Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Telencephalon”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1989

Neo-Timm and selenium stainable glial cells of the rat telencephalon.

The Neo-Timm and selenium methods predominantly stain the neuropil of the rat brain and have been found to visualize zinc in synaptic vesicles. A fraction of glial cells and neuronal somata is also stained, especially when the Neo-Timm method is used. In the present study the localization and appearance of stained glial cells in the rat telencephalon are described using the two methods and the effect of metal chelating agents on the stained glial cells is examined. Neo-Timm stained glial cells were observed in both white and grey matter, with a preponderance in the major fiber tracts of the telencephalon, and were seen to contain rather large silver grains in their cytoplasm. Chelation with diethyldithiocarbamate (DEDTC) or dithizone prevented this staining. Brains from rats treated intravitally with selenium contained only occasionally stained glial cells. However, when present they showed the same characteristics as the Neo-Timm stained glial cells, including the reaction to chelation. Although both the Neo-Timm and selenium methods primarily visualize zinc in the neuropil of the rat brain, the possibility that copper could contribute to the glial cell staining cannot be ruled out. This possibility is further discussed.

Animals↗
PubMed1980

Cytology and time of origin of interstitial neurons in the white matter in infant and adult human and monkey telencephalon.

The fine structure, synaptic relationships, distribution and time of origin of interstitial neurons situated within the white matter subjacent to the visual, somatosensory and motor cortices were studied in the human and monkey telencephalon. The analysis was carried out on Nissl-stained serial sections, rapid Golgi impregnations, by acetylcholinesterase (AChE) histochemistry, electron microscopy and [3H]thymidine ([3H]TdR) autoradiography. Interstitial neurons have a similar distribution, morphology and histochemistry in both human and monkey telencephalon. Their highest density and the most extensive distribution is found in the neonatal period in both species. The number of interstitial neurons decreases during infancy, but numerous cells remain in the adult. Two types of interstitial neuron can be recognized in Golgi preparations: polymorphic cells, usually situated close to the cortex and fusiform cells, located predominantly in the depths of the white matter. The polymorphic cell type is prevalent during neonatal and infant stages, while fusiform cells are relatively more numerous in the adult. Interstitial cells have ultrastructural features and organelles typical of neurons of the central nervous system with well-defined axosomatic and axodendritic synapses of both symmetrical and asymmetrical types. About 20% fo the interstitial cells show strong specific AChE activity. Autoradiographic analysis of postnatal monkeys exposed to [3H]TdR at various embryonic (E) and early postnatal days indicates that interstitial neurons which lie beneath the visual and somatosensory-motor cortices are generated between E38 and E48. Contrary to the prevailing notion that interstitial neurons are the latest generated cells arreste during migration across the maturing white matter, they prove to be produced at the end of the first third of the 165-day gestation in the rhesus monkey concomitantly with the generation of neurons destined for the deep neocortical layers. These findings raise the possibility that interstitial cells represent a vestige of the transient embryonic subplate layer.

Acetylcholinesterase↗
PubMed1985

Neurotransmitter-related markers in the normal and experimentally lesioned telencephalon of the goldfish.

The telencephalon of teleost fish shows high affinity uptake for D-[3H]aspartate, intermediate levels of GABAergic markers and low levels of cholinergic enzymes. Experimental results (resection of the olfactory tracts or unilateral kainic acid administration in the telencephalon) suggest that: the projection from the olfactory bulbs to telencephalic targets is mediated by aspartate and/or glutamate; and a population of GABAergic neurons is present in a telencephalic area which is considered homologous to part of the striatal complex of land vertebrates. From the present results, it appears that the neurochemical approach can be used, in conjunction with neuroanatomical methods, to study evolutionary problems of telencephalic function.

Acetylcholinesterase↗
PubMed1985

An HRP study of afferent connections of the supracommissural ventral telencephalon and the medial preoptic area in himé salmon (landlocked red salmon, Oncorhynchus nerka).

