猫丘脑中央外侧核的皮质下传入联系

本实验用HRP逆行性轴浆运输技术,对猫丘脑中央外侧核的传入纤维联系及其局部定位关系进行了观察。投射至丘脑中央外侧核尾侧区的主要核团包括:外侧膝状体腹核背侧带、丘脑网状核特别是它的背侧部、上丘深层,以同侧为主。板内核、丘脑下部外侧区和黑质网状部神经元的轴突终止在同侧丘脑中央外侧核吻侧区。丘脑中央外侧核全长的传入起自脑干网状结构和前庭神经核,呈双侧投射。前者以同侧为主,后者以对侧占优势。同侧未定带,顶盖前区、动眼神经核周围的细胞群、对侧三叉神经感觉主核、楔束核、薄束核以及小脑齿状核内也含有少量标记细胞。我们还观察到HRP注射中心区位于中央外侧核并扩散至丘脑腹前核者,同侧脚内核含大量HRP阳性细胞,而Gudden被盖腹侧核内充满密集的标记终末。这些结果表明,丘脑中央外侧核可能涉及多种感觉和运动功能。     

大白鼠丘脑背内侧核的传入纤维联系

用HRP逆行传递法,研究了大白鼠丘脑背内侧核(MD)的传入纤维联系.发现以下核团有细胞发出纤维投射到丘脑背内侧核:额叶皮质、边缘系统(以杏仁核、斜角带和海马为主)、间脑某些核团(主要是丘脑腹侧核、未定带、下丘脑)、中脑(以上丘、脚间核、黑质为主)、脑干网状结构(主要是中脑楔状核)、中缝核群(主要是中缝背核和上中央核)、小脑齿状核和间位核以及蓝斑核。根据丘脑背内侧核的传入纤维联系和有关报道,对该核的整合作用进行了分析。     

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.     

猫上丘至间脑和脑干的若干传出投射——HRP法顺行性研究

本文用顺行性轴浆运输技术,对猫上丘传出投射进行了研究。HRP注射至吻端上丘后,许多标记终末见于同侧外侧膝状体腹核的腹内侧区、未定带腹侧部、丘脑后外侧核内侧份、束旁核和中央正中核。丘脑的背内侧核和网状核内标记终末较少。同侧二叠体旁核尾侧区、桥核背外侧区以及对侧内侧副橄榄核背内侧区有最密集的标记终末。HRP注射至尾端上丘后,仅同侧桥核背外侧区有大量标记终末,二叠体旁核内标记终末较吻端上丘注射者大为减少,上述丘脑各核及内侧副橄榄核内均未观察到标记终末。这些结果表明,上丘至丘脑和脑干一些核团的传出投射,具有一定的局部定位关系。     

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.     

大鼠上丘的传出投射——ARG法和WGA-HRP法研究

本实验将~3H-Leucine 或 WGA-HRP 定位注(导)入大鼠一侧上丘内,观察了上丘传出纤维的终止部位。上丘浅层的传出纤维下行终止于二叠体旁核(以同侧核的背、腹群为主)、同侧桥核的背外侧部;其上行投射终止于内侧膝状体、膝上核、顶盖前区后核、丘脑外侧后核(以上均为两侧性,以同侧为主)、同侧的内及外侧视束核和外侧膝状体的背侧及腹侧核。另外,在两侧视束和视束交叉处均有标记颗粒。上丘中、深层的传出纤维终止于同侧中央灰质、Darkschewitsch 核、Cajal 中介核、楔形核以及对侧上丘;上行终止于内测膝状体,膝上核、顶盖前区前核、丘脑外侧后核(以上均为两侧性,以同侧为主)、束旁核、未定带、丘脑腹侧核(以上均为同侧);下行终止于同侧的有二叠体旁区和二叠体旁核,桥核的背外侧部、下丘外侧部、桥脑和延髓网状结构、下橄榄核的外侧部;终止于对侧的有二叠体旁核、桥脑和延髓网状结构内侧部、下橄榄核的内侧副核、脊髓颈段前角。     

