Glycine, glycine receptor subunit and glycine transporters in the rat parabrachial and Kölliker-Fuse nuclei

In the present study, we investigated the expression and distribution of key molecules in the parabrachial (PB) and Kölliker-Fuse nuclei (KF) that determine glycinergic signal transduction. By means of immunocytochemistry, we analyzed the amino acid glycine (Gly), the glycine transporters 1 and 2 (GlyT1, GlyT2), and the ligand binding glycine receptor-subunit α1 (GlyRα1). Gly-immunoreactivity (-ir) was mainly found in varicose fibers and presumed terminal boutons; Gly-ir cell bodies were only occasionally seen. Immunoreactivity for GlyT2 was located in axons while GlyT1-staining was diffuse in the neuropil. Immunolabeling for GlyRα1 occurred mostly as granular staining diffusely distributed throughout the neuropil. Only in the superior lateral PB, the lateral crescent of the PB, and caudally in the KF did GlyRα1-ir outline cell bodies and primary and higher-order dendrites. Furthermore, our data demonstrate a distinct codistribution of immunoreactivities for Gly, GlyT2, and GlyRα1 in a specific set of PB nuclei and in the KF. Strong staining was consistently seen in the internal lateral PB, the ventral lateral PB, the lateral crescent, the medial PB adjacent to the superior cerebellar peduncle, and the rostral two-thirds of the KF. Moderate to weak immunostaining was present in the superior, central, and dorsal lateral PB, the external medial PB, the medioventral part of the medial PB, and caudally in the KF. In contrast, remaining nuclei such as the external lateral PB and the waist area were essentially devoid of Gly-ir profiles, GlyT2-ir, and GlyRα1-ir. Immunoreactivity for GlyT1 was evenly distributed throughout all nuclei of the medial and lateral PB, including the external lateral PB and the waist area, while the KF was only weakly stained. Our data provide evidence that glycinergic mechanisms might play a role for neural processing in most nuclei of the PB and in the KF. Only the external lateral PB and the waist area are apparently not subject to glycinergic inhibition.     

Glycine, glycine receptor subunit and glycine transporters in the rat parabrachial and Kölliker-Fuse nuclei

In the present study, we investigated the expression and distribution of key molecules in the parabrachial (PB) and K?lliker-Fuse nuclei (KF) that determine glycinergic signal transduction. By means of immunocytochemistry, we analyzed the amino acid glycine (Gly), the glycine transporters 1 and 2 (GlyT1, GlyT2), and the ligand binding glycine receptor-subunit alpha 1 (GlyR alpha 1). Gly-immunoreactivity (-ir) was mainly found in varicose fibers and presumed terminal boutons; Gly-ir cell bodies were only occasionally seen. Immunoreactivity for GlyT2 was located in axons while GlyT1-staining was diffuse in the neuropil. Immunolabeling for GlyR alpha 1 occurred mostly as granular staining diffusely distributed throughout the neuropil. Only in the superior lateral PB, the lateral crescent of the PB, and caudally in the KF did GlyR alpha 1-ir outline cell bodies and primary and higher-order dendrites. Furthermore, our data demonstrate a distinct codistribution of immunoreactivities for Gly, GlyT2. and GlyR alpha 1 in a specific set of PB nuclei and in the KF. Strong staining was consistently seen in the internal lateral PB, the ventral lateral PB, the lateral crescent, the medial PB adjacent to the superior cerebellar peduncle, and the rostral two-thirds of the KF. Moderate to weak immunostaining was present in the superior, central, and dorsal lateral PB, the external medial PB, the medioventral part of the medial PB, and caudally in the KF. In contrast, remaining nuclei such as the external lateral PB and the waist area were essentially devoid of Gly-ir profiles, GlyT2-ir, and GlyR alpha 1-ir. Immunoreactivity for GlyT1 was evenly distributed throughout all nuclei of the medial and lateral PB, including the external lateral PB and the waist area, while the KF was only weakly stained. Our data provide evidence that glycinergic mechanisms might play a role for neural processing in most nuclei of the PB and in the KF. Only the external lateral PB and the waist area are apparently not subject to glycinergic inhibition.     

含酪氨酸羟化酶的神经元在猴延髓内脏带内的分布及形态特点

为观察含酪氨酸羟化酶（ＴＨ）阳性神经元在猴延髓内脏带内的分布及形态特点，使用免疫组织化学方法对３只恒河猴的延髓中尾段进行了研究。结果证明，延髓中尾段的ＴＨ阳性神经元集中分布于从背内侧至腹外侧的弧形带状区－－人脏带内（ＭＶＺ）。该区可分为背内侧部、腹外侧部和中间部。在背内侧部，ＴＨ阳性结构主要分布于迷走神经前运动核、最后区、孤束核的连合亚核、胶状质亚核和内侧亚核。在腹外侧部，由发愤侧向吻侧范围逐渐扩     

Connections of the anterior ectosylvian visual area (AEV)