The supracommissural ventral telencephalon and the medial preoptic area have been shown to play important roles in the sexual behavior of himé salmon (landlocked red salmon, Oncorhynchus nerka). In the present study, the sites of neurons projecting to these regions were examined by means of the retrograde horseradish peroxidase (HRP) tracing method. The morphology of neurons in these sites of origin was also studied by means of the Golgi method. The nucleus preopticus periventricularis and the rostral part of nucleus preopticus (NPP-rNPO) received bilateral projections from the middle parts of the area ventralis telencephali pars ventralis (Vv) and the area ventralis telencephali pars dorsalis (Vd), NPP and lateral part of the preoptic area (LPOA), ipsilateral projections from the caudal part of Vv, nucleus anterioris periventricularis (NAPv), nucleus ventromedialis thalami (NVM) at the level of the posterior commissure, nucleus lateralis tuberis pars medialis (NLTm), nucleus anterior tuberis (NAT), nucleus saccus vasculosus (NSV), nucleus recessus posterioris (NRP) and midbrain tegmentum (TG), and a projection from the nucleus posterior tuberis (NPT), which is situated on the midline of the brain. The area ventralis telencephali pars supracommissuralis and neighboring caudal ventral telencephalon (Vs-cV) received ipsilateral projections from almost all parts of the Vv, the middle and caudal parts of Vd, almost all parts of the NNP, the NPO at the level between the habenula and the posterior commissure, and the rostral part of the nucleus dorsomedialis thalami (NDM). The Vs-cV also received a projection from NPT. These findings seem to give anatomical bases for understanding the neural mechanisms involved in sexual behavior as well as neuroendocrine functions.

Afferent Pathways↗
PubMed1988

Thalamic nuclei that project to reptilian telencephalon lack GABA and GAD immunoreactive neurons and puncta.

Brains of reptiles, Caiman crocodilus, were processed by standard immunocytochemical methodology using a polyclonal antibody to gamma-aminobutyric acid (GABA) raised in rabbit and a polyclonal antibody to glutamic acid decarboxylase (GAD) raised in sheep. No GABA(+) or GAD(+) cells or puncta were observed over any thalamic nucleus known to project to the telencephalon in Caiman. These findings suggest that all thalamic nuclei that project to the telencephalon in Caiman lack intrinsic cells and presumably direct inhibitory input mediated by GABA.

Alligators and Crocodiles↗
PubMed1989

Retinal projection to mammalian telencephalon.

Retinal projections were studied in species from 8 orders of mammals using anterograde tracing techniques. The olfactory tubercle of basal telencephalon receives a projection from the retina in all animals. In all species the course of labelled fibers is similar and the terminal distribution of label along the internal border of the granular cell layer is restricted to the mediocaudal region of the tubercle. These shared characteristics suggest that this pathway is a typical mammalian feature, possibly providing for convergence of visual and chemosensory information in telencephalon.

Animals↗
PubMed1991

Reciprocal connections between the 'nucleus rotundus' and the dorsal lateral telencephalon in the weakly electric fish Gnathonemus petersii.

Injections of horseradish peroxidase into the dorsal lateral telencephalon of the weakly electric mormyrid fish Gnathonemus petersii resulted in retrogradely filled cells and anterogradely labelled terminals in the 'nucleus rotundus' of the ipsilateral rostral diencephalon. This connection courses via the lateral part of the lateral forebrain bundle. The present results suggest a particularly close relationship between the Dla cell group of the lateral telencephalon and the 'nucleus rotundus'.

Animals↗
PubMed1992

Mouse telencephalon exhibits an age-related decrease in glutamate (AMPA) receptors but no change in nerve terminal markers.

