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At least 19 recordsLinked to original sources

PubMed2001

Expression of calbindin and calretinin in the human ganglionic eminence.

The conspicuous ganglionic eminence representing a part of the telencephalic proliferative zone contains neuroblasts of the striatum. Recently it has been found to contribute significantly to the class of interneurons in the cerebral cortex. Subpopulations of cortical interneurons contain calretinin and calbindin. The expression of calretinin and calbindin in the ganglionic eminence and adjacent areas has been investigated immunocytochemically during fetal development using the brains of 10 infants ranging in age from 16 and 26 weeks gestation. Between 16 and 20 weeks gestation, numerous calretinin-immunreactive nerve cells are found in the ganglionic eminence, particularly in the mantle and the intermediate zones. The number of calretinin-immunoreactive cells decreases gradually from 21 weeks gestation onwards. Larger calbindin-immunoreactive cells are seen in the ganglionic eminence, and their number increases from 20 weeks gestation in the mantle zone. These results may indicate that calretinin-immunoreactive precursor cells, found in the ganglionic eminence, tangentially migrate toward the cortex. Moreover, the mantle zone displaying a specific calretinin and calbindin immunolabeling may represent an intermediate target for outgrowing axons. The findings are discussed with regard to central nervous system complications in preterm infants involving the ganglionic eminence.

Calbindin 2↗

PubMed1998

Early specification of striatal projection neurons and interneuronal subtypes in the lateral and medial ganglionic eminence.

The striatum is thought to be generated from two transient swellings in the ventral telencephalon, the lateral and medial ganglionic eminences, present at mid-stages of embryonic rat development. We have studied the relative contribution of these structures to the specific generation of striatal neuronal subtypes such as projection neurons and cholinergic and somatostatin-containing interneurons at an early stage and a mid stage in striatal neurogenesis. Dissociated progenitors isolated from the embryonic day 12.5 and embryonic day 15.5 rat lateral ganglionic eminence grafted into the previously ibotenic acid lesioned adult striatum, produce grafts containing extensive numbers of neurons expressing messenger RNA for the striatal projection neuron marker, DARPP-32, whereas grafts of the embryonic day 12.5 and embryonic day 15.5 medial ganglionic eminences do not. While preprosomatostatin messenger RNA-expressing neurons were observed in grafts from each of the lateral ganglionic eminence and medial ganglionic eminence at both embryonic day 12.5 and embryonic day 15.5, choline acetyltransferase messenger RNA-expressing cholinergic neurons were largely found in grafts derived from the embryonic day 12.5 medial ganglionic eminence. These results suggest that the neuronal diversity of the adult striatum may derive both from the lateral ganglionic eminence, providing DARPP-32-expressing projection neurons as well as somatostatin-containing interneurons, and the early stage medial ganglionic eminence specifically contributing the cholinergic interneurons.

Animals↗

PubMed2002

The ganglionic eminence--a putative intermediate target of amygdaloid connections.

The superior part of the ganglionic eminence has been shown to act as an intermediate target for outgrowing axons of projections between the thalamus and the cerebral cortex. This study aims at investigating whether amygdaloid projections transiently contact the inferior portion of the human ganglionic eminence which directly borders upon the amygdala. Between 16 and 20 weeks of gestation a high number of small fiber bundles which were immunolabelled with anti-MAP1b and anti-SNAP-25 could be traced from the amygdala towards the mantle zone of the ganglionic eminence. These fiber bundles left a fiber system which coursed from the amygdala towards the entorhinal cortex. Within the mantle zone of the ganglionic eminence immunoreactive puncta indicative of fiber termination were observed. After 22 weeks of gestation the number of fibers entering the ganglionic eminence gradually decreased. These results provide the first evidence that the marginal zone of the inferior ganglionic eminence is likely to constitute an intermediate target for growing axons which belong the amygdaloid projection to the entorhinal cortex.

Amygdala↗

PubMed1995

Projection neurons in fetal striatal transplants are predominantly derived from the lateral ganglionic eminence.