Summary We have previously described a visual area situated in the cortex surrounding the deep infolding of the anterior ectosylvian sulcus of the cat (Mucke et al. 1982). Using orthograde and retrograde transport methods we now report anatomical evidence that this anterior ectosylvian visual area (AEV) is connected with a substantial number of both cortical and subcortical regions. The connections between AEV and other cortical areas are reciprocal and, at least in part, topographically organized: the rostral AEV is connected with the bottom region of the presylvian sulcus, the lower bank of the cruciate sulcus, the rostral part of the ventral bank of the splenial sulcus, the rostral portion of the lateral suprasylvian visual area (LS) and the lateral bank of the posterior rhinal sulcus; the caudal AEV is connected with the bottom region of the presylvian sulcus, the caudal part of LS, the ventral part of area 20 and the lateral bank of the posterior rhinal sulcus. Subcortically, AEV has reciprocal connections with the ventral medial thalamic nucleus (VM), with the medial part of the lateralis posterior nucleus (LPm), as well as with the lateralis medialis-suprageniculate nuclear (LM-Sg) complex. These connections are also topographically organized with more rostral parts of AEV being related to more ventral portions of the LPm and LM-Sg complex. AEV also projects to the caudate nucleus, the putamen, the lateral amygdaloid nucleus, the superior colliculus, and the pontine nuclei. It is concluded that AEV is a visual association area which functionally relates the visual with both the motor and the limbic system and that it might play a role in the animal's orienting and alerting behavior.Abbreviations Ac aqueductus cerebri - AEs anterior ectosylvian sulcus - ALLS anterolateral lateral suprasylvian area - AMLS anteromedial lateral suprasylvian area - ASs anterior suprasylvian sulcus - Cd caudate nucleus - CL central lateral nucleus - Cl claustrum - Cos coronal sulcus - Crs cruciate sulcus - DLS dorsal lateral suprasylvian area - GI stratum griseum intermediale - GP stratum griseum profundum - IC inferior colliculus - LAm lateral amygdaloid nucleus - LGNd dorsal nucleus of lateral geniculate body - LGNv ventral nucleus of lateral geniculate body - Llc nucleus lateralis intermedius, pars caudalis - LM nucleus lateralis medialis - LPl nucleus lateralis posterior, pars lateralis - LPm nucleus lateralis posterior, pars medialis - Ls lateral sulcus - MD nucleus mediodorsalis - MG medial geniculate body - MSs middle suprasylvian sulcus - Ndl nucleus dorsolateralis pontis - Nl nucleus lateralis pontis - Np nucleus peduncularis pontis - Npm nucleus paramedianus pontis - Nrt nucleus reticularis tegmenti pontis - Nv nucleus ventralis pontis - Ped cerebral peduncle - PEs posterior ectosylvian sulcus - Pg periaqueductal gray - PLLS posterolateral lateral suprasylvian area - PMLS posteromedial lateral suprasylvian area - PSs presylvian sulcus - Pul pulvinar - Put putamen - R red nucleus - Sg suprageniculate nucleus - SN substantia nigra - Sps splenial sulcus - Syls sylvian sulcus - T trapezoid body - VA ventral anterior nucleus - VL ventral lateral nucleus - VLS ventral lateral suprasylvian area - VM ventral medial nucleus - VPL ventral posterolateral nucleus - VPM ventral posteromedial nucleus Sponsored by Max-Planck-Society during part of the studySponsored by Thyssen FoundationSponsored by Alexander von Humboldt-Foundation     

Collateralization of frontal eye field (medial precentral/anterior cingulate) neurons projecting to the paraoculomotor region,superior colliculus,and medial pontine reticular formation in the rat: a fluorescent double-labeling study

Summary Paired injections of fluorescent tracers (True Blue, Diamidino-Yellow) were made into the oculomotor complex (OMC) and medial pontine reticular formation (mPRF), and superior colliculus (SC) and mPRF, in adult rats to retrogradely label the cortical cells of origin of projections to these oculomotor-related brainstem structures. While large numbers of single-labeled cells in the medial frontal cortex projected only to the mPRF, the presence of many double-labeled cells in the dorsomedial shoulder cortex (medial precentral/anterior cingulate areas), the rat frontal eye field (FEF), indicated that this cortical region contains lamina V pyramid neurons whose axons collateralize to project to the region of the OMC, SC, and mPRF. The similarities of rat and monkey FEF connections, and their relevance to the control of eye movement, are discussed.Abbreviations AC anterior commissure - ACd anterior cingulate area, dorsal - ACv anterior cingulate area, ventral - AId anterior insular area, dorsal - AIv anterior insular area, ventral - BC brachium conjunctivum (superior cerebellar peduncle) - CP caudoputamen - DY Diamidino Yellow - IL infralimbic area - MAB medial accessory nucleus of Bechterew - MLF medial longitudinal fasciculus - mPRF medial pontine reticular formation - MO medial orbital area - OMC oculomotor complex - PAG periaqueductal gray - PrCl lateral precentral cortex - PrCm medial precentral cortex - PL prelimbic area - RN red nucleus - riMLF rostral interstitial nucleus of the MLF - rs rhinal sulcus - SC superior colliculus - TB True Blue - VLO ventrolateral orbital area     

Some topographical connections of the striate cortex with subcortical structures in Macaca fascicularis

Summary Subcortical connections of the striate cortex with the superior colliculus (SC), the lateral pulvinar (Pl), the inferior pulvinar (Pi) and the dorsal lateral geniculate nucleus (LG) were studied in the macaque monkey, Macaca fascicularis, following cortical injections of tritiated proline and/or horseradish peroxidase. All four structures were shown to receive topographically organized projections from the striate cortex. The exposed surface of the striate cortex was found to be connected to the rostral part of the SC and the caudal part of the LG. Injections of the exposed striate cortex close to its rostral border resulted in label in adjoining parts of the Pl and Pi. The ventral half and dorsal half of the calcarine fissure were connected with the medial and lateral parts of the SC, the ventrolateral and dorsomedial portions of the Pl and Pi and the lateral and medial parts of the LG, respectively. Injections located at the lateral posterior extreme of the calcarine fissure resulted in label at the optic disc representation in the LG. The horseradish peroxidase material demonstrated that LG neurons in all laminae and interlaminar zones project to the striate cortex.Abbreviations BIC brachium of the inferior colliculus - BSC brachium of the superior colliculus - C cerebellum - CG central grey - i interlaminar zone(s) of the dorsal lateral geniculate nucleus - IC inferior colliculus - ICc central nucleus of the inferior colliculus - LG dorsal lateral geniculate nucleus - m magnocellular layer(s) of the dorsal lateral geniculate nucleus - MG medial geniculate body - p parvocellular layer(s) of the dorsal lateral geniculate nucleus - P pulvinar complex - Pi inferior pulvinar - PG pregeniculate nucleus - Pl lateral pulvinar - Pm medial pulvinar - s superficial layer(s) of the dorsal lateral geniculate nucleus - SC superior colliculus - sgs stratum griseum superficiale of the superior colliculus - R reticular nucleus of the thalamus - VP ventroposterior group - 17 Area 17 Supported by NEI Grants EY-07007 (J. Graham) and EY-02686 (J.H. Kaas)     

