Olivary projections to the cerebellar nuclei in the cat

Summary Projections from the inferior olive to the cerebellar nuclei have been studied in the cat using Nauta's silver technique. 1. Numerous degenerating terminals occur after lesions in the inferior olivary complex in the medial nuclei of both sides; the degeneration is considerably less in the subnucl. medialis parvicellularis of both sides. In the interpositus nuclei of both sides degenerating terminals are also abundant, especially in their dorsal and lateral parts. In the lateral nucleus a number of degenerating terminals are seen on both sides restricted to dorsal and lateral parts of the nuclei. Degeneration is scanty in the subnucl. lateralis parvicellularis. 2. Projection of the olivocerebellar fibers to the cerebellar nuclei is always bilateral. The fibers originate in the inferior olive and ascend mainly through the contralateral, however, some also through the ipsilateral restiform body. The olivocerebellar fibers that have crossed in the medulla terminate in the medial and the interpositus nuclei of both sides. It is suggested that the degenerating terminals found in the cerebellar nuclei are derived from collaterals of the olivocerebellar tract fibers.     

Projections from the lateral reticular nucleus to the cerebellar cortex and nuclei in the cat

Summary The fiber projection from the lateral reticular nucleus (LRN) to the cerebellum was examined in the cat. Electrolytic lesions were placed in a confined area of the LRN using a parapharyngeal approach, and the ensuing degeneration was studied in sections stained by the Nauta and the Fink-Heimer methods.Fibers from the LRN ascend the ipsilateral restiform body, terminating bilaterally but chiefly in the ipsilateral cerebellum. In the ipsilateral cortex projections were found to lobules I to V, with denser terminations in sublobules IVb to Ve. The projections are stronger in the intermediate-lateral zones than in the vermis proper. There is also a dense projection to sublobules VId and VIf and to the medialmost part of the simple lobule (HVI). Scanty termination was seen in the medialmost part of crus I. There is a moderate projection to the caudalmost folium of sublobule VIIb and to the rostral folia of sublobule VIIIa and the paramedian lobule. The contralateral projection by fibers crossed within the cerebellum is far less dense but clearcut in the anterior lobe, the rostral folia of lobule VI and the medial part of the simple lobule.In the ipsilateral nuclei strong projections were found to rostral portions of the medial nucleus (M) and the caudal two thirds of the anterior interpositus nucleus (IA) with predominance in the lateral part of the latter. A focal projection was found to rostrodorsal portions of the posterior interpositus nucleus (IP). No projection was found to the lateral nucleus (L). Contralaterally there is a weak projection to the rostral part of M and the medial parts of IA and IP.Abbreviations AL Anterior lobe - BP Brachium pontis - CD Subnucl. dorsalis of the nucl. medullae oblongatae centr. - CV Subnucl. ventralis of the nucl. medullae oblongatae centr. - Cr. I Crus I - Cr. II Crus II - F Flocculus - GL Granular layer - IA Anterior interpositus nucleus - IO Inferior olive - IP Posterior interpositus nucleus - LRN Lateral reticular nucleus - L Lateral nucleus - M Medial nucleus - ML Molecular layer - Pfd Paraflocculus dorsalis - Pfv Paraflocculus ventralis - Pm Paramedian lobule - RB Restiform body - SL Simple lobule - SMP Subnucleus medialis parvocellularis - ST Nucleus of the spinal trigeminal tract - XII Hypoglossal nerve nucleus     

Somatotopical organization of the projection from the nucleus interpositus anterior of the cerebellum to the red nucleus. An experimental study in the cat with silver impregnation methods

Summary Small lesions were done in various areas of the nucleus interpositus anterior (NIA) of the cerebellum, and the distribution of terminal degeneration was studied in the red nucleus with the methods of Nauta and Glees. The NIA projects to the contralateral red nucleus. Two principles of organization can be demonstrated in the projection: a caudorostral arrangement in the red nucleus corresponds to a mediolateral organization in the NIA and a mediolateral arrangement in the red nucleus corresponds to a caudorostral organization of the NIA. The latter distribution coincides with the somatotopical areas of the red nucleus defined by Pompeiano and Brodal (1957). Special attention has been paid to the questions of the subdivision of the cerebellar nuclei and of the course of the fibres issuing from the nuclei in the cerebellar hilus. The present findings on the projection of the NIA to the red nucleus have been correlated with recent anatomical and physiological data on the cerebellum and the red nucleus.Abbreviations BC brachium conjunctivum - c caudal - d dorsal - Ext extensor effects - Flex flexor effects - forel forelimb area - HB hook-bundle - Hb. P habenulo-peduncular tract - hindl hindlimb area - I lateral - m medial - NF nucleus fastigii or medialis - NIA nucleus interpositus anterior - NIP nucleus interpositus posterior - NL nucleus lateralis - r rostral - v ventral - III root fibres of the third nerve - IV fourth ventricle Fellow of the Canadian Medical Research Council.     

