleus of the vestibular complex - DV dorsal motor nucleus of the vagus - EC external cuneate nucleus - GR gracile nucleus - HYP hypoglossal nucleus - IO inferior olivary complex - LRN lateral reticular nucleus - PM paramedian nucleus - PYR pyramids - SOL solitary tract and nucleus spin - V spinal trigeminal nucleus     

Descending projections from the superior colliculus in rat: a study using orthograde transport of wheatgerm-agglutinin conjugated horseradish peroxidase

Summary Despite extensive behavioural work on the rat superior colliculus, its descending efferent pathways have not been fully characterised with modern anatomical tract-tracing techniques. To investigate these pathways, wheatgerm-agglutinin conjugated with horseradish peroxidase (1%) was injected at various locations within the superior colliculus of hooded rats. Label judged to be transported orthogradely was plotted on coronal sections modified from the atlas of Paxinos and Watson (1982). Two major descending pathways were identified, (i) The bulk of the fibres in the ipsilateral descending pathway leave the superior colliculus ventrolaterally, and course around the lateral margin of the midbrain reticular formation. Caudally, projecting fibres leave the main bundle to innervate the cuneiform nucleus, and parts of the pontomedullary reticular formation. Terminal fields associated with the major bundle of fibres are found in an area medial to the brachium of the inferior colliculus; the parabigeminal nucleus and adjacent tegmentum; the ventrolateral midbrain reticular formation; and the lateral pontine nuclei, (ii) The fibres of the main contralateral descending pathway leave the superior colliculus ventromedially, to cross midline in the dorsal tegmental decussation. They immediately turn caudally to join the predorsal bundle, in which they run the length of the brainstem to reach the cervical spinal cord. Major terminal fields occur in nucleus reticularis tegmenti pontis; the pedunculopontine/ parabrachial area; paramedian pontomedullary reticular formation; and inferior olive. In addition there is lighter labelling in many areas of the pontomedullary reticular formation and in the cervical spinal cord. There was also a much sparser contralateral descending projection that crossed midline in the tectal commissure, and sent terminals to the contralateral cuneiform area and adjoining regions. These results suggest that the distribution of the descending efferent pathways from the superior colliculus in rats is similar to those described in other species. The fact that the two major pathways project to quite different terminal areas, together with previous findings that they have separate cells of origin within the tectum, suggests that they may also be functionally distinct.