Projections to the rostral reticular thalamic nucleus in the rat

Summary Afferent pathways to the rostral reticular thalamic nucleus (Rt) in the rat were studied using anterograde and retrograde lectin tracing techniques, with sensitive immunocytochemical methods. The analysis was carried out to further investigate previously described subregions of the reticular thalamic nucleus, which are related to subdivisions of the dorsal thalamus, in the paraventricular and midline nuclei and three segments of the mediodorsal thalamic nucleus. Cortical inputs to the rostral reticular nucleus were found from lamina VI of cingulate, orbital and infralimbic cortex. These projected with a clear topography to lateral, intermediate and medial reticular nucleus respectively. Thalamic inputs were found from lateral and central segments of the mediodorsal nucleus to the lateral and intermediate rostral reticular nucleus respectively and heavy paraventricular thalamic inputs were found to the medial reticular nucleus. In the basal forebrain, afferents were found from the vertical and horizontal limbs of the diagonal band, substantia innominata, ventral pallidum and medial globus pallidus. Brainstem projections were identified from ventrolateral periaqueductal grey and adjacent sites in the mesencephalic reticular formation, laterodorsal tegmental nucleus, pedunculopontine nucleus, medial pretectum and ventral tegmental area. The results suggest a general similarity in the organisation of some brainstem Rt afferents in rat and cat, but also show previously unsuspected inputs. Furthermore, there appear to be at least two functional subdivisions of rostral Rt which is reflected by their connections with cortex and thalamus. The studies also extend recent findings that the ventral striatum, via inputs from the paraventricular thalamic nucleus, is included in the circuitry of the rostral Rt, providing further evidence that basal ganglia may function in concert with Rt. Evidence is also outlined with regard to the possibility that rostral Rt plays a significant role in visuomotor functions.Abbreviations ac anterior commissure - aca anterior commissure, anterior - Acb accumbens nucleus - AI agranular insular cortex - AM anteromedial thalamic nucleus - AV anteroventral thalamic nucleus - BST bed nucleus of stria terminalis - Cg cingulate cortex - CG central gray - CL centrolateral thalamic nucleus - CM central medial thalamic nucleus - CPu caudate putamen - DR dorsal raphe nucleus - DTg dorsal tegmental nucleus - EP entopeduncular nucleus - f fornix - Fr2 Frontal cortex, area 2 - G gelatinosus thalamic nucleus - GP globus pallidus - Hb habenula - HDB horizontal limb of diagonal band - IAM interanterodorsal thalamic nucleus - ic internal capsule - INC interstitial nucleus of Cajal - IF interfascicular nucleus - IL infralimbic cortex - IP interpeduncular nucleus - LC locus coeruleus - LDTg laterodorsal tegmental nucleus - LH lateral hypothalamus - LHb lateral habenular nucleus - ll lateral lemniscus - LO lateral orbital cortex - LPB lateral parabrachial nucleus - MD mediodorsal thalamic nucleus - MDL mediodorsal thalamic nucleus, lateral segment - Me5 mesencephalic trigeminal nucleus - MHb medial habenular nucleus - mlf medial longitudinal fasciculus - MnR median raphe nucleus - MO medial orbital cortex - mt mammillothalamic tract - OPT olivary pretectal nucleus - pc posterior commissure - PC paracentral thalamic nucleus - PF parafascicular thalamic nucleus - PPTg pedunculopontine tegmental nucleus - PrC precommissural nucleus - PT paratenial thalamic nucleus - PV paraventricular thalamic nucleus - PVA paraventricular thalamic nucleus, anterior - R red nucleus - Re reuniens thalamic nucleus - RRF retrorubral field - Rt reticular thalamic nucleus - Scp superior cerebellar peduncle - SI substantia innominata - sm stria medullaris - SNR substantia nigra, reticular - st stria terminalis - TT tenia tecta - VL ventrolateral thalamic nucleus - VO ventral orbital cortex - VP ventral pallidum - VPL ventral posterolateral thalamic nucleus - VTA ventral tegmental area - 3 oculomotor nucleus - 3V 3rd ventricle - 4 trochlear nucleus     

Connections between the supratemporal and its rostral areas, and the posterior thalamic region in the monkey: a retrograde HRP study.

Connections between the anterior half of the superior temporal gyrus (Ts) and the supratemporal plane (STP) in the Sylvian fissure, and the posterior thalamic region in the monkey were studied after retrograde transport of horseradish peroxidase (HRP). HRP injections into the Ts resulted in labeled cells in the posterodorsal division of the principal medial geniculate complex (GMpd), the suprageniculate and limitans nuclei, and the medial part of the medial nucleus of the pulvinar complex. HRP injections into the rostral Ts led to labeling in the posterior extremity of the GMpd, whereas injections into the caudal Ts resulted in labeling in the rostral GMpd. HRP injections into the area of transition between the Ts and STP led to labeling in the ventral part of the ventral division of the principal medial geniculate complex (GMv) and in the GMpd. HRP injections into the rostral STP led to labeling in the lateral part of the GMv, the anterodorsal division of the principal medial geniculate complex (GMad), and the lateral division of the posterior nucleus (Pol). HRP injections into the more caudal part of the STP yielded labeling in the more dorsomedial part of the GMv, Pol, and GMad. HRP injections into the lip of the STP yielded labeling in the GMv, Pol, GMad, and GMpd.     