In the present study, we have characterized aspects of integration, growth and phenotypic differentiation of embryonic grafts derived from the selective dissection of either the lateral or medial portion of the ganglionic eminences of the rodent forebrain. Donor tissues were derived from embryonic day 15 rat, or embryonic day 14 mouse embryos, and injected, as single cell suspensions into the striatum or substantia nigra of adult rats previously subjected to an intrastriatal ibotenic acid lesion. Two to six weeks following grafting, immunocytochemical detection of DARPP-32, the 32,000 mol. wt dopamine- and cyclic AMP-regulated phosphoprotein, was used to identify areas with a striatum-like phenotype within both the intrastriatal and the intranigral grafts. It was thus revealed that all the lateral ganglionic eminence grafts, irrespective of their placement, were dominated by striatum-like tissue (up to 90% of the total graft volume), while the medial ganglionic eminence transplants were only sparsely positive (< 10% of the total graft volume). These striatum-like regions of the grafts were selectively innervated by tyrosine hydroxylase immunopositive fibres from the host substantia nigra. Furthermore, axons derived from the lateral ganglionic eminence mouse grafts placed in the striatum, as detected by the mouse-specific neuronal marker M6, showed a more extensive and directed outgrowth towards the globus pallidus when compared to fibres emanating from the medial ganglionic eminence grafts. Mouse lateral and medial ganglionic eminence grafts placed into the substantia nigra exhibited similar fibre outgrowth patterns; both types of grafts thus innervated the substantia nigra-pars reticulata and extended axons into the cerebral peduncle. These results show that DARPP-32-positive striatal projection neurons are derived, for the most part, from the lateral ganglionic eminence and that the restricted lateral ganglionic eminence dissection provides a more optimal source of striatal tissue for grafting in the rat Huntington model.

Animals↗

PubMed1999

Retinoids are produced by glia in the lateral ganglionic eminence and regulate striatal neuron differentiation.

In order to identify molecular mechanisms involved in striatal development, we employed a subtraction cloning strategy to enrich for genes expressed in the lateral versus the medial ganglionic eminence. Using this approach, the homeobox gene Meis2 was found highly expressed in the lateral ganglionic eminence and developing striatum. Since Meis2 has recently been shown to be upregulated by retinoic acid in P19 EC cells (Oulad-Abdelghani, M., Chazaud, C., Bouillet, P., Sapin, V., Chambon, P. and Dollé, P. (1997) Dev. Dyn. 210, 173-183), we examined a potential role for retinoids in striatal development. Our results demonstrate that the lateral ganglionic eminence, unlike its medial counterpart or the adjacent cerebral cortex, is a localized source of retinoids. Interestingly, glia (likely radial glia) in the lateral ganglionic eminence appear to be a major source of retinoids. Thus, as lateral ganglionic eminence cells migrate along radial glial fibers into the developing striatum, retinoids from these glial cells could exert an effect on striatal neuron differentiation. Indeed, the treatment of lateral ganglionic eminence cells with retinoic acid or agonists for the retinoic acid receptors or retinoid X receptors, specifically enhances their striatal neuron characteristics. These findings, therefore, strongly support the notion that local retinoid signalling within the lateral ganglionic eminence regulates striatal neuron differentiation.

Animals↗

PubMed1996

Phenotypic development of the human embryonic striatal primordium: a study of cultured and grafted neurons from the lateral and medial ganglionic eminences.

