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At least 19 recordsLinked to original sources

PubMed1977

[The activities of the transmitter metabolizing enzymes monoamineoxidase and acetylcholinesterase and of succinic dehydrogenase were investigated in the telencephalon of Salmo irideus (teleostei) (author's transl)].

The activities of the transmitter metabolizing enzymes monoamineoxidase and acetylcholinesterase and of succinic dehydrogenase were investigated in the telencephalon of Salmo irideus (teleostei). There is a high reaction intensity of the MAO in the whole telencephalon with graded differences between the various nuclear areas. It is highest in the area dorsalis telencephali; the larger fiber tracts (Tr. olfactorius medialis et lateralis; medial and lateral forebrain bundle) are strong MAO-positive, too. There is an extremely weak AchE-reaction throughout the telencephalon. The only nuclear area which is clearly histochemically demonstrable is the regio Dm2 in the area dorsalis telencephali. The SDH-activity is demonstrable in the whole telencephalon. The activity is higher in the area dorsalis as compared with the area ventralis telencephali. In the ependym there are only a few traces of MAO- and SDH-reaction products. The recent findings may support, from a histochemical view, the hypothesis that the telencephalon of Salmo irideus represents brain structures which show structural and functional similarities with limbic telencephalic structures of higher vertebrates.

Acetylcholinesterase↗

PubMed1978

Neuronal migration and contact guidance in the primate telencephalon.

Over the last decade, evidence from experimental studies on neuronal migration in non-human primates has accumulated to the point where it can significantly amplify our understanding of the normal and pathological development of the human telencephalon. Systematic analysis of neuron genesis by the method of H3-thymidine autoradiography shows that in rhesus monkeys all neurons destined for the neocortex are generated near the surface of the lateral ventricle during a two-month period in the middle of gestation. Following their last cell division, young neurons migrate outwards across the cerebral wall to the developing cortical mantle, a journey that requires one to three days at early stages of neurogenesis, or more than two weeks towards the end of cortical development. From the very beginning, the basic columnar organization of the neuroepithelium favours radial migration. During later stages, when the primate telencephalic wall expands unevenly in thickness and surface area and begins to form primary fissures and cerebral promontoria, young neurons migrate to their cortical destinations in apposition to fascicles of radial glial fibres which span the full distance between the ventricular and pial surface. Furthermore, it appears that several generations of neurons all originate in the same restricted location at the ventricular surface, migrate along the same glial fascicles and consequently accumulate in the same radial cortical 'columns' in which, as a rule, somas of later generated neurons take positions external to the somas of their predecessors. It is proposed that fascicles of radial fibres (a) facilitate neuronal migration to the distant cortical plate through a complex assembly of closely-packed cells and processes that compose the developing primate telencephalon; (b) provide constraints which preserve a radial alignment of clonally related neurons in cortical columns; and (c) reproduce the mosaicism of the germinal ventricular zone at the expanded and curved cerebral surface.

Animals↗

PubMed1977

Formaldehyde-induced fluorescence in the telencephalon and diencephalon of the eel (Anguilla anguilla l.). A fluorescence-microscopic and microspectrofluorometric investigation with special reference to the innervation of the pituitary.

In the telencephalon and diencephalon of the eel (Anguilla anguilla L.) formaldehyde-induced fluorescence was studied microscopically and microfluorometrically with special emphasis on the innervation of the pituitary. In the telencephalon fluorescent fibers contained predominantly noradrenaline fluorophores. Fluorescent nuclei could not be established. In the diencephalon fluorescent perikarya were found in: (1) the paraventricular organ (PVO), possessing either dopamine or, to a lesser extent, serotonin fluorophores; (2) the PVO-accompanying group, exhibiting spectral data resembling those of noradrenaline fluorophores; (3) the nucleus hypothalami anterior (NHA), a small paired group of catecholamine-containing cells posterior to the commissura transversa.--The nucleus lobi inferioris exhibited a high density of delicate, most probably dopamine-containing terminals, while fibers surrounding this nucleus contained noradrenaline fluorophores. A high density of fluorescent terminals containing dopamine and/or noradrenaline was found in the habenular complex. Fluorescent terminals in the pituitary contained fluorophores resembling either dopamine or noradrenaline. Fluorescent tracts entered the pituitary from different directions. A rostral, unpaired tract enters the neurointermediate lobe, as also verified experimentally. The rostral pars distalis receives two paired tracts, one from a rostral and one from a dorsal direction. The proximal pars distalis also receives two paired tracts, one from a dorsal and one from a posterior direction.