大鼠中脑导水管周围灰质向三叉神经脊束核尾侧亚核的5-羟色胺能投射

大鼠中脑导水管周围灰质(PAG)向三又神经脊束核尾侧亚核(Sp 5 C)投射的起源细胞在其吻、中、尾三个部分的分布不同,且由尾段向吻段有从腹侧向背侧移行的趋势。尾段的HRP逆标细胞主要位于PAG的腹外侧区、内侧区腹侧部;中段的标记细胞较多,主要见于腹外侧区、背侧区和背外侧区腹侧部,尚可见一些顺行标记的终末;吻段的标记细胞主要位于背外侧区,在上丘深层、Cajal氏中介核、Darkschewitsch氏核内,也可见标记细胞。标记细胞和终末均主要位于注射侧的PAG内。PAG向Sp 5 C投射的5-羟色胺(5-HT)样神经元主要位于PAG的中、尾段的腹外侧区和内侧区腹侧部。中段的双标细胞占全部双标细胞数的57％,尾段占41％,吻段占2％。在背中缝核(DR)内,亦可见到一些双标细胞。PAG内的双标细胞占其HRP标记细胞总数的37％,但仅占5-HT样阳性细胞总数的4.5％。标记细胞主要为中型(20—30μm)梭形及三角形,小型(<20μm)梭形和大型(>30μm)多角形细胞较少见。     

An autoradiographic study of topographical relationships between pallidal and cerebellar projections to the cat thalamus

Summary Injections of ³H-leucine were made in the entopeduncular nucleus or dentate nucleus of the cerebellum in eight cats. The terminal projection zones of both pathways in the thalamus were studied using the sagittal plane and their relationships to one another as well as to cytoarchitectural boundaries of thalamic nuclei were compared. The data indicate that the territories controlled by the two projection systems are almost entirely segregated. The segregation is mainly along the antero-posterior axis as the main pallidal projection zone occupies the medio-ventral VA while the main dentate projection zone lies posterior to it in the VL. Furthermore, the dorsolateral part of the VA not occupied by pallidal projections receives dentate projections. In the VM, both afferent systems terminate in the lateral part of the nucleus with pallidal territory located anteriorly and dentate territory located posteriorly, again without overlap. As the delineations of nuclear subdivisions in the ventral thalamus of the cat have been a subject of some controversy, it is suggested that the boundaries of the VA, VL and VM in the cat thalamus be defined on the basis of basal ganglia and cerebellar projection zones.Abbreviations used in the Text and in Fig. 5 AM anterior medial nucleus - AV anterior ventral nucleus - BC brachium conjunctivum - CA anterior commissure - CC crus cerebri - CP posterior commissure - CD caudate nucleus - CE centrum medianum - CLN central lateral nucleus - DN dentate nucleus - EPN entopeduncular nucleus - FF Forel's field - FN fastigial nucleus - FR fasciculus retroflexus - HL lateral habenular nucleus - HM medial habenular nucleus - INA anterior interposite nucleus - INP posterior interposite nucleus - IC internal capsule - LD lateral dorsal nucleus - LG lateral geniculate body - MD medial dorsal nucleus - MTT mamillothalamic tract - NR red nucleus - OT optic tract - PAC paracentral nucleus - PF parafascicular nucleus - PV pulvinar - RT reticular thalamic nucleus - SM submedian nucleus - SN substantia nigra - SNr substantia nigra pars reticularis - STN subthalamic nucleus - VF ventral posterior nucleus - VA ventral anterior nucleus - VL ventral lateral nucleus - VM ventral medial nucleus - ZI zona incerta Supported in part by a grant from the American Parkinson Disease Association and NIH grant R01NS19280     

Thalamic afferents of area 4 and 6 in the dog: a multiple retrograde fluorescent dye study

In the present study, we compared the distribution of thalamocortical afferents of cortical area 4 to that of cortical area 6 in the dog, using fluorescent tracers. Multiple injections of combinations of two dyes (diamidino yellow dihydrochloride, Evans blue, fast blue, granular blue) were made into either the anterior and posterior sigmoid gyri or into the medial and lateral regions of the anterior sigmoid gyrus in the anesthetized dog. We found that the thalamic afferents of areas 4 and 6 arise from topographically organized bands of cells that traverse several thalamic nuclei and extend throughout the rostrocaudal extent of the thalamus. The most medial band included area 6-projecting neurons in the anterior nuclei, the rhomboid nucleus, the ventral anterior nucleus (VA), ventromedial nucleus (VM) and mediodorsal nucleus (MD). Within this band, cells projecting to medial area 6a tended to be more numerous in the anterior nuclei, anterior parts of VA and VM and anterior and caudal parts of MD. Fewer cells in MD but more cells in caudal parts of VA and VM projected to lateral area 6 a. Lateral bands of cells in central through lateral parts of VA and VL projected topographically to lateral area 4 on the anterior sigmoid gyrus and lateral through medial parts of postcruciate area 4. The most lateral band of cells in VL continued ventrally into the zona incerta. Area 4 also received input from VM and the central lateral (CL) and centrum medianum (CM) nuclei. Within regions of VA, VL and VM, cells from one band interspersed with cells from another, but there were very few double-labeled cells projecting to two cortical sites. When the present results are compared with our previous findings on the distribution of subcortical afferents to the motor thalamus, it appears that separate motor cortical areas may receive predominantly separate but also partially over-lapping pathways in the dog.Abbreviations AV Anterior ventral nucleus - AM anterior medial nucleus - Cb cerebellar nuclei - CeM central medial nucleus - CL central lateral nucleus - CM centrum medianum nucleus - EN entopeduncular nucleus - Hb habenula - LD lateral dorsal nucleus - MD mediodorsal nucleus - mt mammillothalamic tract - MV medioventral nucleus - Pf parafascicular nucleus - R reticular thalamic nucleus - rf retroflex fasciculus - Rh rhomboid nucleus - SN substantia nigra - VA ventral anterior nucleus - VL ventral lateral nucleus, principal division - VLd ventral lateral nucleus, dorsal division - VM ventral medial nucleus - VPL ventral posterior lateral nucleus - ZI zona incerta     