Basic parameters which are crucial for the survival of human embryonic striatal grafts need to be investigated before initiating clinical trials in Huntington's disease. In order to define the dissection of human striatal-donor tissue which gives rise to the largest amount of striatal neurons after intrastriatal transplantation, we studied the lateral and medial ganglionic eminences of embryonic striatal primordia obtained from human embryos sized 17-30 mm in crown-to-rump length (corresponding to Carnegie stages 18-23). Anatomical landmarks that demarcated the lateral and medial ganglionic eminences from each other were present only in embryos with 20 mm crown-to-rump length or larger. In monolayer cultures, the lateral ganglionic eminence gave rise to a six-fold higher yield of dopamine- and cyclic AMP-regulated phosphoprotein 32-immunoreactive striatal neurons as compared to the medial ganglionic eminence. We also xenografted the lateral and medial ganglionic eminences from five embryos sized 21-30 mm in crown-to-rump length to the ibotenate lesioned striatum of immunosuppressed rats. The grafts were evaluated with respect to general morphology, survival and integration using (immuno-) histochemical stains for acetylcholinesterase/Cresyl Violet, nicotinamide adenine dinucleotide phosphate-diaphorase, dopamine- and cyclic AMP-regulated phosphoprotein-32, tyrosine hydroxylase and calbindin-D28KD. As assessed 9-25 weeks after implantation, 13 out of 16 and 8 out of 13 grafts, in the groups grafted with the medial and lateral ganglionic eminences, respectively, had survived. Previous studies with rat donor tissue have indicated that the functional efficacy of striatal grafts is related to the development of striatal-specific P-zone regions and that these are enriched in transplants derived from the lateral as opposed to the medial ganglionic eminence. Also in the human striatal xenografts of the present study, P-zones appeared more abundant when the donor tissue was derived from the lateral ganglionic eminence. However, the proportion of graft tissue that expressed P-zone properties was always very low (at most 30%) and never approached the 80-90% previously observed in transplants of rat lateral ganglionic eminence. We conclude that the relative yield of striatal neurons in grafts of the human embryonic striatal primordium has to be improved before neural transplantation should be applied in patients with Huntington's disease.

Acetylcholinesterase↗

PubMed2000

Transient structures of the human fetal brain: subplate, thalamic reticular complex, ganglionic eminence.

Morphological features of the subplate, the thalamic reticular complex and the ganglionic eminence, which represent three major transient structures of the human fetal forebrain, are summarized with special reference to their functional roles. The subplate harboring various neuronal types is an outstandingly wide zone subjacent to the cortical plate in the human fetal brain. Within the subplate various cortical afferents establish synaptic contacts for a prolonged period before entering the cortical plate. Therefore, the subplate is regarded as a "waiting compartment" which is required for the formation of mature cortical connections. Next to the thalamic reticular nucleus, within the fibers of internal capsule, the perireticular nucleus is located which has been established as a distinct entity during development. Its various neuronal types express a number of different neuroactive substances. Perinatally, the perireticular nucleus is drastically reduced in size. It is involved in the guidance of corticofugal and thalamocortical fibers. The ganglionic eminence is a conspicuous proliferative area that persists throughout nearly the entire fetal period. In the human fetal brain it extends medially upon the dorsal thalamic nuclei which receive precursor cells from the ganglionic eminence. Postmitotic cells in the marginal zone of the ganglionic eminence serve as an intermediate target for growing axons. On the whole, all three structures establish transient neural circuitries that may be essential for the formation of adult projections. The characteristics of the three transient structures are particularly relevant for developmental neuropathology as these structures may be damaged in disorders that preferentially occur in preterm infants.

Animals↗

PubMed1990

[Stereological analysis of the vascular network of the ganglionic eminence and the corpus striatum during brain development in man].

A study of the volume density of the ganglionic eminence vascular network and the constituent parts of the corpus striatum was performed on 8 chosen foetal brains, which were well-injected with a mixture of India ink and gelatin, aged from 14-25 postovulatory weeks. The volume density of the ganglionic eminence vascular network amounts to 0.0209-0.0300 mm0, of the caudate nucleus to 0.0131-0.0181 mm0, of the putamen to 0.0136-0.0159 mm0, and of the globus pallidus to 0.0121-0.0159 mm0. The comparison of the results obtained, shows that the volume density of the ganglionic eminence vascular network is higher than the volume density of the other examined structures and that this difference is statistically highly significant (p less than 0.01). The augmented volume density of the ganglionic eminence vascular network points to a possibility of slow blood flow through its vascular bed, which was experimentally demonstrated on animals. This slow blood flow, among other factors, may be the cause of a ganglionic eminence venous infarction in premature newborns of low birthweight.

Corpus Striatum↗

PubMedDate not supplied

Addition of lateral ganglionic eminence to rat mesencephalic grafts affects fiber outgrowth but does not enhance function.