豚鼠脑桥被盖部位HRP逆行标记的传入联系

本研究应用HRP微电泳技术,将HRP注射至豚鼠脑桥的腹侧被盖和背侧被盖,追踪其逆行传入投射。将HRP注射至脑桥腹侧被盖后,中脑上丘腹侧的中脑水管周围灰质和网状结构交界处(MSR),具有较密集的标记神经元。此外,在下丘腹侧的楔状核(MLR)、三叉神经脊束核、延髓网状巨细胞核、前庭内和外侧核、蓝斑及其腹侧的网状结构部分以及脊髓颈膨大灰质,也观察到了标记细胞。将HRP注射至脑桥背侧被盖后,脑桥尾侧网状核和延髓巨细胞网状核的标记神经元较多,前庭内、外侧核和外侧楔束核也见到标记细胞,中脑部位仅在红核及其附近见到少量标记细胞。蓝斑及其腹侧的网状结构部分和脊髓灰质未见标记细胞。     

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。     

大鼠面神经核的纤维联系-HRP逆行追踪研究

向大鼠一侧面神经核导入HRP,结果表明:延髓和脑桥同侧的Kolliker-Fuse核、三叉神经核、结合臂旁核和双侧的前庭内侧核、延髓中央网状核,中脑对侧的外侧丘系腹侧核、红核、上丘和双侧Cajal氏间位核均有向面神经核的直接投射。并在同侧下丘脑室旁核、未定带和底丘脑核发现逆行标记细胞。     

大白鼠伏核的神经联系—HRP、WGA-HRP、荧光法研究

用HRP和荧光素—伊凡氏兰(EB)、核黄(NY)对大白鼠伏核的传入性联系,用WGAHRP对其传出性联系进行了实验研究。单纯HRP(19例)和荧光素EB(6例)、NY(4例)注入或泳入伏核后所产生的逆行标记结果基本一致。在丘脑,标记细胞大量出现于丘脑的带旁核、室周核、丘脑内侧核、板内核群;其它如连合核、菱形核和丘脑后内侧核也见到一些标记细胞。在中脑、黑质密带内侧份、被盖腹侧区有大量标记细胞。在边缘系统的海马、杏仁体有大量标记细胞,而内嗅区皮质和下脚仅在一些例中有明显的标记细胞。外例隔核、苍白球、尾壳核和丘脑下部等均未见标记。将WGA-HRP注入伏核内(7例),顺行性标记纤维主要经前脑内侧束下行。标记终支最明显的部位是腹侧苍白球、终纹床核和黑质网状带;其他如外侧隔核、下丘脑外侧核、丘脑底核和Forel H_2区、未定带、黑质密带等处也可见到少量的标记终支。     

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.     

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     

Difference in projections to the lateral and medial facial nucleus: anatomically separate pathways for rhythmical vibrissa movement in rats

Summary The present paper demonstrates that the lateral and medial subdivisions of the rat facial motor nucleus (NVII) receive differing mesencephalic and metencephalic projections. In order to study brain projections to facial nucleus, horseradish peroxidase (HRP) was injected iontophoretically into the entire facial nucleus or the following subdivisions: lateral, dorsolateral, medial, intermediate, and ventral. In the mesencephalic region, the retrorubral nucleus was found to project to the contralateral medial subdivision of NVII, while the red nucleus was found to project to the contralateral lateral subdivision of NVII. Other mesencephalic projections to the facial nucleus arose from the deep mesencephalic nucleus, oculomotor nucleus, central gray including inter stitial nucleus of Cajal and nucleus Darkschewitsch, superior colliculus and substantia nigra (reticular). In the metencephalic region, the Kölliker-Fuse nucleus, parabrachial nucleus, and the ventral nucleus of the lateral lemniscus projected mainly to the ipsilateral lateral subdivision of NVII. In addition, the trapezoid, pontine reticular, vestibular, and motor trigeminal nuclei were observed to have predominantly ipsilateral connections to the facial nucleus. In contrast, projections from the myelencephalic region were to both the lateral and medial subdivision of NVII. The medullary reticular nucleus, ambiguus nucleus, spinal trigeminal nucleus and parvocellular reticular nucleus projected to both lateral and medial subdivisions of NVII with an ipsilateral predominance. The gigantocellular and paragigantocellular reticular nuclei, raphe magnus, external cuneate nucleus and the nucleus of the solitary tract also projected to the facial motor nucleus. Surprisingly, no direct projections to the NVII were observed from diencephalic and telencephalic regions. Our findings that the lateral subdivision of NVII which innervates vibrissa-pad-muscles (Dom et al. 1973; Martin and Lodge 1977; Watson et al. 1982) receives different metencephalic and mesencephalic projections than medial subdivision which controls pinna movement (Henkel and Edwards 1978), suggest that the functional difference between these subdivisions is mediated by the anatomically separate pathways. We confirmed our anatomical findings by eliciting exclusively vibrissa responses by electrical stimulation of the nuclei which project to the lateral subdivision of NVII.     