Tachykinin immunoreactivity in terminals of trigeminal afferent fibers in adult and fetal monkey thalamus

Summary Immunocytochemistry of fetal and adult monkey thalamus reveals a dense concentration of tachykinin immunoreactive fibers and terminals in the dorsolateral part of the VPM nucleus in which the contralateral side of the head, face and mouth is represented. The immunoreactive fibers enter the VPM nucleus from the thalamic fasciculus and electron microscopy reveals that they form large terminals resembling those of lemniscal axons and terminating in VPM on dendrites of relay neurons and on presynaptic dendrites of interneurons. Double labeling strategies involving immunostaining for tachykinins after retrograde labeling of brainstem neurons projecting to the VPM failed to reveal the origin of the fibers. The brainstem trigeminal nuclei, however, are regarded as the most likely sources of the VPM-projecting, tachykinin positive fibers.Abbreviations AB ambiguus nucleus - AN abducens nucleus - C cuneate nucleus - CD dorsal cochlear nucleus - CL central lateral nucleus - CM centre médian nucleus - D dendrite - DR dorsal raphe - DV dorsal vagal nucleus - EC external cuneate nucleus - FM medial longitudinal fasciculus - FN facial nucleus - G gracile nucleus - Gc gigantocellular reticular formation - HN hypoglossal nucleus - ICP inferior cerebellar peduncle - IO inferior olivary complex - LC locus coeruleus - LL lateral lemniscus - LM medial lemniscus - M5 motor trigeminal nucleus - NS solitary nucleus - OS superior olivary complex - P dendritic protrusion - Pb parabrachial nucleus - Pc parvocellular reticular formation - PLa anterior pulvinar nucleus - Pp prepositus hypoglossi nucleus - Ps presynaptic region - Py pyramidal tract - P5 principal sensory trigeminal nucleus - R reticular nucleus - RF reticular formation - RL lateral reticular nucleus - S5 spinal trigeminal nucleus - T terminal - T5 spinal trigeminal tract - VL lateral vestibular nucleus - VM medial vestibular nucleus - VMb basal ventral medial nucleus - VPI ventral posterior inferior nucleus - VPL ventral posterior lateral nucleus - VPM ventral posterior medial nucleus - VR ventral raphe - VS superior vestibular nucleus - VSp spinal vestibular nucleus - ZI zona incerta - 5 trigeminal nerve - 6 abducens nerve - 7 facial nerve     

Thalamic connections of the dorsal and ventral premotor areas in New World owl monkeys

Thalamic connections of two premotor cortex areas, dorsal (PMD) and ventral (PMV), were revealed in New World owl monkeys by injections of fluorescent dyes or wheat-germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). The injections were placed in the forelimb and eye-movement representations of PMD and in the forelimb representation of PMV as determined by microstimulation mapping. For comparison, injections were also placed in the forelimb representation of primary motor cortex (M1) of two owl monkeys. The results indicate that both PMD and PMV receive dense projections from the ventral lateral (VL) and ventral anterior (VA) thalamus, and sparser projections from the ventromedial (VM), mediodorsal (MD) and intralaminar (IL) nuclei. Labeled neurons in VL were concentrated in the anterior (VLa) and the medial (VLx) nuclei, with only a few labeled cells in the dorsal (VLd) and posterior (VLp) nuclei. In VA, labeled neurons were concentrated in the parvocellular division (VApc) dorsomedial to VLa. Labeled neurons in MD were concentrated in the most lateral and posterior parts of the nucleus. VApc projected more densely to PMD than PMV, especially to rostral PMD, whereas caudal PMD received stronger projections from neurons in VLx and VLa. VLd projected exclusively to PMD, and not to PMV. In addition, neurons labeled by PMD injections tended to be more dorsal in VL, IL, and MD than those labeled by PMV injections. The results indicate that both premotor areas receive indirect inputs from the cerebellum (via VLx, VLd and IL) and globus pallidus (via VLa, VApc, and MD). Comparisons of thalamic projections to premotor and M1 indicate that both regions receive strong projections from VLx and VLa, with the populations of cells projecting to M1 located more laterally in these nuclei. VApc, VLd, and MD project mainly to premotor areas, while VLp projects mainly to M1. Overall, the thalamic connectivity patterns of premotor cortex in New World owl monkeys are similar to those reported for Old World monkeys.     

Distribution of inferior olivary projections to the vestibular nuclei of albino rabbits

This study analyses the course and topography of olivo-vestibular projections originating in the dorsal cap, ventrolateral outgrowth and beta nucleus of albino rabbits. Rabbits were given either single pressure-injections of [3H]L-leucine (20 microCi in 50 nl) or single or multiple injections of 3-acetylpyridine (0.2-0.25 microliter of 27.5 micrograms/microliter in saline) into the medial aspect of the inferior olive. Brains from the former animals were processed for autoradiography after 2-3 days survival; brains from the latter animals were stained for degeneration with cupric-silver methods after a 16-24 h survival. In addition, four rabbits with kainic acid lesions of the flocculus were used to document flocculo-vestibular projections. Olivo-vestibular projections from the dorsal cap ventrolateral outgrowth, beta nucleus and the medial accessory olive diverge from olivo-cerebellar projections at the caudal margin of the flocculus stalk, and course medially in a broad sheet. Fibers (1) ascend in the superior fascicle, with flocculo-vestibular projections, to the superior vestibular nucleus, (2) enter the medial fascicle, with flocculo-vestibular fibers, and course along the dorsolateral border of the 4th ventricle to innervate a distinct rostral subdivision of the medial vestibular nucleus, and (3) enter the lateral fascicle, with flocculo-vestibular fibers, to terminate in pars alpha and beta of the lateral vestibular nucleus and the caudal subdivision of the medial vestibular nucleus. Comparison of different injection cases indicate that the caudal half to two-thirds of the dorsal cap contributes projections to the rostral medial vestibular nucleus, centrolateral and dorsomedial aspects of the superior vestibular nucleus, and a projection to both central and dorsal aspects of the caudal medial vestibular nucleus. By contrast, the rostral third to half of the dorsal cap-ventrolateral outgrowth projects sparsely to the rostral medial vestibular nucleus, contributing dense projections to the central aspect of the superior vestibular nucleus and dorsomedial and lateral regions in the caudal medial vestibular nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)     