Anguilla↗

PubMed1975

Ascending afferents to the telencephalon of ranid frogs: an anterograde degeneration study.

Sources of telencephalic afferents were examined in two species of frogs, Rana catesbeiana and Rana pipiens, by study of anterograde degeneration resulting from hemisection of the brain at the isthmus or at the caudal border of the thalamus and from electrolytic lesions in various portions of the diencephalon. The results indicate that some telencephalic afferents arise from levels caudal to the isthmus, that some striatal afferents arise from a level between the isthmus and the caudal border of the thalamus, and that a projection to the ipsilateral striatum arises from the anterior and/or middle portions of the dorsal thalamus. Diencephalic projections to pallial portions of the hemisphere were also observed. These results demonstrate substantial non-olfactory afferent projections to the telencephalon in ranid frogs.

Animals↗

PubMed1979

An aberrant nucleus in the telencephalon following administration of ENU during neuroembryogenesis.

Administration of ENU to rats during embryonic development caused the emergence of aberrant nuclei in the dorsal telencephalon. They were located in the corpus callosum, and were composed of pyramidal and stellate neurons. This suggested that the aberrant nuclei arose out of the neurons of cerebral cortex that had failed to migrate during embryogenesis. The aberrant nuclei were found predominantly in the animals receiving ENU on day 18 or earlier of gestation.

Animals↗

PubMed1975

The monoaminergic innervation of the telencephalon of the frog, Rana pipiens.

A large number of serotonin (5-hydroxytryptamine, 5-HT)-type axon terminals has been visualized in the so-called 'striatum' (pars ventralis and dorsalis) of Rana pipiens by means of the Falck-Hillarp histochemical method. The frog striatum contains, however, a much smaller number of catecholamine (CA) type axon terminals and differs strikingly in that aspect from the neostriatum of 'higher' vertebrates which is known to receive a massive CA innervation. In the telencephalon of Rana pipiens the highest density of CA axon terminals occurs at the level of the medial wall, which appears highly hypertrophied in comparison to the thin lateral wall. The CA terminals are mainly concentrated within nucleus accumbens septi and in the ventrolateral portion of nucleus lateralis septi where they surround intimately the non-fluorescent neuronal somata of both septal nuclei. The three pallial fields (medial, dorsal and lateral) of Rana pipiens are nearly devoid of CA axon terminals. A moderate amount of 5-HT terminals is present, however, within the caudal half of both the medial and dorsal pallial fields. Finally, a few CA-type neuronal somata are found lying amongst the mitral cells of the olfactory bulb. As a whole, the telecenphalon of Rana pipiens appears more profusely innervated by axons of the 5-HT-type than by those of the CA-type. This finding has been related to the fact that in the frog brain stem the CA neuronal somata are scarce in comparison to the highly developed 5-HT neuronal systems.

Animals↗

PubMed1977

Subcellular distribution of cytochrome c oxidase, monoamine oxidase and lactate dehydrogenase in the developing chick telencephalon.

The distribution of cytochrome c oxidase monoamine oxidase and lactate dehydrogenase, together with protein, after isopycnic centrifugation of a crude mitochondrial fraction of chick telencephalon homogenate in a linear sucrose density gradient, was followed during late embryogenesis and postnatal maturation. Two main populations of subcellular organelles differentiate; they were characterized biochemically and analyzed by electron microscopy. One population, with a progressively defined mean buoyant density of 1.170 g/ml, exhibited a high relative activity of monoamine oxidase, with a low and relatively constant cytochrome c oxidase/monoamine oxidase activity ratio. This population was composed of free mitochondria and mitochondria enclosed in nerve endings, and possibly of mitochondria of perikaryal and glial origin. A second population, with a progressively well defined mean buoyant density of 1.182-1.186 g/ml, exhibited a high relative activity of cytochrome c oxidase, with a high and increasing cytochrome c oxidase/monoamine oxidase activity ratio. The biochemical and functional significance of these results were discussed.

Animals↗

PubMed1977

Autoradiographic localization of opiate receptors in rat brain. III. The telencephalon.