The afferent connections of the inferior olivary complex in rats: A study using the retrograde transport of horseradish peroxidase

Retrograde transport of horseradish peroxidase (HRP) was used to define the origin of afferents to the inferior olivary complex (IOC) in rats. Using both ventral and dorsal surgical approaches to the brainstem, HRP was injected into the IOC through a micropipette affixed to the tip of a 1-μl Hamilton syringe. After a 2-day postoperative survival, animals were sacrificed by transcardiac perfusion with a 1% paraformaldehyde-1.25% gluteraldehyde solution, and brains were processed according to the DeOlmos protocol (1977), using o-dianisidine as the chromogen. Labeled cells were found at many levels of the nervous system extending from lumbar spinal cord to cerebral cortex. This wide-ranging input from numerous regions clearly underscores the complexity of the IOC and its apparent involvement in several functions. Within the spinal cord, labeled neurons were identified from cervical to lumbar but not at sacral levels. These neurons were found contralaterally in the neck region of the dorsal horn and in the medial portions of the intermediate gray. In the caudal brainstem, reactive cells in the dorsal column nuclei, the spinal trigeminal nucleus, and the subnucleus y of the vestibular complex were observed primarily contralateral to the injection sites. Labeling within the gigantocellular, magnocellular, ventral, and lateral reticular nuclei and the nucleus prepositus hypoglossi was primarily ipsilateral. Reactive neurons in the medial and inferior vestibular nuclei were predominantly ipsilateral or contralateral to HRP injections into the caudal or rostral IOC, respectively. The dentate and interposed nuclei of the cerebellum contained small, lightly labeled neurons primarily contralateral to the injection site, while the fastigial nuclei contained a few relatively large, heavily labeled cells bilateral to caudal olivary injections. Ipsilaterally labeled mesencephalic regions included the periaqueductal gray, interstitial nucleus of Cajal, rostromedial red nucleus, ventral tegmental area, medial terminal nucleus of the accessory optic tract, nucleus of the optic tract, and the lateral deep mesencephalic nucleus. The caudal part of the pretectum and small cells of the stratum profundum of the superior colliculus were labeled predominantly contralateral to the injection. In the caudal diencephalon labeled neurons were most numerous within the nucleus of Darkschewitsch and the subparafascicular nucleus, primarily ipsilateral to olivary injections. Scattered reactive neurons were also found within the ipsilateral zone incerta. With the exception of the zona incerta, all labeled mesencephalic and diencephalic nuclei had some bilateral representation of labeled cells. No labeled neurons were identified within the basal ganglia, while numerous reactive cells were found bilaterally within layer V of the frontal and parietal cerebral cortex.     