Target neurons of floccular caudal zone inhibition in Y-group nucleus of vestibular nuclear complex

Extracellular unit spikes were recorded in and around the Y-group nucleus in the anesthetized cat. Target (T) neurons of floccular caudal zone inhibition were identified by observing cessation of their spontaneous discharges following stimulation of the floccular caudal zone. The axonal trajectories of the T neurons to the rostral brain stem were studied by observing the antidromic responses of single neurons during systematic tracking with a stimulating microelectrode in the brain stem. The axons of the T neurons pass through a region closely ventral to the lateral part of the brachium conjunctivum (BC), continue rostrally in a region between the BC and the lateral lemniscus, arch medially around the rostral part of the nucleus reticularis tegmenti pontis, cross the midline, continue to the contralateral side by about 1.5 mm lateral from the midline, arch rostrally, run in the central tegmental field on the contralateral side, arch dorsomedially around the caudal pole of the red nucleus, and enter the contralateral oculomotor nucleus (OMN) from the ventrolateral side. In the caudal half of the contralateral OMN, the axons of the T neurons branch out and terminate. The T neurons were exclusively located in the dorsal subdivision of the Y-group nucleus (DY), whereas some were in the medial part of the subnucleus lateralis parvocellularis (SLP, Ref. 12) of the lateral cerebellar nucleus. T neurons were not found in the ventral subdivision of the Y-group nucleus (VY). Differences in neuronal connections between the DY and VY neurons were investigated by observing responses of single neurons to stimulation of the contralateral OMN, the ipsilateral floccular caudal zone, the ipsilateral eighth nerve (i8N), and the contralateral eighth nerve (c8N). Most neurons in the DY and the adjacent medial part of the SLP, receiving inhibitory inputs from the ipsilateral flocculus (exclusively from the caudal zone), project to the contralateral OMN, and about one-half of these neurons receive polysynaptic inputs from the i8N and the c8N. On the other hand, most neurons in the VY receive monosynaptic inputs from the i8N, and some of these neurons project to the ipsilateral flocculus. The neuronal tract via the ventral part of the pontine tegmentum demonstrated in the present experiments is distinct from the classically established vestibulooculomotor tracts via the BC, the medial longitudinal fasciculus, or the ascending tract of Deiters. We call this tract the 'crossing ventral tegmental tract'. Previously, we reported that electrical stimulation of the caudal zone elicited conjugate downward eye movement.(ABSTRACT TRUNCATED AT 400 WORDS)     

A lectin horseradish peroxidase study of the origin of ascending fibers in the medial forebrain bundle of the rat. The upper brainstem

The origins of projections within the medial forebrain bundle from the upper brainstem were examined with the horseradish peroxidase technique. Labeled cells were found in approximately 15 upper brainstem nuclei following injections of a conjugate of horseradish peroxidase and wheat germ agglutinin at various levels of the medial forebrain bundle. Labeled nuclei included (from caudal to rostral): dorsal and ventral parabrachial nuclei; Kolliker-Fuse nucleus; dorsolateral tegmental nucleus; A7 (lateral pontine tegmentum medial to lateral lemniscus); median and dorsal raphe nuclei; distinct group of cells oriented mediolaterally in the dorsal pontine tegmentum below the central gray; B9 (ventral midbrain tegmentum dorsal to medial lemniscus); retrorubral nucleus; nucleus of Darkschewitsch, interfascicular nucleus; rostral and caudal linear nuclei; ventral tegmental area; medial part of substantia nigra, pars compacta; and the supramammillary nucleus. With the exception of the ventral parabrachial nucleus, Kolliker-Fuse, A7, B9 and substantia nigra, pars compacta, each of the nuclei mentioned above sent strong projections along the medial forebrain bundle to the rostral forebrain. Sparse labeling was observed throughout the pontine and midbrain reticular formation. With the exception of the dorsal raphe nucleus, projections to the most anterior regions of the medial forebrain bundle (level of the anterior commissure) essentially only arose from presumed dopamine-containing nuclei-retrorubral nucleus (A8 area), interfascicular nucleus, rostral and caudal linear nuclei, substantia nigra pars compacta, and ventral tegmental area. Evidence was reviewed indicating that major forebrain sites of termination for these dopaminergic nuclei are structures that have been collectively referred to as the 'ventral striatum'. It is concluded from the present findings that several pontine and mesencephalic cell groups are in a position to exert a strong, direct effect on structures in the anterior forebrain and that the medial forebrain bundle is the main communication route between the upper brainstem and the forebrain.     

