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Results for “CEREBELLAR CORTEX”

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At least 1,117 records · Page 62Linked to original sources

PubMed1991

A monoclonal antibody to conotoxin reveals the distribution of a subset of calcium channels in the rat cerebellar cortex.

Voltage-sensitive calcium channels (VSCC) are a family of ionophores having different electrical and pharmacological properties. The omega-conotoxin GVIA (omega-CgTX) is a specific blocker of one subset of VSCCs. Because of the specificity of this toxin, a monoclonal anti-omega-CgTX antibody was generated against a omega-CgTX-key hole limpet hemocyanin conjugate and used as a specific marker to study VSCC distributions. This mab was shown to recognize omega-CgTX on Western blots and to display omega-CgTX-dependent immunoperoxidase staining of rat cerebellum. Incubation of fresh, unfixed sections of adult rat cerebellum in omega-CgTX followed by light fixation and peroxidase immunocytochemistry with mab anti-omega-CgTX revealed a specific pattern of labelling. All principal classes of cerebellar neurons were immunoreactive, but in general glial cells were not stained. Most interestingly, strong focal immunoreactivity was encountered at branching points of Purkinje cell dendrites. This characteristic staining pattern implies that a subset of VSCC is specifically concentrated in these regions and suggests that these channels may play a role in the functional integration of dendritic signals.

Animals↗

PubMed2002

The role of climbing and parallel fibers inputs to cerebellar cortex in navigation.

DA-HAN rats with partial or total lesion of climbing (CF) and parallel fibers (PF) inputs of the cerebellum were tested in a water task. Two different protocols were used, requiring to find either a non-visible or a visible platform. These two protocols were, respectively, designed to evaluate visuo-motor guidance (visible platform) and navigation (non-visible platform). Both groups of lesioned rats presented a deficit in the non-visible platform task but not in the visible platform one. The protocol of navigation we used was a fixed start-fixed arrival procedure. Totally lesioned animals were unable to learn to orient their body toward the non-visible platform and adopted instead a circling behavior. Our results suggest a role of cerebellar inputs (climbing (CF) and PF) in navigation.

Animals↗

PubMed2005

Developmental changes in concentrations and distributions of neurotrophins in the monkey cerebellar cortex.

Neurotrophins are involved in the survival, differentiation, migration and neurite outgrowth of various neuronal populations. Neurotrophins and their receptors are widely expressed in the developing cerebellum of various experimental animals. To gain some insight into the possible roles played by these molecules in monkey cerebellum, we examined the protein levels of BDNF, NT-4/5 and NT-3 and distributions of those neurotrophins and TrkC, a high affinity receptor for NT-3, in the cerebellum of developing macaque monkeys using ELISAs and immunohistochemical methods. We found that the level of BDNF increased during development, while the level of NT-3 was higher during embryonic stages and decreased toward adulthood. The level of NT-4/5 increased from embryonic stages to infant stages and gradually declined with age. Among the three neurotrophins, BDNF immunoreactivity was found in all kinds of cerebellar neurons, including all inhibitory interneurons, throughout the postnatal periods examined, indicating that BDNF may be an essential factor for the maintenance of cerebellar neural functions. The Bergmann glial fibers and the internal part of the external granule cell layer were strongly NT-3 immunopositive at the early postnatal stages, and more weakly immunoreactive toward adulthood. In addition, we found that the premigratory precursors of the granule cells were TrkC immunopositive at early postnatal stages. These findings suggest that NT-3 in Bergmann glial fibers may be involved in the migration of the premigratory granule cells.

Animals↗

PubMed1980

[Certain features of the vasocular-capillary network of the cerebellar cortex in dogs].

The vascular-capillary network of the dog cerebellum has been studied by means of the injection method. The capillary length in 1 mm3 of the vermis cortex averages to 520 mm in the molecular layer and 680 mm--in the granular layer. The mean diameter of the capillaries is 3 mkm. The capillary length both in the molecular and in the granular cortical layers at the fundus of sulci is 40-60% more, and the capillary diameter is 7-10% less than at the apices of the sulci.

Animals↗

PubMed1992

Expression of the carbohydrate epitope 3-fucosyl-N-acetyl-lactosamine (CD15) in the vertebrate cerebellar cortex.