Projections from the superior colliculus to a region of the central mesencephalic reticular formation (cMRF) associated with horizontal saccadic eye movements

Summary Radioactive wheatgerm agglutinin (WGA) and horseradish peroxidase (HRP) were injected into portions of the mesencephalic reticular formation at sites where electrical stimulation induced either small or large contralateral horizontal saccadic eye movements. We have designated this region as the Central MRF (cMRF). It contains both cells and fiber tracts, including the efferent output of the superior colliculus (SC), destined for the dorsal tegmental decussation and the predorsal bundle. Cells labelled by WGA and HRP injections were found in the intermediate and deep layers of the superior colliculus and the adjacent central gray matter on the ipsilateral side. Injections into the dorsal cMRF, at sites where small saccades were induced, caused labelling of cells in the rostral intermediate layer of SC. Injections into the ventral cMRF, at points where large saccades were elicited, caused labelling of cells in the caudal intermediate layer of SC. The deepest layers of SC and the adjacent central gray were also labelled from the small eye movement region of dorsal cMRF. We interpret these findings to indicate that the intermediate layers of SC send axonal projections to the horizontal eye movement region of the MRF in a topographic fashion. The projection from the intermediate layer is organized so that regions in SC and cMRF related to small or to large eye movements are interconnected. The results support the hypothesis that cMRF is a topographically organized area, involved, like SC, in the control of eye movements. Since both cMRF and the superior colliculus project to areas of the pons and medulla where saccadic eye movements are produced, they could give rise to parallel pathways for the generation of contralateral saccades.Abbreviations III oculomotor nucleus - IV trochlear nucleus - ap area pretectalis - BC brachium conjunctivum - BSC brachium of the superior colliculus - cg central gray - cMRF central MRF - d deep layer of SC - DAB diaminobenzidine - EOG electro-oculography - h habenula nuclei - HRP horseradish peroxidase - iC interstitial nucleus of Cajal - ic inferior colliculus - li nucleus limitans - mg medial geniculate body - MLF medial longitudinal fasciculus - nIII oculomotor nerve - nIV trochlear nerve - on olivary nucleus - p pulvinar - PC posterior commissure - riMLF rostral interstitial nucleus of the MLF - rn red nucleus, pars magnocellularis - rnp red nucleus, pars parvocellularis - s superficial layer of SC - SC superior colliculus - sl sublentiform nucleus - sn substantia nigra - TMB tetramethyl benzidine - TR tractus retroflexus - WGA wheatgerm agglutinin Supported by NIH Research grant EY 02296, Deutsche Forschungsgemeinschaft grant SFB 200/A3 and Core Center grant EY 01867     

Subcortical afferent and efferent connections of the superior colliculus in the rat and comparisons between albino and pigmented strains

Summary Subcortical connections of the superior colliculus were investigated in albino and pigmented rats using retrograde and anterograde tracing with horseradish peroxidase (HRP), following unilateral injection of HRP into the superior colliculus. Afferents project bilaterally from the parabigeminal nuclei, the nucleus of the optic tract, the posterior pretectal region, the dorsal part of the lateral posterior-pulvinar complex and the ventral nucleus of the lateral lemniscus; and ipsilaterally from the substantia nigra pars reticulata, the pars lateralis of the ventral lateral geniculate nucleus, the intergeniculate leaflet, the zona incerta, the olivary pretectal nucleus, the nucleus of the posterior commissure, the lateral thalamus, Forel's field H₂, and the ventromedial hypothalamus. Collicular efferents terminate ipsilaterally in the anterior, posterior and olivary pretectal nuclei, the nuclei of the optic tract and posterior commissure, the ventrolateral part of the dorsal lateral geniculate nucleus, the pars lateralis of the ventral lateral geniculate nucleus, the intergeniculate leaflet, and the zona incerta; and bilaterally in the parabigeminal nuclei and lateral posterior-pulvinar complex (chiefly its dorsal part). The general topographical patterns of some of the afferent and efferent projections were also determined: the caudal and rostral parts of the parabigeminal nucleus project to the caudal and rostral regions, respectively, of the superior colliculus; caudal superior colliculus projects to the most lateral, and lateral superior colliculus to the most caudal part of the terminal field in the dorsal lateral geniculate nucleus; caudolateral superior colliculus projects to the caudal ventrolateral part of the ventral lateral geniculate nucleus, while rostromedial parts of the colliculus project more rostrally and dorsomedially. Following comparable injections in pigmented and albino animals, fewer retrogradely labelled cells were found in subcortical structures in the albino than in the pigmented rats. The difference was most marked in nuclei contralateral to the injected colliculus. Thus, the effects of albinism on the nervous system may be more widespread than previously thought.M. R. C. Scholar     