Opiate receptor distribution, determined by the autoradiographic localization of stereospecific [3H]diprenorphine binding sites, was examined in the telencephalon. Areas showing very dense or dense localization of receptors included parts of the presubiculum and amygdala, patchy areas in the caudate-putamen and accumbens, the subfornical organ, the interstriatal nucleus of the striae terminalis and the anterior olfactory nucleus, pars externa. Lower densities were found in other parts of the hippocampal formation, the deeper part of the cerebral cortex, the entopeduncular nucleus, globus pallidus, nucleus triangularis septi and nucleus paratenialis. The significance of these findings is discussed in terms of the biochemical and physiological actions of opiates.

Amygdala↗

PubMed1976

Endotoxin leucoencephalopathy in the telencephalon of the newborn kitten.

Prolonged exposure of the neonatal kitten to a lipopolysaccharide results in a telencephalic leucoencephalopathy characterized by astrogliosis and necrosis. The visceral organs of neonatal kittens and the telencephalon of mature cats are relatively resistent to the adverse effects of this lipopolysaccharide.

Age Factors↗

PubMed1976

Telencephalon of the lizard Gekko gecko (Linnaeus): some connections of the cortex and dorsal ventricular ridge.

Interhemispheric connections of the telencephalon in the lizard, Gekko, were studied with anterograde degeneration methods following lesions variously placed in the medial, dorsal, and lateral cortices and/or the dorsal ventricular ridge (D.V.R.). After lesions involving dorsal cortex, the medial wall, and the DVR, the majority of degenerated fibers decussate in the hippocampal commissure and terminate in the septum, medial wall, dorsal cortex, and the lateral edge of the DVR contralaterally. Lesions confined to dorsal cortex result in a similar pattern of degeneration, while lesions confined to the lateral wall result in degeneration in the contralateral lateral cortex, DVR and striatum, mainly via the anterior commissure. Some variation has been reported on the pattern of interhemispheric projections among reptiles studied to date; two possible interpretations of the data are that (1) dorsal cortex may be homologous as a field to parts of both neocortex and the hippocampal formation of mammals or (2) only the lateral part of dorsal cortex may be homologous to neocortex.

Animals↗

PubMed1975

[Chronoarchitectonic analysis of the rat brain using radioautography. I. Histogenesis of the telencephalon].

1) Isocortex We find a centrifugal type chronoarchitectonic gradient with, however, a considerable overlap between the various generations of neurons. Thus in the older, deep layers (13.5 days) of the lateral neocortex 35% of the cells are chromologically incongruous (certain are very recent: 17.5 days and more). Cell production is a continuous process and has its peak towards 15.5 days of gestation. This refutes the existence of successive waves of cells. It is not possible to give even an approximate date to the isocortical layers, for the cortical laminations and the isochrones are nor concentric. What finally characterizes this structure from a chronoarchitectonic point of view is the considerable duration of the sequence of neuron production going from 13,5 days to birth. 2) Allocortex We find a centrifugal gradient in the paleocortex. In several of the structures of which it is composed a chronoarchitectonic incongruity can be attributed to the microneurons. It is the case with the islands of CALLEJA (in the olfactive tubercule) which separate very late on. In the archicortex the dominant gradient is again centrifugal. Here we find horizontal variations of the chronoarchitectonic patterns which are discussed with reference to the conception of a possibly fragmented cortex. 3) Striatum the chronoarchitectonic results largely confirm the diencephalic origin of the paleostriatum (STRASSER 1920, SPATZ 1921). In the archistriatum we find a steep rostrocaudal gradient, while the chronoarchitectonic heterogeneity of the structure tends to confirm the conception of a mixed origin (striatum and paleopallium). 4) Claustrum there is a real chronoarchitectonic incongruity between this structure and the isocortex. On one hand the sequence of the anterior part of the claustrum is of the paleostriate type. The posterior part is more probably archistriate. These findings suggest that the formation of the claustrum is of hybrid origin. 5) Septum The characteristic gradient of this formation is caudorostral. This gradient is practically common to all the structures except the telencephalon. We also find a centrifugal gradient related to the presence of a recent "cortex" which could be the counterpart of the cortical septal nuclei in superior mammals.

Amygdala↗

PubMed1975

[Development of the telencephalon of Salmo irideus Gib].