An analysis of potentially converging inputs to the rostral ventral thalamic nuclei of the cat

Summary Potentially convergent inputs to cerebellar-receiving and basal ganglia-receiving areas of the thalamus were identified using horseradish peroxidase (HRP) retrograde tracing techniques. HRP was deposited iontophoretically into the ventroanterior (VA), ventromedial (VM), and ventrolateral (VL) thalamic nuclei in the cat. The relative numbers of labeled neurons in the basal ganglia and the cerebellar nuclei were used to assess the extent to which the injection was in cerebellar-receiving or basal ganglia-receiving portions of thalamus. The rostral pole of VA showed reciprocal connections with prefrontal portions of the cerebral cortex. Only the basal ganglia and the hypothalamus provided non-thalamic input to modulate these cortico-thalamo-cortical loops. In VM, there were reciprocal connections with prefrontal, premotor, and insular areas of the cerebral cortex. The basal ganglia (especially the substantia nigra), and to a lesser extent, the posterior and ventral portions of the deep cerebellar nuclei, provided input to VM and may modulate these corticothalamo-cortical loops. The premotor cortical areas connected to VM include those associated with eye movements, and afferents from the superior colliculus, a region of documented importance in oculomotor control, also were labeled by injections into VM. The dorsolateral portion of the VA-VL complex primarily showed reciprocal connections with the medial premotor (area 6) cortex. Basal ganglia and cerebellar afferents both may modulate this cortico-thalamo-cortical loop, although they do not necessarily converge on the same thalamic neurons. The cerebellar input to dorsolateral VA-VL was from posterior and ventral portions of the cerebellar nuclei, and the major potential brainstem afferents to this region of thalamus were from the pretectum. Mid- and caudo-lateral portions of VL had reciprocal connections with primary motor cortex (area 4). The dorsal and anterior portions of the cerebellar nuclei had a dominant input to this corticothalamo-cortical loop. Potentially converging brainstem afferents to this portion of VL were from the pretectum, especially pretectal areas to which somatosensory afferents project.List of Abbreviations AC central amygdaloid nucleus - AL lateral amygdaloid nucleus - AM anteromedial thalamic nucleus - AV anteroventral thalamic nucleus - BC brachium conjunctivum - BIC brachium of the inferior colliculus - Cd caudate nucleus - CL centrolateral thalamic nucleus - CM centre median nucleus - CP cerebral peduncle - CUN cuneate nucleus - DBC decussation of the brachium conjunctivum - DR dorsal raphe nuclei - EC external cuneate nucleus - ENTO entopeduncular nucleus - FN fastigial nucleus - FX fornix - GP globus pallidus - GR gracile nucleus - IC internal capsule - ICP inferior cerebellar peduncle - IP interpeduncular nucleus - IVN inferior vestibular nucleus - LD lateral dorsal thalamic nucleus - LGN lateral geniculate nucleus - LH lateral hypothalamus - LP lateral posterior thalamic complex - LRN lateral reticular nucleus - LVN lateral vestibular nucleus - MB mammillary body - MD mediodorsal thalamic nucleus - MG medial geniculate nucleus - ML medial lemniscus - MLF medial lengitudinal fasciculus - MT mammillothalamic tract - MVN medial vestibular nucleus - NDBB nucleus of the diagonal band of Broca - NIA anterior nucleus interpositus - NIP posterior nucleus interpositus - OD optic decussation - OT optic tract - PAC paracentral thalamic nucleus - PPN pedunculopontine region - PRO gyrus proreus - PRT pretectal region - PT pyramidal tract - PTA anterior pretectal region - PTM medial pretectal region - PTO olivary pretectal nucleus - PTP poterior pretectal region - Pul pulvinar nucleus - Put putamen - RF reticular formation - RN red nucleus - Rt reticular complex of the thalamus - S solitary tract - SCi superior colliculus, intermediate gray - SN substantia nigra - ST subthalamic nucleus - VA ventroanterior thalamic nucleus - VB ventrobasal complex - VL ventrolateral thalamic nucleus - VM ventromedial thalamic nucleus - III oculomotor nucleus - IIIn oculomotor nerve - 5S spinal trigeminal nucleus - 5T spinal trigeminal tract - VII facial nucleus     

Projections from the rostral mesencephalic reticular formation to the spinal cord