Addition of embryonic striatal tissue, usually as a combination of the lateral and medial ganglionic eminences, to intrastriatal mesencephalic grafts has previously been reported to enhance recovery of drug-induced rotational behavior in the host and to modify axonal fiber outgrowth from the grafted dopaminergic neurons. This study investigated the effects of adding (cografting) either lateral or medial ganglionic eminence tissue to embryonic mesencephalic grafts implanted intrastriatally, in rats with unilateral 6-hydroxydopamine lesions. The cografts did not exhibit increased survival or cell size of dopaminergic neurons when compared to transplants of mesencephalic tissue alone. Neither did recipients of cografts exhibit any enhancement of graft-induced recovery of function, when tested for drug-induced rotational behavior or forelimb function in the staircase test. However, cografts containing lateral ganglionic eminence displayed patches of dense tyrosine hydroxylase-immunoreactive fibers within the graft tissue. These patches largely coincided with patches in adjacent stained sections, which were rich in immunostaining for the striatal-specific marker dopamine- and cyclic AMP-regulated phosphoprotein-32 (DARPP-32). Such patches were not present in rats receiving cografts containing medial ganglionic eminence or mesencephalic tissue alone. Thus, it seems that the grafted dopaminergic neurons preferentially grow into the areas of the transplants containing lateral ganglionic eminence tissue. In summary, the results suggest that embryonic lateral ganglionic eminence exerts trophic effects on the outgrowth of dopaminergic axons, but does not enhance the behavioral effects of grafted dopaminergic neurons.

Animals↗

PubMed2004

Expression of connexin 26 in the ganglionic eminence of preterm infants after bleedings.

The ganglionic eminence being a prominent part of the telencephalic proliferative zone is the most common site of bleedings in preterm infants. This immunohistochemical study demonstrates that connexin 26 involved in forming intercellular gap junctions is expressed in ganglionic eminence cells up to 500 microm from the bleeding. In controls, no positive cells are present. It is discussed that an increase of gap junctional communication may result in spreading of the primary injury.

Brain Ischemia↗

PubMed1996

Dynamics of cell migration from the lateral ganglionic eminence in the rat.

From previous developmental studies, it has been proposed that the neurons of the ventrolateral cortex, including the primary olfactory cortex, differentiate from progenitor cells in the lateral ganglionic eminence. The objective of the present study was to test this hypothesis. The cells first generated in the forebrain of the rat migrate to the surface of the telencephalic vesicle by embryonic day (E) 12. Using [3H]thymidine, we found that most of these cells contributed to the formation of the deep layer III of the primary olfactory cortex. To study the migratory routes of these cells, we made localized injections of the carbocyanine fluorescent tracers Dil and DiA into various parts of the lateral ganglionic eminence in living embryos at E12-E14 and subsequently maintained the embryos in a culture device for 17-48 hr. After fixation, most migrating cells were located at the surface of the telencephalic vesicle, whereas others were seen coursing tangentially into the preplate. Injections made at E13 and in fixed tissue at E15 showed that migrating cells follow radial glial fibers extending from the ventricular zone of the lateral ganglionic eminence to the ventrolateral surface of the telencephalic vesicle. The spatial distribution of radial glial fibers was studied in Golgi preparations, and these observations provided further evidence of the existence of long glial fibers extending from the ventricular zone of the lateral ganglionic eminence to the ventrolateral cortex. We conclude that cells of the primary olfactory cortex derive from the lateral ganglionic eminence and that some early generated cells migrating from the lateral ganglionic eminence transgress the cortico-striatal boundary entering the preplate of the neocortical primordium.

Animals↗

PubMed1999

Cell migration from the ganglionic eminence to the neocortex investigated by labeling nuclei with UV irradiation via a fiber-optic cable.