Topographic organization of the cerebellothalamic projections in the rat. An autoradiographic study

The topographical organization of the subnuclear projections towards the thalamus was studied with autographic methods in adult Wistar rats. The four cerebellar deep nuclei give rise to projections to the ventral region of the rostral thalamus. Most of the fibers end contralaterally, according to a topographical pattern; however, some fibers from each of the cerebellar nuclei recross the midline at the thalamic level and terminate ipsilaterally, within regions symmetric to those receiving the densest contralateral projection. These ipsilateral cerebellothalamic components arise in decreasing order from the caudal nucleus lateralis, the ventrocaudal nucleus medialis and the nucleus interpositus, respectively. The projections of the nucleus lateralis directed to the contralateral thalamus are topographically organized. (1) Within the nucleus ventralis lateralis, the rostral and caudal parts of the cerebellar nucleus lateralis project respectively to rostral and caudal regions; lateral and medial zones of the nucleus lateralis project, respectively, to medial and central aspects of the nucleus ventralis lateralis. (2) The nucleus ventralis medialis and particularly its caudal portion appears to receive the bulk of its afferents from the ventromedial portion of the nucleus lateralis including the "subnucleus lateralis parvocellularis". (3) The nucleus centralis lateralis receives fibers from most parts of the nucleus lateralis including the "dorsolateral hump". (4) The nucleus interpositus anterior projects to the dorsomedial aspect of the rostral nucleus ventralis lateralis. In the latter nucleus, the ventrolateral aspect of the central region receives projections in cases in which the nucleus interpositus posterior is largely involved. A particular emphasis is put on the different projections from the various subnuclear regions of the lateral nucleus. A comparison is attempted with the situation in the primates, particularly with regard to the question of the parvocellular subdivision of the lateral nucleus.     

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。     

Plasticity of cerebellar efferents after neonatal lesions in albino rats

In normal adult albino rats the interposed and dentate nuclei project to the contralateral red nucleus, zona incerta (ZI) lateral geniculate nucleus, pars ventralis (LGv), and the thalamic nuclei ventralis medialis (VM), ventralis anterior (VA), ventralis lateralis (VL) and medialis ventralis (MV). Following unilateral cerebellar hemispherectomy with removal of the major parts of the dentate and interposed nuclei at birth, 2 days, 3 days, 5 days and 10 days after birth, cerebellar efferents from the remaining opposite dentate and interposed nuclei were shown to project bilaterally to the red nucleus, ZI, LGV and the thalamic nuclei, VM, VA, VL, and MV. The density of anomalous projections to the various nuclei was greater in animals receiving their initial lesions within the first 5 days after birth, and very much less in animals first lesioned at 10 days postnatally. No anomalous fibre could be detected in animals lesioned at 15 days postnatally. The anomalous fibre formation was correlated with the apparent functional recovery of the animals lesioned within the first 10 days after birth.     

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

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

Developmental timetables and gradients of neurogenesis in cerebellar Purkinje cells and deep glutamatergic neurons: A comparative study between the mouse and the rat

The aim of this report is to determine whether the times of neuron origin and neurogenetic gradients of PCs and Deep cerebellar nucli (DCN) glutamatergic neurons are different between mice and rats. Purkinje cells (PCs) were analyzed in each compartment of the cerebellar cortex (vermis, paravermis, medial, and lateral hemispheres), and deep glutamatergic neurons at the level of the medialis, interpositus, and lateralis nuclei. Tritiated thymidine ([³H]TdR) autoradiography was applied on sections. The experimental rodents were the offspring of pregnant dams injected with [³H]TdR on embryonic days (E) 11–12, E12–13, E13–14, E14–15, E15–16, and E16–17. Our results indicate that systematic differences exist in the pattern of neurogenesis and the spatial location of cerebellar PCs and deep glutamatergic neurons between mice and rats. In mice, PCs and deep glutamatergic neurons neurogenesis extend from E10 to E14, with a predominance of neurogenesis on E12 for PCs, and on E12, E11, and E10 for the medialis, interpositus, and lateralis neurons, respectively. When neurogenesis in rats was considered, the data reveal that PCs and deep glutamatergic neurons production extends from E12 to E16, with a peak of production on E14 for PCs, and on E14, E13, and E12 for the medialis, interpositus, and lateralis neurons, respectively. Current data also indicate that, both in mice and rats, both types of macroneurons are generated according to a lateral-to-medial gradient. Thus, the lateral hemisphere and the lateralis nucleus present more early-generated neurons than the vermis and the medialis nucleus, which in their turn have more late-produced neurons.     