Summary Eye and head movements are strongly interconnected, because they both play an important role in accurately determining the direction of the visual field. The rostral brainstem includes two areas which contain neurons that participate in the control of both movement and position of the head and eyes. These regions are the caudal third of Field H of Forel, including the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and the interstitial nucleus of Cajal with adjacent reticular formation (INC-RF). Lesions in the caudal Field H of Forel in monkey and man result in vertical gaze paralysis. Head tilt to the opposite side and inability to maintain vertical eye position follow lesions in the INC-RF in cat and monkey. Projections from these areas to extraocular motoneurons has previously been observed. We reported a study of the location of neurons in Field H of Forel and INC-RF that project to spinal cord in cat. The distribution of these fiber projections to the spinal cord are described. The results indicate that: 1. Unlike the neurons projecting to the extra-ocular muscle motoneurons, the major portion of the spinally projecting neurons are not located in the riMLF or INC proper but in adjacent areas, i.e. the ventral and lateral parts of the caudal third of the Field H of Forel and in the INCRF. A few neurons were also found in the nucleus of the posterior commissure and ventrally adjoining reticular formation. 2. Neurons in caudal Field H of Forel project, via the ventral part of the ventral funiculus, to the lateral part of the upper cervical ventral horn. This area includes the laterally located motoneuronal cell groups, innervating cleidomastoid, clavotrapezius and splenius motoneurons. At lower cervical levels labeled fibers are distributed to the medial part of the ventral horn. Projections from the caudal Field H of Forel to thoracic or more caudal spinal levels are sparse. 3. Neurons in the INC-RF, together with a few neurons in the area of the nucleus of the posterior commissure, project bilaterally to the medial part of the upper cervical ventral horn, via the dorsal part of the ventral funiculus. This area includes motoneurons innervating prevertebral flexor muscles and some of the motoneurons of the biventer cervicis and complexus muscles. Further caudally, labeled fibers are distributed to the medial part of the ventral horn (laminae VIII and adjoining VII) similar to the projections of Field H of Forel. A few INC-RF projections were observed to low thoracic and lumbosacral levels. It is argued that the neurons in the caudal Field H of Forel, which project to the spinal cord are especially involved in the control of those fast vertical head movements which occur in conjunction with saccadic eye movements. In contrast the INC-RF projections to the spinal cord are responsible for slower, smaller movements controlling the position of the head in the vertical plane.Abbreviations Aq aquaduct of Sylvius - BIC brachium of the inferior colliculus - CGL lateral geniculate body - CGLd lateral geniculate body (dorsal part) - CGLv lateral geniculate body (ventral part) - CGM medial geniculate body - CGMd medial geniculate body, dorsal part - CGMint medial geniculate body, interior division - CGMp medial geniculate body, principal part - CM centromedian thalamic nucleus - CP posterior commissure - CS superior colliculus - D nucleus of Darkschewitsch - EW nucleus Edinger-Westphal - F fornix - FR/fRF fasciculus retroflexus - Hab habenular nucleus - HPA posterior hypothalamus area - HT hypothalamus - IN interpeduncular nucleus - INC interstitial nucleus of Cajal - LD nucleus lateralis dorsalis of the thalamus - LHA lateral hypothalamic area - LP lateral posterior nucleus - LV lateral ventricle - MB mammillary body - MC nucleus medialis centralis of the thalamus - MD nucleus medialis dorsalis of the thalamus - ML medial lemniscus - MTN medial terminal nucleus - ND nucleus of Darkschewitsch - NOT nucleus of the optic tract - NOTL lateral nucleus of the optic tract - NOTM medial nucleus of the optic tract - OL olivary pretectal nucleus - OT optic tract - PAG periaqueductal gray - PC pedunculus cerebri - PCN/NPC nucleus of the posterior commissure - PP posterior pretectal nucleus - PTA anterior pretectal nucleus - PTM medial pretectal nucleus - Pul pulvinar nucleus of the thalamus - PV posterior paraventricular nucleus of the thalamus - PVG periventricular gray - R reticular nucleus of the thalamus - riMLF rostral interstitial nucleus of the MLF - RN red nucleus - SM stria medullaris - SN substantia nigra - ST subthalamic nucleus - STT stria terminalis - SUB subiculum - VB ventrobasal complex of the thalamus - VTA ventral tegmental area of Tsai - ZI zona incerta - III oculomotor nucleus On leave of absence from Dept. Anatomy Erasmus University, Rotterdam, The Netherlands     

The corticothalamic projection from the gyrus proreus and the medial wall of the rostral hemisphere in the cat an experimental study with silver impregnation methods

Summary The corticothalamic projections from the gyrus proreus and the medial wall of the rostral hemisphere have been studied in the cat with the silver method of Nauta. The gyrus proreus projects upon the following nuclei (for abbreviations, see list on page 133), ipsilateral R, VA, VM, VL, MD, Pc, CL, CM, Pf, VPM, VPMpc. VPI and to the contralateral principal nucleus of the trigeminal nerve. The medial wall of the rostral hemisphere projects bilaterally upon R, VA, VM, VL, MD, Pc, CL, CM, Pf, VPM, VPMpc, VPI, VPL, the dorsal column nuclei and the principal nucleus of the trigeminal nerve. The ipsilateral thalamic projection is more abundant than the contralateral. The latter appears to increase in amount as the lesion is placed successively more ventrally on the medial wall of the rostral hemisphere. Some degenerating fibers cross in the corpus callosum and descend in the contralateral internal capsule but the majority cross in the dorsal part of the anterior commissure and reach the medial aspect of the anterior limb of the contralateral internal capsule. A somatotopical organization of the medial wall of the rostral hemisphere has been demonstrated. The rostrocaudal part projects upon the ipsilateral VPL lateralis (VPLl) and nucleus cuneatus and the contralateral nucleus gracilis and VPL medialis (VPLm). The caudal part of this cortical area sends fibers bilaterally to VPM, VPMpc, and the principal nucleus of the trigeminal nerve. The intermediate part, which also includes agranular cortex on the medial wall, projects upon ispsilateral VPLm and nucleus gracilis and upon contralateral VPLl and nucleus cuneatus. — The fibers to the ventro-basal complex, dorsal column nuclei and the principal nucleus of the trigeminal nerve are rather thick. The corticofugal fibers to the other thalamic nuclei are quite thin. — The findings are discussed in light of relevant anatomical and physiological observations in the literature and special emphasis has been laid on reported observations on the supplementary motor area.     

Morphological characteristics of the A10 catecholaminergic group of neurons in the human midbrain

The authors examined ten serially sectioned human midbrains stained with luxol fast blue and/or cresyl violet. They found the neuromelanin-containing neurons in the central (CL) and rostral (RL) linear nuclei, the interfascicular (IF), the paranigral (PN), and the parabrachial pigmented (PB) nuclei, as well as in the medial longitudinal fasciculus and the dorsal nucleus of the raphe. The CL nucleus measured 4.7 mm x 1.9 mm, the RL 2.9 mm x 0.6 mm, the IF 2.8 mm x 0.6 mm, the PN 1.3 mm x 0.8 mm, and the PB 4.4 mm x 0.7 mm. The number of pigmented neurons per section was 9.4 in the CL, 13.5 in the RL, 51.7 in the IF, 41.8 in the PN, and 33.1 in the PB nucleus. The pigmented neurons, which were fusiform, oval or multipolar, ranged from 9.3 microns x 9.0 microns to 62.0 microns x 25.0 microns in size. Clustering of the cells was most prominent in the IF and PN nuclei, as well as in the lateral parts of the PB and RL nuclei. The authors concluded that: 1. the CL and PB were the largest nuclei; 2. the greatest cellular density was in the IF and PN nuclei; 3. the largest pigmented neurons were present in the RL and PB nuclei, and 4. the CL and RL nuclei were more complex than the other nuclei of the A10 catecholaminergic group.