A developmental study of the Telencephalon of the trout (Salmo irideus) has been done. The stages of fixation were 18 days after fecondation, hatching; 5 days, 1, 2, and 3 months, and 1 year after hatching. The different cell-masses are summarized in table 1. In the young trout, eversion is not important. Just, 2 olfactory bulbs are evaginated. In front of the commissura anterior, we can see: the Nucleus ventroventralis and the Nucleus ventrodorsalis, on the one hand; a voluminous dorsal area which includes: the Nucleus dorsolateralis, the Nucleus dorsomedialis, the Nucleus dorsocentralis and the dorso and ventro-lateral groups, on the other hand. The different Nuclei of the dorsal area are differentiated from a primordial territory which is the area intermedius at the hatching stage. On the hemispheric wall at the level of the tela, we can see the Nucleus teniae. Behind the plan of the commissura anterior, the Nucleus posterior is already seeing at the end of the first month after the hatching. A Golgi-Cox study showed some aspects of different kinds of neurons, and an important neuropil at the level of the Nucleus dorsocentralis too.

Animals↗

PubMed1975

The telencephalon of the sea catfish Galeichthys felis.

The sea catfish is a relatively abundant teleost fish. Its placement on the phylogenetic scale remains in question, although its brain resembles grossly those of some of the other teleosts which also possess pedunculated olfactory bulbs. The forebrain of Galeichthys felis consists of two hemispheres which lack lateral ventricles. They are joined at the midline by a thin membrane ventromedially and by the hippocampal and anterior commissures. The telencephalic hemispheres are overlaid by a single, ventrolaterally attached membrane which is continuous rostrally with the roofs of the olfactory ventricles. Six basic nuclear regions are evident in the telencephalon of the sea catfish: a dorsomedial, a ventromedial, a ventral, a lateral, a dorsal and a central. Dorsomedially, the primordial hippocampal formation is divided into an anterior continuation, a primordial dentate gyrus, a primordial cornu ammonis and a primordial subiculum. Ventromedially, the precommissural septum consists of the medial septal nucleus (pars dorsalis and pars ventralis), the lateral septal nucleus and the nuclei of the hippocampal and anterior commissure. Ventrally, the medial and the lateral zones and the medial island constitute the tuberculum olfactorium. The primordial general pallium comprises the dorsal area. Laterally, the primordial piriform cortex and the prepiriform region overlie the relatively large primordial amygdaloid complex, which includes an anterior anygdaloid nucleus, a primordial corticomedial amygdaloid nucleus and a primordial basolateral amygdaloid nucleus. The hyperstriatum, the neostriatum, and paleostriatum augmentatum and the paleostriatum primitivum constitute the central region. Basic fiber systems in Galeichthys felis which are homologous to those of higher vertebrates include the medial and the lateral olfactory tracts, the fornix, the medial and the lateral forebrain bundles, the stria medullaris pathways and the stria terminalis. In spite of the lack of lateral telencephalic ventricles in this form, nuclear areas were defined which, on the basis of topography, cellular morphology and fiber pathways, were homologized with the six basic regions found in the forebrain of higher vertebrates. The basic pattern of the fiber pathways present in the sea catfish corresponds to that found in the other submammalian vertebrates.

Amygdala↗

PubMed1977

Immunohistochemical studies on the localization and distribution of monoamine neuron systems in the rat brain II. Tyrosine hydroxylase in the telencephalon.

Extensive plexuses of TH-positive nerve terminals were found in many parts of the telencephalon, mainly confined to the subcortical and limbic cortical structures. Of special interest were the distinct networks of varying densities in the amygdaloid cortex, the entorhinal cortex, the prepiriform cortex, the anterior cingulate cortex and the (pre-)frontal cortex. Their distribution is identical with the patterns observed in recent studies on cortical dopamine nerve terminals using certain modifications of the Falck-Hillarp technique. The extremely dense TH innervations patterns of the caudate nucleus, nucleus accumbens, tuberculum olfactorium and the less dense basket-like innervation of the lateral septal nuclei could also be demonstrated. TH-positive cell bodies in a periglomerular position could be observed in the olfactory bulb. A few TH-positive cell bodies were observed in the area around the anterior commissure and in the cingulate cortex. In one area, the hippocampal formation, TH-positive dotlike structures were located in the position of the mossy fibres. In all probability they do not belong to monoamine neurons but may contain a cross-reacting protein. In general, the distribution and density of TH-positive terminals agrees well with extensive regional, biochemical studies on TH activity performed by other groups. Minor discrepancies are discussed. As stated in a parallel study on the distribution of TH in the mes- and diencephalon these findings indicate that TH activity is closely related to the amount of enzyme protein. The TH enzyme levels seem to be much higher in the DA than in the NA nerve terminals of the forebrain which would explain the preferential demonstration of DA terminals in the forebrain using TH antiserum and the high and low TH enzyme activity in DA and NA rich regions, respectively.