Supramedullary projections to the dorsal and ventral divisions of the paramedian reticular nucleus in the cat

Summary Injections of combined lectin-conjugated and unconjugated horseradish peroxidase were made in the dorsal (d) and ventral (v) divisions of the paramedian reticular nucleus (PRN), a precerebellar relay nucleus, of the cat. The origins of supramedullary afferent projections to the PRN were identified in the pons, midbrain and cerebral cortex using the transverse plane of section. The data indicate a segregation of input from a number of sites to the dPRN and vPRN. The interstitial nucleus of Cajal projects bilaterally to the dPRN and predominantly to the ipsilateral side. The vPRN receives only a unilateral projection from the ipsilateral nucleus of Cajal. Major afferent projections to the vPRN arise from the ipsilateral nucleus of Darkschewitsch and the intermediate layer of the contralateral superior colliculus. Neither of these sites projected to the dPRN. The raphe nuclei and medial reticular formation of the pons and midbrain contribute a moderate input to both divisions of the PRN. A moderate bilateral cerebral cortical projection arises from the first somatomotor area (SMI). The ventral coronal and anterior sigmoid gyri project mainly to the dPRN and vPRN respectively. Smaller afferent projections arise from the posterior sigmoid gyri and area 6 of Hassler and Mühs-Clement (1964) in the medial wall of the anterior sigmoid gyrus. Inputs from the accessory oculomotor nuclei, tectal regions and the first somatomotor cortex suggest a role in postural control for the PRN which may underlie its involvement in mediating orthostatic reflexes.Abbreviations 3N oculomotor nerve - 5ME mesencephalic nucleus (trigeminal) - 5MN motor nucleus (trigeminal) - 5PN sensory nucleus, parvocellular division (trigeminal) - 5SM sensory nucleus, magnocellular division (trigeminal) - 12M hypoglossal nucleus - 12N hypoglossal nerve - AQ aqueduct - BC brachium conjunctivum - BP brachium pontis - CAE nucleus caeruleus - Cl inferior central nucleus (raphe) - CM centromedian nucleus - CNF cuneiform nucleus - CS superior central nucleus (raphe) - D nucleus of Darkschewitsch - DRM dorsal nucleus of the raphe (median division) - EW Edinger-Westphal nucleus - FTC central tegmental field - FTG gigantocellular tegmental field - FTP paralemniscal tegmental field - ICA interstitial nucleus of Cajal - ICC inferior colliculus (central nucleus) - INC nucleus incertus - INT nucleus intercalatus - ION inferior olivary nucleus - LLV ventral nucleus of lateral lemniscus - LP lateral posterior complex of thalamus - MGN medial geniculate nucleus - MLF medial longitudinal fasciculus - TN nucleus of optic tract - P pyramidal tract - PCN nucleus of posterior commissure - PF parafascicular nucleus - PH nucleus praepositus hypogloss - PRN paramedian reticular nucleus (a — accessory division; d — dorsal division; v — ventral division) - PUL pulvinar - SCD superior colliculus (deep layer) - SNC substantia nigra (compact division) - SON superior olivary nucleus - RM red nucleus (magnocellular) - RR retrorubral nucleus - TB trapezoid body - TDP dorsal tegmental nucleus (pericentral division) - TRC tegmental reticular nucleus (central division) - TV ventral tegmental nucleus - V3 third ventricle - V4 fourth ventricle - VB ventrobasal complex of thalamus - VIN inferior vestibular nucleus - VSN superior vestibular nucleus - ZI zona incerta Supported by the Medical Research Council of Canada