The distribution of the carbohydrate epitope CD15 was investigated on paraffin sections of the brains of man and mammals (monkey, dog, rabbit, rat, mouse, dolphin), reptile, bird and fish by means of immunohistochemistry. This paper demonstrates a differential expression of the CD15 epitope in the cerebella of these various vertebrates. CD15 positivity was found on glial cells and neuronal structures. In adult brains two major distribution patterns were distinguished: one with very intense labelling of the molecular layer, for which the rat is representative, the other with very low immunoreactivity in this layer (mouse). Amongst the rodents (mouse, rat and rabbit), as well as the monkey and human, the positivity in the molecular layer could be attributed to Bergmann fibres of the Golgi epithelial cells. A typical parasagittal band pattern, present in the mouse molecular layer for CD15, which is absent in rat and rabbit molecular layer, is present during human cerebellar development. CD15 positivity on neuronal structures is found on parallel fibres in the developing human, on the lower stellate cells in the dog, and in climbing fibres of the dolphin and, presumably, the catfish too. Moreover, within the parrot cerebellum, large CD15-positive mossy fibre-like endings are found just at the infraplexiform layer.

Adolescent↗

PubMed1978

[Electron microscopic study of perisomatic process development in cerebellar cortex pyriform neurons during prenatal human ontogenesis].

Perisomatic processes are shown to be temporary morphological formations that appear within 16-28 weeks of embryogenesis, their development being characterized by a certain succession. Perisomatic processes form multiple synaptic complexes with axon endings of unknown origin adherent to perikaryons of pear-shaped neurons. These axon endings are supposed to belong to afferent climbing fibers of cerebellum stimulating differentiation of pear-shaped neurons, localization of these fibers causing a certain succession in the development of perisomatic processes.

Cell Differentiation↗

PubMed1998

Localization of the mGlu4a metabotropic glutamate receptor in rat cerebellar cortex.

The subcellular localization of the mGlu4a metabotropic glutamate receptor was investigated in rat cerebellum. At the light microscopical level, strong mGlu4a immunoreactivity was found in the molecular layer. A post-embedding immunogold method for electron microscopy revealed gold particles at the presynaptic sites of synapses made by parallel fiber terminals with dendritic spines of Purkinje cells. These observations support electrophysiological evidence indicating an autoreceptor function of mGlu4 receptors at these synapses.

Amino Acid Sequence↗

PubMed1984

Cerebellar histogenesis and synaptic maturation following pre- and postnatal alcohol administration. An electron-microscopic investigation of the rat cerebellar cortex.

Fetal alcohol syndrome was produced in rats by feeding an ethanol-enriched, vitamine -supplemented liquid diet over a period of 4 weeks before mating and throughout pregnancy. The amount of ethanol was equivalent to 38-40% of the daily calories; control animals were fed an isocaloric amount of sucrose. The offspring of experimental animals displayed a diminished birth weight. In contrast to previous experiments, the ethanol diet was also administered during the lactating period. On postnatal day 7, experimental animals and controls were killed by perfusion and the cerebella prepared for electron microscopy. Morphometric analysis showed a reduced number of Purkinje cells. On day 12, Purkinje cells of experimental animals displayed ultrastructurally fewer organelles. Furthermore, a delayed synaptogenesis in the molecular layer was demonstrated with osmium-zinc iodide and ethanolic phosphotungstic acid showing an immature appearance of the presynaptic grid and weaker stained synaptic cleft material. The following discussion deals with possible mechanisms underlying these alcohol-induced alterations of cerebellar synaptogenesis.

Animals↗

PubMed1986

[Developmental changes in the cerebellar cortex and a possible relation to sudden infant death].

The cerebellum cortex was examined in 109 newborns, sucklings and children up to 5 years of age. The persistence of external granular layer was detected in nine suddenly decreased sucklings in comparison with individuals having died for other causes. In some cases the persistence of external granular layer may reflect incomplete postnatal development in relation to the given age and it may provide explanation of morphological and functional immaturity of central nervous system in a sudden suckling's death.

Cerebellar Cortex↗

PubMed1988

[Effect of protein-calorie deficiency on the ultrastructure of synapses in the molecular layer of the cerebellar cortex in developing and adult animals].