Animals↗

PubMed1977

[Morphology of the telencephalon of Salmo irideus (Teleostei). Golgi-impregnation study].

The telencephalon of Salmo irideus (Gibbons) was investigated by means of staining and silver impregnation techniques. It shows the fundamental plan characteristic for teleost species. The neurons in the various telencephalic nuclear areas are, in part, quite different with respect to their density of arrangement,migratory behavior, width of pericaryon and number of spines, inclusively. Neurons exhibiting a high degree of morphological differentiation (i.e. neurons of the stellate and pyramidal like type of differentiation) are located in the area dorsalis telencephali only. This telencephalic region is considered to be a functional homologon of limbic telencephalic structures of other vertebrates.

Animals↗

PubMedDate not supplied

[Visual projections into the telencephalon and diencephalon of the teleost fish Serranus scriba (electrophysiologic study)].

In acute experiments on Serranus scriba, two discrete foci of visual activity in the telencephalon were shown--in the dorsal pallium and in the central telencephalic area. The latency of focal potentials evoked by optic tectum stimulation was at least 2 msec shorter than that of the responses elicited by optic nerve stimulation. In the region of nucleus rotundus and some other thalamo-pretectal structures, focal potentials and single unit reactions to both types of stimulation were registered. Responses to optic tectum stimulation in nucleus pretectalis exhibited the shortest latency. It is suggested that visual impulses to the central telencephalic area are relayed consequently in the optic tectum and probably in more than one thalamo-pretectal nucleus.

Animals↗

PubMed1977

Preliminary study of the regenerative processes of the dorsal cortex of the telencephalon of Lacerta viridis.

The authors removed from Lacerta viridis specimens part of the dorsal hippocampus of one telencephalic hemisphere. The animals were sacrificed 110 and 260 days after the operation; 24 hours before the operation on the encephalon, each was dosed with 6--3H thymidine. An examination of the historadiographic slides showed a clear remedial process in the operated area which, 260 days after has renewed in thickness but was still minus its characteristic cellular layer. The area of the telencephalon affected by the remedial process was examined by the authors and they have put forward the hypothesis that in relation to the type of operation performed, said area is localized prevalently in the dorsal hippocampus of the caudal half of the telencephalic hemispherg. The authors have also shown that the remedial procress, though attenuated is still in progress. 260 days after the operation.

Animals↗

PubMed1978

[Postnatal changes in the regions bordering the ventricle in the telencephalon of the cat].

In frontal, sagittal and horizontal series of sections through the telencephalon of 15 cats the postnatal development of the periventricular regions has been examined. Structure, distribution and postnatal changes of the matrix, of a zone of undifferentiated cells near the ventricle, and of packets of undifferentiated cells, so-called cell nests, are described in detail. In cats aged from postnatal day 1 to 84, the following findings have been obtained: 1. At term, almost the entire lateral wall of the lateral ventricle is lined by a matrix layer. After birth, it undergoes involution at rates varying at different sites.--In the medial wall of the lateral ventricle, a matrix occurs only in cats aged 1--5 days in a region rostral to the lamina terminalis. 2. In newborn and young cats a less compact layer of undifferentiated cells with dark nuclei was found to abut on the matrix. Near the album, this layer is characterized by a cell-rich outer zone, called the cell wall. The cell content of the layer of undifferentiated cells increases up to the 11th to 16th postnatal day. Later on it decreases. 3. The cell nests consist of groups of closely packed cells with small nuclei and scanty cytoplasm. The cell nests may be round, ellipsoid, elongated or irregular in form. They are often localized in direct contact to blood vessels. The cell nests occur in certain predilection areas, particularly in the region of the frontal white matter and in the centrum semiovale. In most regions of the cerebral cortex where cell nests occur, their number increases up to the 11th to 16th postnatal day and later decreases. At the 40th day most of the cell nests have disappeared. 4. Within the matrix and the layer of undifferentiated cells near the ventricle, and also within the cell nests, cell divisions and cell deaths occur. The structural changes described are discussed with respect to postnatal development of the cerebral hemispheres.

Aging↗