Cerebellotectal projections studied in cats with horseradish peroxidase or tritiated amino acids axonal transport

Summary After injections of horseradish peroxidase (HRP) into various parts of the superior colliculus (SC) in 14 cats, retrogradely labeled neurons were found in parts of all deep cerebellar nuclei. The present study demonstrated that there are three main origins of the cerebellotectal projections in regard to the locations of the cell bodies: (1) the caudal half approximately of the fastigial nucleus (NM) including the subnucleus medialis parvocellularis (SMP), (2) the ventral and lateral parts of the posterior interpositus nucleus (NIP), and (3) the ventral part of the dentate nucleus (NL) including the subnucleus lateralis parvocellularis (SLP).The pathways and terminations of these projections have also been shown autoradiographically. Thus, fibers from NM crossed within the cerebellum and terminated in the intermediate and deep gray layers of the bilateral SC. Fibers from NIP and NL passed within the superior cerebellar peduncle, which crossed in the tegmentum (decussation of the peduncle) and ended in the two layers of the contralateral SC. In addition, some cerebellofugal fibers were found to terminate in the nuclei interstitialis of Cajal and Darkschewitsch, as well as in parts of pretectum and thalamus.The tecto-ponto- (and olivo-) cerebellotectal loop (cf. Kawamura 1980) has been established morphologically and it is briefly commented on in correlation with the propagation of the teleceptive (optic and acoustic) impulses.Abbreviations AI Stratum album intermedium - AP Stratum album profundum - Cc Crus cerebri - CM Corpus mamillare - EW Nucleus of Edinger-Westphal - f.apm. Ansoparamedian fissure - Flm Fasciculus longitudinalis medialis - f.p.l. Posterolateral fissure - f.ppd. Prepyramidal fissure - f.pr. Fissura prima - f.p.s. Posterior superior fissure - f.sec. Fissura secunda - GI Stratum griseum intermedium - GP Stratum griseum profundum - GS Stratum griseum superficiale - L. Left - MG Medial geniculate body - ND Nucleus of Darkschewitsch - NIA Nucleus interpositus anterior - Nint Nucleus interstitialis of Cajal - NIP Nucleus interpositus posterior - NL Nucleus lateralis (dentatus) - NL-NIA Transition area of nucleus lateralis (dentatus) and nucleus interpositus anterior - NM Nucleus fastigii - Npa Nucleus pretectalis anterior - Npc Nucleus of posterior commissure - Npm Nucleus pretectalis medialis - Npp Nucleus pretectalis posterior - NR Nucleus ruber - Nto Nucleus of optic tract - N.III Oculomotor nerve - O Stratum opticum - PC Posterior commissure - pm. Paramedian lobule - Pg Periaqueductal gray substance - R. Right - Rf Fasciculus retroflexus - SC Superior colliculus - SCC Commissure of SC - Z Stratum zonale - III Nucleus of oculomotor nerve - V, VI, VIIA, VIIB, VIIIA, VIIIB, IX Cerebellar lobules of Larsell Working in the Anatomical Department of Iwate Medical University for six months (several periods during the year 1981)     

Growth of fresh volumes and spontaneous cell death in the nuclei habenulae of albino rats during ontogenesis

Summary The growth of the nuclei habenulae medialis et lateralis of albino rats is described by monotonically increasing growth curves of fresh volumes during ontogenesis. The nucleus habenulae medialis matures earlier than the nucleus habenulae lateralis in the perinatal period. However, the two nuclei reach their final volume at about the same time. Simultaneous electron microscopic investigation reveals the phenomenon of spontaneous nerve cell degeneration within the nuclei habenulae during ontogenesis in spite of the non-overshooting growth curves for the habenular nuclei.Supported by Deutsche Forschungsgemeinschaft grants Zi 192/1 and 192/3     