The influence of protein-caloric deficiency on the ultrastructure of synapses in the molecular layer of the cerebellum has been quantitatively assessed in young and adult mice. It has been found that protein-caloric deficiency in the early postnatal period delays the time of axo-dendritic synapse development in the neuropil. Adult mice were more resistant to the influence of protein-caloric deficiency because of an increase in compensatory-adaptive reactions found in the cerebellum.

Animals↗

PubMed1995

[The structural transformations of the human cerebellar cortex from birth to 3 years].

Heterohronia of archi- and neocerebellar regions development was established by means of morphometric analysis of optical thickness, layers and parameters of Purkinje cells in monthly (first postnatal year) and yearly intervals in children from birth up to three years of age. Growth of the cortex diameter in flocculus was shown to occur earlier than in four-angular lobule and to be more intensive on the gyral apex than in deep regions of sulci. Growth of cortical thickness on the gyral apex is connected basically with the granular layer thickening, with the thickening of molecular and granular layers for the gyral lateral side and with that of molecular layer for the fundus of sulcus. Differences in the growth and differentiation speed were in Purkinje cells in topographically diverse cortical loci.

Aging↗

PubMed1978

[Features of the development of the dendrites of differentiating pyriform cerebellar cortex neurons in mammals and man].

Pecularities of development of the differentiating piriform neuron cerebellum cortex dendrite system in the mammals and in man were studied with light and electron microscopy. Three consequent stages are involved in the process: the formation of a dilated portion of apical (supranuclear) cytoplasm with an increased amount of organelles; the formation of a temporary apical cytoplasmic mitre (cone); the development of the dendrite system occurring on the background of reduction of this temporary cytoplasmic formation. In the course of differentiation, a distinct change of the dendrite cytoplasm contents from reticular to tubular ones takes place.

Animals↗

PubMed1993

Abnormal synaptic architecture in the cerebellar cortex of a new dystonic mutant mouse, Wriggle Mouse Sagami.

The 'Wriggle Mouse Sagami (WMS)' is a new neurological mutant with severe dystonic movements of the trunk and extremities whose pathological characters are transmitted by an autosomal recessive gene (wri). Manifestations first appear at 10 days to 2 weeks after birth and progress until 12 weeks of age. In spite of the severe dystonic movements, no marked abnormalities had been found in the cyto- or myeloarchitecture of the central nervous system or that of the peripheral nerves, except for the impaired development of the dendritic trees of the Purkinje cells. In this study we quantitatively demonstrated decreased synaptic connections of parallel fibers on the dendritic spines of the Purkinje cells as early as 2 weeks after birth. On the other hand, synaptic boutons on the dendritic shafts and somata of the Purkinje cells and synaptic bouton-like structures which contained synaptic vesicles but without synaptic membrane specialization, were significantly increased in the molecular layer at 9 weeks of age. Glutamic acid decarboxylase immunohistochemistry suggested that some of these increased synaptic boutons and other bouton-like structures may have originated in GABA interneurons, such as stellate cells, basket cells and Golgi cells, and in the cerebellar nuclei. Because of the severity of the manifestations, it appears that synaptic alteration in interneurons also occurs in the other parts of the CNS.

Animals↗

PubMed1985

Computer simulation of a cerebellar cortex compartment. II. An information learning and its recall in the Marr's memory unit.

Computer simulation experiments are described regarding information storage and retrieval at a network consisting of one Purkinje cell and 20,000 granule cells. The information content depends on a scheme type and the properties of Purkinje cells. It is shown that a practically attainable information record efficiency is of the order 0.6 bit per binary memorising synapse. Associative information recall is demonstrated for the Marr's memory unit and expressions are derived for an information-content estimation based on parameter values obtained by simulation. The consequences of this computer simulation for physiological experiments are extensively discussed.

Animals↗

PubMed1991

Histochemistry of glutamate metabolizing enzymes in the rat cerebellar cortex.