Recent studies have shown that the ganglionic eminence is one of the sources of tangentially migrating cells in the developing neocortex. Since the migration of the DiI-labeled cells from the ganglionic eminence to the neocortex was not monitored by videomicroscopy in these reports, we devised a novel method to study cell migration in vitro and in vivo. The new method involves ultraviolet (UV) irradiation of the cells through a fiber-optic cable and subsequent identification of the irradiated cells on the basis of the formation of thymine dimers in the nuclei. First, we tested the new method (UV-thymine dimer-labeling method) by applying it to monitor the cell migration of neuronal precursor cells in the rostral migratory stream in the neonatal rat telencephalon. In vitro, UV irradiation for 1 s through the fiber-optic cable resulted in the formation of sufficient thymine dimers as to allow immunohistochemical detection after 6 h of incubation; a significant proportion of the irradiated cells continued to migrate in the same direction and at the same speed as those before irradiation. There was no significant difference in the cell migration distance over 6 h between cells exposed and not exposed to the UV irradiation in vitro. In vivo, this method revealed that three times as many cells in the subventricular zone of the olfactory bulb migrated rostrally as caudally. The new method also allowed us to measure the speed of cell migration, which was estimated to be about 70 microm/h at the maximum in the rostral direction. After these examinations of reliability of the method, we applied it to the rat embryo brain. One day after UV irradiation of the ganglionic eminence, labeled migrating cells were found in the striatum, in the internal capsule, and in the intermediate zone of the neocortex. The observation period of cell migration to the neocortex was extended by the use of a xeroderma pigmentosum group A gene mutant mouse, which lacked an ability to remove thymine dimer from the UV-irradiated nuclei. Two days after the UV irradiation, labeled migrating cells from the ganglionic eminence of the mutant mouse embryos were found both in the cortical plate and in the intermediate zone of the neocortex.

Animals↗

PubMed2001

Expression of leukemia inhibitory factor in the ganglionic eminence of the human fetal brain after bleedings.

Bleedings in the ganglionic eminence (GE) being a prominent domain of the telencephalic proliferative zone is a frequent complication of preterm infants. Such bleedings may induce cellular responses in the vicinity of the lesion. Using immunohistochemistry, this study demonstrates for the first time that leukemia inhibitory factor (LIF) belonging to the family of neuropoetic cytokines is expressed in GE cells up to 200 microm from the lesion (six brains, gestational age 22-26 weeks); whereas control brains do not exhibit any LIF-immunoreactive cells in the GE. The expression of LIF in cases with bleedings may interfere with normal developmental processes taking place within the ganglionic eminence.

Astrocytes↗

PubMed2004

Cocaine exposure decreases GABA neuron migration from the ganglionic eminence to the cerebral cortex in embryonic mice.

Recurrent exposure of the developing fetus to cocaine produces persistent alterations in structure and function of the cerebral cortex. Neurons of the cerebral cortex are derived from two sources: projection neurons from the neuroepithelium of the dorsal pallium and interneurons from the ganglionic eminence of the basal telencephalon. The interneurons are GABAergic and reach the cerebral cortex via a tangential migratory pathway. We found that recurrent, transplacental exposure of mouse embryos to cocaine from embryonic day 8 to 15 decreases tangential neuronal migration and results in deficits in GABAergic neuronal populations in the embryonic cerebral wall. GABAergic neurons of the olfactory bulb, which are derived from the ganglionic eminence via the rostral migratory pathway, are not affected by the cocaine exposure suggesting a degree of specificity in the effects of cocaine on neuronal migration. Thus, one mechanism by which prenatal cocaine exposure exerts deleterious effects on cerebral cortical development may be by decreasing GABAergic neuronal migration from the ganglionic eminence to the cerebral wall. The decreased GABA neuron migration may contribute to persistent structural and functional deficits observed in the exposed offspring.

Animals↗

PubMed2002

Absence of Cajal-Retzius cells and subplate neurons associated with defects of tangential cell migration from ganglionic eminence in Emx1/2 double mutant cerebral cortex.