Projections from the intracerebellar nuclei to the ventral midbrain tegmentum in the rat

The present study was undertaken to provide anatomical evidence, in the rat, for a direct projection from the cerebellum towards structures, other than the red nucleus, which belong to the ventral midbrain tegmentum, by using the retrograde as well as the anterograde horseradish peroxidase transport method. Following unilateral injection in the ventral midbrain tegmentum of horseradish peroxidase, free or conjugated to wheat germ agglutinin, sparing the red nucleus, retrogradely labeled neurons were found in the contralateral cerebellar lateral nucleus and, at lower density, in the interpositus nucleus. No labeled neurons were found in the fastigial nucleus of either side. Anterogradely labeled axons from lectin coupled horseradish peroxidase injection sites in the lateral and interpositus nuclei reached the contralateral ventral midbrain tegmentum. Terminal labeling was observed in the entire red nucleus as well as in the lateral division of the ventral tegmental area of Tsai, in the dorsal region of the substantia nigra pars compacta, and in the medial part of the retrorubral field. No terminal labeling was found in the caudal linear nucleus, interfascicular nucleus, peripeduncular nucleus, rostral linear nucleus of the raphe, substantia nigra pars lateralis and the substantia nigra pars reticulata. Terminal labeling was also not observed in the ventral midbrain tegmentum following horseradish peroxidase injection in lateral and interpositus nuclei of rats pretreated with kainic acid. In conclusion, it is noteworthy that, besides the red nucleus, the sole structures of ventral midbrain tegmentum receiving cerebellar efferents are those with a higher density of dopaminergic cells.     

Efferent fiber projections of the habenula and the interpeduncular nucleus. An experimental study in the opossum and cat

Summary A study of efferent fiber connections of the habenula and the inter-peduncular nucleus was conducted using anterograde degeneration techniques. Lesions were placed in the habenula of the opossum and the habenula and interpeduncular nucleus of the cat. Degeneration was studied by means of the Nauta and Fink-Heimer techniques.Fibers from the habenular nucleus of the opossum extended caudally and were traced bilaterally to the interpeduncular nucleus, dorsal tegmental nucleus of Gudden, deep (ventral) tegmental nucleus of Gudden, nucleus centralis superior and nucleus reticularis tegmenti pontis. Rostrally fibers were traced to the preoptic and septal region and the anterior and lateral hypothalamus.The medial and lateral habenular nuclei of the cat projected differentially to portions of the interpeduncular nucleus and the tegmental nuclei of Gudden. The medial habenular nucleus sent fibers to the paramedian subnucleus of the interpeduncular nucleus and to the deep tegmental nucleus; whereas the lateral habenular nucleus distributed to the apical and central subnuclei of the interpeduncular nucleus and the dorsal tegmental nucleus.Fibers from both the medial and lateral habenular nuclei were found to project bilaterally to the nucleus paraventricularis anterior, nucleus ventralis anterior, anterior medialis and anterior dorsalis of the thalamus, and the septal area.Fibers from the interpeduncular nucleus of the cat were represented bilaterally. Those passing rostral went to the lateral habenular nucleus, nucleus centromedianus and parafascicularis of the thalamus, and to the septal area. Those directed caudally projected to the nucleus centralis superior, and the dorsal and deep tegmental nucleus of Gudden.Abbreviations AC anterior commissure - AD nucleus anterior dorsalis - AM nucleus anterior medialis - AV nucleus anterior ventralis - BC brachium conjunctivum - CC corpus callosum - CD caudate nucleus - CI internal capsule - CL nucleus centralis lateralis - CM nucleus centromedianus - CP cerebral peduncle - DT dorsal tegmental nucleus (of Gudden) - EN entopeduncular nucleus - Fx fornix - GC central gray - GL lateral geniculate nucleus - GM medial geniculate nucleus - GP globus pallidus - HbPt habenulopeduncular tract - HVM ventromedial hypothalamic nucleus - IC inferior colliculus - IP interpeduncular nucleus - LHb lateral habenular nucleus - LL lateral lemniscus - LMN lateral mammillary nucleus - LP nucleus lateralis posterior - MD nucleus medialis dorsalis - MHb medial habenular nucleus - ML medial lemniscus - MMN medial mammillary nucleus - MP mammillary peduncle - NCM nucleus centralis medialis - OC optic chiasm - OT optic tract - Pf nucleus parafascicularis - Pul pulvinar - PUT putamen - RE nucleus reuniens - RN red nucleus - RPO preoptic area - RTP nucleus reticularis tegmenti pontisv (von Bechterew) - S stria medullaris - SC superior colliculus - SN substantia nigra - SPT septal area - VA nucleus ventralis anterior - VL nucleus ventralis lateralis - VM nucleus ventralis medialis - VPL nucleus ventralis posterolateralis - VPM nucleus ventralis posteromedialis - VT deep tegmental nucleus (of Gudden) - II optic nerve     