The central excitatory amino acid receptor selective for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) was examined in brain tissue from mice at 3 and 25 months after birth. Antibodies against the rat GluR-A glutamate receptor subunit (selective for kainate and AMPA) labeled a mouse brain component of about M(r) 100,000. Telencephalic tissue from the older group of mice exhibited 31% less immunoreactivity towards this component as compared with that from the young group. Binding of [3H]AMPA also decreased with age in the telencephalon to an extent which was similar to the loss of receptor immunoreactivity. Scatchard analysis revealed that this reduction is due to a decrease in receptor density and not to a change in binding affinity. In contrast, there were only small age-related changes in AMPA receptor immunoreactivity and binding levels in the brain stem and cerebellum. Binding to dopamine, serotonin, or GABA receptors was not significantly reduced in the older mice. Since the nerve terminal markers synaptophysin and the SV2 glycoprotein were not detectably different in the two groups of mice, the age-related reduction in AMPA receptors is not likely to be due to a general decrease in synaptic density. These data suggest that glutamatergic neurotransmission mediated by AMPA-type receptors is selectively impaired with aging in the telencephalon.

Aging↗
PubMed1995

Developmentally-regulated lectin binding in the embryonic mouse telencephalon.

Cell-surface carbohydrate epitopes are important determinants in cell-cell and cell-matrix interactions, and oligosaccharide groups are structural components of many growth factor receptors and cell adhesion molecules. These epitopes may participate in the regulation of stem cell proliferation and differentiation during central nervous system development. To further understand these cellular phenomena, it is important to define the changes in neuroepithelial cell-surface carbohydrate expression during development. We used a panel of fluorescein-conjugated lectins to label live, freshly dissociated cells from the embryonic day 11 to 18 (E11 to E18) mouse telencephalon. The intensity and heterogeneity of lectin labeling was assessed by flow cytometry. The lectins that we examined exhibited widely varying levels of labeling intensity. Lectins with the highest degree of binding included cholera toxin B subunit (CTB), which binds primarily to the gangliosides GM1 and GD1b, phaseolus vulgaris erythroagglutinating lectin (PHA-E), which binds to a variety of cell adhesion molecules, and wheat germ agglutinin (WGA). Many lectins showed increasing labeling intensity and cellular heterogeneity as development progressed. To determine if the observed cellular heterogeneity in lectin binding reflected biological differences in neuroepithelial cell subpopulations, cells from the E14 telencephalon were separated into two populations based on their intensity of CTB labeling using a fluorescence activated cell sorter. The population of weakly CTB labeled cells contained more than four times as many cells in S-phase of the cell cycle than the population of intensely CTB labeled cells. These observations suggest that lectin cytochemistry and flow cytometry can be useful in identifying specific cell subpopulations of neuroepithelial precursor cells during development, allowing their isolation and characterization in vitro.

Animals↗
PubMed1990

Changes in electric activity (EEG) of the telencephalon of conscious toads (Bufo paracnemis) caused by cholinergic stimulation of the mesencephalic tegmentum.

Studies were carried out to investigate the effect of microinjection of cholinergic agonist carbamylcholine (carbachol) into the mesencephalic tegmentum of conscious toads (Bufo paracnemis), subjected or not to section of the olfactory nerves, on the electrical activity (EEG) of the telencephalon. The response depended on the type of preexisting EEG activity. Marked desynchronization was observed both in animals with intact nerves and in animals with sectioned nerves, whose previous basal activity was already desynchronized (high frequency and low amplitude). In toads with synchronized basal activity and with intact nerves, an increase, a fall or even abolition of preexisting spindle-like activity occurred, whereas in animals with sectioned nerves the effect was reduction or abolition of spindle-like activity. The data show that stimulation of the mesencephalic tegmentum can alter the electrical activity of the telencephalon and that this effect is not only secondary to a change in nasal air flow alterations since it occurs in toads with sectioned olfactory nerves.

Animals↗
PubMed1995

Posthatching development of preproenkephalin mRNA-expressing cell populations in the pigeon telencephalon.