Emx1 and Emx2, mouse orthologs of the Drosophila head gap gene, ems, are expressed during corticogenesis. Emx2 null mutants exhibit mild defects in cortical lamination. Segregation of differentiating neurons from proliferative cells is normal for the most part, however, reelin-positive Cajal-Retzius cells are lost by the late embryonic period. Additionally, late-born cortical plate neurons display abnormal position. These types of lamination defects are subtle in the Emx1 mutant cortex. In the present study we show that Emx1 and Emx2 double mutant neocortex is much more severely affected. Thickness of the cerebral wall was diminished with the decrease in cell number. Bromodeoxyuridine uptake in the germinal zone was nearly normal; moreover, no apparent increase in cell death or tetraploid cell number was observed. However, tangential migration of cells from the ganglionic eminence into the neocortex was greatly inhibited. The wild-type ganglionic eminence cells transplanted into Emx1/2-double mutant telencephalon did not move to the cortex. MAP2-positive neuronal bodies and RC2-positive radial glial cells emerged normally, but the laminar structure subsequently formed was completely abnormal. Furthermore, both corticofugal and corticopetal fibers were predominantly absent in the cortex. Most importantly, neither Cajal-Retzius cells nor subplate neurons were found throughout E11.5-E18.5. Thus, this investigation suggests that laminar organization in the cortex or the production of Cajal-Retzius cells and subplate neurons is interrelated to the tangential movement of cells from the ganglionic eminence under the control of Emx1 and Emx2.

Animals↗

PubMed2000

Transient expression of synaptogyrin in the ganglionic eminence of the human fetal brain.

The ganglionic eminence (GE) representing a conspicuous bulb-like elevation of the telencephalic proliferative zone has recently been shown to be involved in the establishment of cortical connections. This study demonstrates the presence of synaptogyrin-immunoreactivity in a large number of cell bodies of the human GE between 12 and 20 weeks of gestation. From the 20th week onwards synaptogyrin expression sharply declines. No immunoreactive structures are detectable in the 23rd week or later. As the GE persists nearly throughout the entire fetal period these results show that its neurochemical features change distinctly in the course of development. The synaptogyrin-immunoreactive GE-cells may form an early corticopedal connection which provides a scaffold for outgrowing cortical axons.

Abortion, Induced↗

PubMed2005

Ambient GABA promotes cortical entry of tangentially migrating cells derived from the medial ganglionic eminence.

During corticogenesis, cells from the medial ganglionic eminence (MGE) migrate tangentially into the neocortical anlage. Here we report that gamma-aminobutyric acid (GABA), via GABAA receptors, regulates tangential migration. In embryonic telencephalic slices, bicuculline produced an outward current in migrating MGE-derived cells in the neocortex, suggesting the presence of and tonic activation by ambient GABA. Ambient GABA was also present in the MGE, although this required demonstration using as bioassay HEK293 cells expressing high-affinity alpha6/beta2/gamma2s recombinant GABAA receptors. The concentration of ambient GABA was 0.5+/-0.1 microM in both regions. MGE-derived cells before the corticostriate juncture (CSJ) were less responsive to GABA than those in the neocortex, and profiling of GABAA receptor subunit transcripts revealed different expression patterns in the MGE vis-à-vis the neocortex. These findings suggest a dynamic expression of GABAA receptor number or isoform as MGE-derived cells enter the neocortex and become tonically influenced by ambient GABA. Treatment with bicuculline or antibody against GABA did not affect migration of MGE-derived cells before the CSJ but decreased "crossing index," reflecting impeded migration past the CSJ into the neocortex. Treatment with diazepam or addition of exogenous GABA increased crossing index. We conclude that ambient GABA promotes cortical entry of tangentially migrating MGE-derived cells.

Animals↗

PubMed1999

Young neurons from medial ganglionic eminence disperse in adult and embryonic brain.

In this study, we identified neuronal precursors that can disperse through adult mammalian brain tissue. Transplanted neuronal precursors from embryonic medial ganglionic eminence (MGE), but not from lateral ganglionic eminence (LGE) or neocortex, dispersed and differentiated into neurons in multiple adult brain regions. In contrast, only LGE cells were able to migrate efficiently from the adult subventricular zone to the olfactory bulb. In embryonic brain slices, MGE cells migrated extensively toward cortex. Our results demonstrate that cells in different germinal regions have unique migratory potentials, and that adult mammalian brain can support widespread dispersion of specific populations of neuronal precursors. These findings could be useful in repair of diffuse brain damage.

Animals↗