Connections to the lateral posterior-pulvinar thalamic complex from the reticular and ventral lateral geniculate thalamic nuclei: a topographical study in the cat

The projections from the reticular thalamic nucleus and the ventral lateral geniculate nucleus to the lateral posterior-pulvinar thalamic complex were studied in the adult cat using the retrograde transport of horseradish peroxidase. Small, stereotaxically guided injections of the enzyme were placed in the various nuclei of this complex, including the pulvinar, lateralis intermedius oralis, lateralis intermedius caudalis, lateralis posterior lateralis, lateralis posterior medialis and lateralis medialis nuclei. The distribution of labeled neurons indicates that these nuclei receive topographically organized projections from the reticular and ventral lateral geniculate nuclei. The pulvinar nucleus receives only very scarce projections from the reticular thalamic nucleus originating in its posterodorsal and posteroventral sectors. The reticular projection to the nucleus lateralis intermedius oralis is even sparser. The nuclei lateralis intermedius caudalis, lateralis posterior lateralis and lateralis posterior medialis receive substantial projections from the suprageniculate sector of the reticular thalamic nucleus. The nucleus lateralis medialis receives an abundant projection from the three sectors (suprageniculate, pregeniculate and infrageniculate) of the reticular thalamic nucleus. Except for the lateralis intermedius caudalis, all nuclei of the lateral posterior-pulvinar complex receive consistent projections from the ventral lateral geniculate nucleus, the nucleus lateralis medialis receiving the densest one. Our findings suggest that visual, auditory, somatosensory, motor and limbic impulses from thalamic nuclei and from primary sensory and association cortical areas modulate the activity of the nucleus lateralis medialis via the reticular thalamic nucleus. The remaining nuclei of the lateral posterior-pulvinar complex are mainly modulated by sectors of the reticular thalamic nucleus that receive afferent connections from visual structures. The intrathalamic projections arising from the ventral lateral geniculate nucleus may be the way through which visuomotor inputs reach the different components of the lateral posterior-pulvinar thalamic complex.     

The interposito-rubrospinal system. Anatomical tracing of a motor control pathway in the rat

The cerebello-rubromotor pathway, impinging on both spinal and facial motor nuclei, has been traced in the rat, using the bidirectional transport of horseradish peroxidase-wheat germ agglutinin conjugate. After injection of the tracer in the red nucleus (NR), retrograde labelling shows a topical arrangement of the cerebellorubral connection. The nucleus lateralis projects to the parvocellular NR (NRp) and the nucleus interpositus to the magnocellular NR (NRm). The nucleus interpositus anterior (NIA) reaches the entire NRm and this projection is topographically arranged: the medial NIA sends fibres ventrally, the lateral NIA dorsally. The medial two-thirds of the nucleus interpositus posterior (NIP) project only to the medial aspect of the NRm, with no apparent organization. No connection has been found between the lateral third of NIP and the NRm. After injection of the tracer in the spinal cord or the nucleus of the facial nerve, retrograde labelling is observed almost throughout the entire caudorostral extent of the NR, although labelling is more scant in NRp than in NRm. Rubrospinal and rubrofacial projections are somatotopically arranged in the dorsoventral direction: ventrolateral regions of NR reach the lumbar cord, medioventral regions the lower cervical levels, intermediary regions the upper cervical levels and finally the dorsalmost part of the NR projects to the nucleus of the facial nerve. After injection of the tracer in the cerebellar nuclei, anterograde labelling in the NR shows that interpositorubral connections determine two subregions in the NR: a lateral one under the exclusive control of the NIA, and a medial one under the control of both NIA-NIP afferents. It confirms in addition the topography of the NIA-NRm projection and shows the preponderant participation of the NIA afferents to the interpositorubral connection. Thus, it appears from our results that the cerebellorubral arrangement matches, to a great extent, the "rubromotor" efferent organization.     