Enkephalin peptides are highly expressed in the vertebrate telencephalon. Our previous investigations in the pigeon and in the chicken [26] suggested that the cellular distribution of these peptides is conserved in phylogenetically 'old' telencephalic regions (e.g. the basal ganglia), while it has species-specific organizations in areas (e.g. dorsomedial forebrain and bulbus olfactorius) that are likely to play important roles in species-specific behaviors. In the present study, we investigated the posthatching development of preproenkephalin (PPE) mRNA-containing cells in the pigeon forebrain using in situ hybridization histochemistry. These cells are densely distributed in the paleostriatal complex (corresponding to the mammalian caudate-putamen) at hatching, and their density progressively decreases during the first 9 days posthatching, when it is similar to that of adult pigeons. In the dorsomedial forebrain (corresponding to the mammalian hippocampus), PPE mRNA-expressing cells are present at hatching, and their density reaches a peak around the 6th day posthatching. In the bulbus olfactorius, the first PPE mRNA-containing cells are observed after 9 days posthatching. The developmental profile of PPE mRNA expression in these areas of the pigeon telencephalon shows remarkable similarities with the development of enkephalinergic cells in corresponding brain areas of mammals. As in the mammalian caudate-putamen, the developmental expression of enkephalin peptides in the paleostriatal complex is likely to be related to neuronal withdrawal from the mitotic cycle. The developmental pattern of expression of PPE mRNA in the dorsomedial forebrain suggests that enkephalin peptides contribute to the maturation of the behavioral functions of this area.

Animals↗
PubMedDate not supplied

Avoidance learning in rats devoid of the telencephalon plus thalamus.

Two experiments were undertaken to investigate whether learning of an inhibitory avoidance response is possible in rats devoid of the whole forebrain, except for the hypothalamus. In experiment I all telencephalic structures were surgically ablated. Twenty-four hours later the rats were given a learning trial in the up-hill avoidance task. When tested 2 h later, the animals given a tail-shock contingent on the up-hill response showed significant increases in step-up latencies in comparison with control groups that had received non-contingent shock or no shock. In experiment II the thalamus was removed in addition to the telencephalon. As in experiment I, the animals received either tail-shock contingent on the up-hill reaction, no tail-shock, or non-contingent shock. When tested 2 and 24 h after the training, the animals that had received response-contingent shock showed significant increases in latencies to ascend the platform. These results indicate that inhibitory avoidance conditioning is still possible in rats devoid of the telencephalon plus thalamus.

Animals↗
PubMed1994

Differential subcellular localization of two populations of glutamate/AMPA receptors in the rat telencephalon.

The distribution of glutamate AMPA receptors in the synaptosomal and microsomal fractions of neonatal and adult rat telencephalon was studied by determining the saturation kinetics at equilibrium of 3H-AMPA and 3H-CNQX binding. At both ages, synaptosomal preparations exhibited two populations of 3H-AMPA binding sites with a small number of high affinity sites and a large number of low affinity sites. 3H-AMPA binding to microsomal preparations from both neonatal and adult rat telencephalon exhibited a much higher proportion of high affinity relative to low affinity sites. 3H-CNQX binding to the same fractions did not parallel 3H-AMPA binding, but was correlated with the low affinity 3H-AMPA binding and with a marker of plasma membranes. The results suggest that nonsynaptic glutamate/AMPA receptors have a high affinity for agonist and become low affinity when inserted into postsynaptic membranes and that 3H-CNQX binds synaptic but not nonsynaptic glutamate/AMPA receptors with high affinity.

Animals↗
PubMed1985

Cholinergic neurons in the telencephalon of the reptile Caiman crocodilus.

Choline acetyltransferase (ChAT) immunohistochemistry was used to characterize the distribution of cholinergic neurons in the telencephalon of the reptile, Caiman crocodilus. ChAT-positive cell bodies were observed within the small-celled portion of the ventrolateral area of the telencephalon (VLA s.c.), a region previously considered comparable to the mammalian caudate nucleus and putamen. A large field of cholinergic neurons was observed within the ventral paleostriatum (VP), a region comparable to the substantia innominata and ventral pallidum of mammals. Cholinergic neurons were also observed within cranial motor nuclei of the brainstem, within the isthmic nucleus and within portions of the lateral reticular formation of the pons and medulla. A rich plexus of cholinergic fibers was observed within the intermediate and deep layers of the optic tectum. The results of this study indicate that many aspects of cholinergic system organization are similar in caiman and mammals, and suggest a common derivation of these systems from ancestral forms.