Applying catalytic enzyme histochemistry, glutamate dehydrogenase (GDH) and phosphate activated glutaminase (PAG) were demonstrated at the light microscopic level, and aspartate aminotransferase (AAT) was detected at the electron microscopic level. GDH staining appeared preferentially in glial cells (Bergmann glia and astrocytes), whereas AAT was localized only in neuronal structures. Cytoplasmic AAT was demonstrated in the perikarya and terminal plexus of basket cells, in the perikarya of stellate cells, in about 60% of the granule cells, in mossy fiber boutons, in numerous small boutons in the molecular layer, and in the axoplasm of numerous myelinated and unmyelinated fibers. PAG was observed in both neuronal structures (perikarya of granule and Purkinje cells) and in astrocytes and Bergmann glia.

Animals↗

PubMed2005

Postnatal changes of steroid receptor coactivator-1 immunoreactivity in rat cerebellar cortex.

Steroid receptor coactivator-1 (SRC-1) interacts with nuclear hormone receptors (NRs) to mediate their action in a ligand-dependent manner. Among such ligands, thyroid hormone (TH) is particularly crucial for brain development. The expression of many TH target genes is regulated by TH only for a limited critical period, although TH receptor (TR) expression is not greatly altered after such period. To alter TH sensitivity, other factors may be involved. We thus examined the changes in SRC-1 expression during postnatal development in the rat cerebellum by immunohistochemistry and Western blotting. Strong SRC-1 immunoreactivity (IR) was constantly seen in Purkinje cell from postnatal days (P) 2 to P30. SRC-1 IR was also constantly observed in the internal granule cell layer. However, it was negative in the external granule cell layer at P2 and P7, whereas a weak IR was detected in the premigratory zone at P15. SRC-1 IR was detected in the molecular layer after P15. These results indicate that although TR is almost ubiquitously expressed in the developing cerebellum, the TH sensitivity could vary in each subset of cells. By Western blotting, SRC-1 protein level was greatest at P15, at which time TH action may be obvious. Taken together, the differential expression of SRC-1 may be crucial in mediating TH action during cerebellar development.

Animals↗

PubMed1975

The effect of pre- and postnatal undernutrition on the development of the cerebellar cortex in the rat. II. Histochemical observations.

The effect of pre- and postnatal undernutrition on the neuronal enzymatic maturation of the neocerebellar hemispheral lobules VI b, VI c and VII (according to Larsell 1952) was studied. Postnatally oxidative enzyme histochemistry (LDH, SDH, NADH, NADPH, G6PDH) revealed a delayed enzymatic development in the cerebellum between days 8 and 22, as an effect of pre- and postnatal undernutrition. In the Purkinje cell apical cone a delayed increase in enzyme activities could be seen at days 8 to 11 as well as a delayed decrease in Purkinje cell perikaryal enzyme activities at days 11 to 14 post-partum. The retarded enzymatic development seemed to parallel the retarded morphological development (cf. Sima & Persson 1975).

Age Factors↗

PubMed1980

A topographic analysis of limbic and somatic inputs to the cerebellar cortex in the rat.

The effects of electrical stimulation of the fornix, snout, and limbs on the activity of electrophysiologically identified Purkinje cells were investigated. Extracellularly recorded responses were analyzed according to: latency; mode of termination as mossy or climbing fibers; and, whether excitatory or inhibitory responses were evoked. The positions of responsive cells were transposed onto a planar representation of the Purkinje cell layer of the rat cerebellum derived from a series of sagittal sections. Fornix responsive cells were found in the vermis of lobules IV, V, VI, and VII as well as in the paravermal regions of lobules II--VIIb. In addition, some evidence was obtained for a projection to lobulus simplex. Snout stimulation activated cells mainly in the vermis of lobule VI and also in adjacent lobules III, IV, V, and VIIa. A few responsive cells were also found in the paravermal regions of lobules V, VI, and VIIa and in the lateral portion of lobulus simplex. Forelimb responsive cells were located mainly in the vermis of lobules IV--VIa and in the paravermal protion of lobules III--VII. The few hindlimb cells encountered were located in the vermis and paravermis of lobules II--IV. The topographical overlap of the fornix projection with areas in receipt of forelimb, snout, neck, and auditory-visual teleceptor input suggests that the fornix-mediated information may modulate cerebellar circuits involved in postural adjustment, general orienting, and exploratory motor behavior.

Afferent Pathways↗