Organization of transient projections from the primary somatosensory cortex to the cerebellar nuclei in kittens

Summary The organization of transient projections from the primary somatosensory cortex (SI) to the cerebellar nuclei was studied in neonatal cats. Tritiated amino acids were injected into the face, forelimb, or hindlimb areas of SI in 4 to 6-day-old kittens. The animals were killed 3 to 6 days later and their brains processed for autoradiography. Labeled axons were found bilaterally in the cerebellar nuclei, but, although the distribution of label was similar on both sides, the label was always much denser on the side of the injection. Each area of SI demonstrated a characteristic pattern of projection to the cerebellar nuclei. Neurons in the hindlimb area projected to the rostral part of the anterior interpositus nucleus, the caudal part of the posterior interpositus nucleus, and the medial quadrant of the dentate nucleus. Fibers from the forelimb area were directed to the caudal part of the anterior interpositus and the rostral part of the posterior interpositus. Projections from the face area terminated principally in the caudal pole of the posterior interpositus. A small transitional area between the interpositus and fastigial nuclei was labeled with all injections. These data indicate that transient neocortical projections to the deep nuclei are organized and that the somatotopy of these projections is similar to that of other cerebellar nuclear connections.     

The termination of the spinothalamic tract in the cat an experimental study with silver impregnation methods

Summary The termination of the spinothalamic tract (STT) in the cat has been studied light microscopically in Fink-Heimer and Nauta impregnated sections. Following lesions of the STT at various rostrocaudal levels of the spinal cord the degenerating fibres in the thalamus and subthalamus were mapped, mainly in transverse sections. The cervicothalamic tract was not injured by the lesions.The spinothalamic fibres enter the diencephalon through the mesencephalic reticular formation and terminate in the following regions: the medial portion of the magnocellular part of the medial geniculate body (MGmc), the ventrolateral portion of the medial part of the posterior nuclear complex (PO_m), the caudolateral and medial parts of the zona incerta (ZI), the nucleus centralis medialis (CeM), the nucleus parafascicularis (Pf), the lateral part of the nucleus centralis lateralis (CL), the medial and rostrolateral parts of the nucleus ventralis lateralis (VL). To reach these regions the fibres pass through the nucleus centrum medianum (CM), the nucleus subparafascicularis (SPf) and the nucleus paracentralis (Pc). The fibres that terminate in the VL pass through Forel's field H₁ and the external medullated lamina (EML). Conclusive results were not obtained concerning a termination in the CM. The spinothalamic fibres do not pass through nor terminate in the nucleus ventralis posterolateralis (VPL) and the nucleus reticularis (R). The VPL, defined as that portion of the ventral thalamus that receives terminal fibres from the dorsal column nuclei, has been found to extend rostrally only as far as Horsley-Clarke level anterior 10.5. The results strongly support the view that all the spinothalamic fibres terminate ipsilateral to their course in the ventral quadrant of the spinal cord. No signs of a somatotopical organization of the termination of the STT were found.List of Abbreviations Cd nucleus caudatus - CeM nucleus centralis medialis - CG circumaqueductal gray substance - CL nucleus centralis lateralis thalami - CM nucleus centrum medianum thalami - CP commissura posterior - CTT cervicothalamic tract - EML external medullated lamina - H₁ Forel's field H₁ - HP tractus habenulopeduncularis - LCN nucleus cervicalis lateralis - LG corpus geniculatum laterale - LP nucleus lateralis posterior thalami - MD nucleus medialis dorsalis thalami - MG corpus geniculatum mediale - MGmc corpus geniculatum mediale, pars magnocellularis - MGp corpus geniculatum mediale, pars principalis - ML medial lemniscus - MRF mesencephalic reticular formation - OT optic tract - Pc nucleus paracentralis thalami - Pf nucleus parafascicularis thalami - PO posterior group of thalamic nuclei - PO₁ lateral part of PO - PO_m medial part of PO - R nucleus reticularis thalami - SG nucleus suprageniculatus - STT spinothalamic tract - VA nucleus ventralis anterior - VL nucleus ventralis lateralis thalami - VM nucleus ventralis medialis thalami - VPI nucleus ventralis posterior inferior - VPL nucleus ventralis posterior lateralis thalami (VPL₁ + VPL_m) - VPL₁ lateral part of VPL - VPL_m medial part of VPL - VPM nucleus ventralis posterior medialis thalami - VPMpc parvocellular part of VPM - ZI zona incerta     