Acetylcholinesterase↗
PubMed1989

Cell groups afferent to the telencephalon in a cartilaginous fish (Platyrhinoidis triseriata). A WGA-HRP study.

Cell groups projecting to the telencephalon in the guitarfish Platyrhinoidis triseriata were localized by retrograde transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) from injections into the basal forebrain bundle. Labeled neurons were observed bilaterally in the dorsal and ventral thalamus, hypothalamus, mesencephalon and rostral rhombencephalon. A comparison of the labeled cell groups to those which project to the telencephalon in terrestrial vertebrates reveals many parallels, including position in the brain, similarities in the afferent connections and immunoreactivity. Further data are needed to decide whether the cell groups in Platyrhinoidis are homologous or homoplasious to their counterparts in land vertebrates.

Animals↗
PubMed1992

Telencephalon-restricted expression of BF-1, a new member of the HNF-3/fork head gene family, in the developing rat brain.

We have previously characterized a novel transcription factor family in mammals, the HNF-3 family, by the members' homology to one another and to the Drosophila homeotic gene fork head. The expression of fork head is restricted to the anterior and posterior termini of the early fly embryo. Brain factor 1 (BF-1) is a new member of this family isolated from rat brain with an expression pattern and DNA binding specificity distinct from the HNF-3 genes. Expression is highly restricted in the developing neural tube to its rostral end, which gives rise to the telencephalon. These results suggest that BF-1 plays an important role in the establishment of the regional subdivision of the developing brain and in the development of the telencephalon.

Amino Acid Sequence↗
PubMed1995

Evidence that pioneer olfactory axons regulate telencephalon cell cycle kinetics to induce the formation of the olfactory bulb.

Early olfactory axons follow a specific pathway to reach the developing telencephalon. We observed that a subpopulation of these axons, the pioneer olfactory axons, penetrate into the ventricular zone of a highly restricted region of the telencephalon at E13 and E14. At E15, this same telencephalic region evaginates to form the olfactory bulb. To investigate the possibility that the pioneer olfactory axons induce the olfactory bulb by influencing precursor cell populations, we compared cell cycle kinetics and differentiation in the olfactory bulb primordium and the adjacent neocortex using cumulative bromdeoxyuridine labeling. The results showed that, 24 hr after the arrival of the first pioneer axons, the duration of the cell cycle is prolonged significantly in the olfactory bulb primordium. In addition, twice as many cells have exited the mitotic cycle in the olfactory bulb primordium versus the adjacent cortex. These findings suggest that pioneer olfactory axons play a role in the induction of the olfactory bulb by selectively modulating cell cycle kinetics in the olfactory bulb primordium. Afferent axons may influence target morphogenesis by modulating target precursor cell proliferation in other developing neural structures.

Animals↗
PubMed2006

Deficits in acquisition of spatial learning after dorsomedial telencephalon lesions in goldfish.

Acquisition of spatial learning is an important function of mammalian hippocampus. In order to identify the brain areas in teleost fish that are homologous to mammalian hippocampus, the present study examined the effects of lesions in the dorsal area of the caudal telencephalon of goldfish (Carassius auratus) on the acquisition of spatial learning. An open-field maze that was similar to the dry version of the Morris water maze was used. The task consisted of habituation and postoperative training to reach the position of the bait. Extramaze cues were visible in the habituation sessions in experiment 1, while they were blocked and not visible in the habituation sessions in experiment 2. Only in experiment 2, there was a significant deficit in the performance in the training sessions in the goldfish with damage to the dorsomedial area of the caudal telencephalon (DM). These data showed that blocking of the extramaze cues in the habituation sessions caused deficits in postoperative acquisition of spatial learning in the training sessions in the goldfish with DM lesions. Latent learning in the habituation sessions, however, eliminated the effects of the DM lesions on spatial learning. The present study suggests that the DM plays a critical role in acquisition of spatial learning.

Analysis of Variance↗