Diencephalic connections of the superior colliculus in the hedgehog tenrec

Using different tracer substances the pathways connecting the superior colliculus with the diencephalon were studied in the Madagascan hedgehog tenrec (Echinops telfairi), a nocturnal insectivore with tiny eyes, a small and little differentiated superior colliculus and a visual cortex with no obvious fourth granular layer. The most prominent tecto-thalamic projection terminated in the ipsilateral dorsal lateral geniculate nucleus. The entire region receiving contralateral retinal afferents was labeled with variable density. In addition, there was a widespread, homogeneously distributed collicular input to the lateralis posterior-pulvinar complex and a distinct tectal projection to the suprageniculate nucleus. The latter projections were bilateral with a clear ipsilateral predominance. Among the intra- and paralaminar nuclei the centralis lateralis complex was most heavily labeled on both sides, followed by the nucleus centralis medialis. The paralamellar portion of the nucleus medialis dorsalis and the nucleus parafascicularis received sparse projections. A clear projection to the nucleus ventralis medialis could not be demonstrated but its presence was not entirely excluded either. There were also projections to medial thalamic nuclei, particularly the reuniens complex and the nucleus paraventricularis thalami. The main tecto-subthalamic target regions were the zona incerta, the dorsal hypothalamus and distinct subdivisons of the ventral lateral geniculate nucleus. These regions also gave rise to projections to the superior colliculus, as did the intergeniculate leaflet. The pathways oriented toward the visual or frontal cortex and the projections possibly involved in limbic and circadian mechanisms were compared with the connectivity patterns reported in mammals with more differentiated brains. Particular attention was given to the tenrec's prominent tecto-geniculate projection, the presumed W- or K-pathway directed toward the supragranular layers.     

Afferents to the cerebellar nuclei from the cervical enlargement in the rat, as demonstrated with the Phaseolus vulgaris leucoagglutinin method

Injections of Phaseolus vulgaris leucoagglutinin into the cervical enlargement labeled spinocerebellar fibers in the rat cerebellar nuclei. Immunoreactive terminal axons and terminals were distributed in the medial nucleus, and the anterior interpositus and the posterior interpositus nucleus. The present study suggests that spinocerebellar neurons in the cervical enlargement (the medial lamina VI and the central lamina VII groups) project to the cerebellar nuclei.     

Impaired eyeblink conditioning in 78 kDa-glucose regulated protein (GRP78)/immunoglobulin binding protein (BiP) conditional knockout mice

Evidence grows that the cerebellum and its associated circuitry are the essential neural substrates for standard delay classical eyeblink conditioning. To further investigate the relative roles of the cerebellar cortex and nuclei in eyeblink conditioning, a novel mouse model with Purkinje cell atrophy was studied. The 78 kDa-glucose regulated protein, a chaperone molecule, was knocked out leading to postnatal Purkinje cell degeneration (Wang et al., 2010), and standard delay eyeblink conditioning was performed in the conditional knockout mice. Learning was impaired, yet not completely prevented. Histological studies showed a reduction in the cell number and the size of the anterior interpositus nucleus. When the anterior interpositus nucleus was lesioned bilaterally, eyeblink conditioning was completely prevented. The important roles of both cerebellar cortex and AIP nucleus in eyeblink conditioning were seen.     

家兔前庭核与脊髓的联系——HRP法研究

将HRP注入家兔颈、胸或腰髓的一侧灰质内,追踪前庭四核内的逆行标记细胞和顺行标记终支。发现同侧外侧核内标记细胞数量甚多,且具有体部定位规律。内侧核及降核的尾段标记细胞也较多,内侧核者甚为密集,它们投射到双侧脊髓的颈、胸、腰段,对侧多于同侧,无体部定位关系。降核的头段及在此平面的内侧核内也有一定数量的标记细胞,也投射到颈、胸、腰髓,同侧为主,无体部定位关系。上核内只有极少量标记细胞,主要投射到对侧颈髓。顺行标记终支于降核、内侧核的见端小范围内及外侧核的尾端背面较为恒定,颈、腰注射例在降核和内侧核的尾端尤为密集。