Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cerebellar Cortex”

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 595 records · Page 33Linked to original sources
PubMed1984

Adenosine selectively blocks parallel-fiber-mediated synaptic potentials in rat cerebellar cortex.

Electrophysiological techniques were used to study the efficacy of adenosine in modulating synaptic transmission mediated from convergent parallel- and climbing-fiber inputs to Purkinje cells. Our results indicate that adenosine application leads to selective blocking of parallel fiber-mediated synaptic activity but not of climbing fiber activity. Adenosine does not alter the action-potential excitability properties of the parallel fibers. However, application of gamma-aminobutyric acid (GABA), which directly affects Purkinje cell dendritic membranes [Malenka, R. C. & Kocsis, J. D. (1982) J. Neurophysiol. 48, 608-621], leads to reduction of both parallel- and climbing-fiber synaptic activity. These results support the proposals that adenosine receptors in the cerebellar cortex are selectively localized on the nonmyelinated parallel fibers and that the blocking action of adenosine is the result of a mechanism other than direct alteration of axon excitability.

Adenosine↗
PubMed1999

Metabotrop glutamate receptor type 1a expressing unipolar brush cells in the cerebellar cortex of different species: a comparative quantitative study.

Morphology, distribution and number of unipolar brush cells (UBCs) was studied in the cerebellar vermal lobules I-X of the chicken, rat, guinea pig, cat, and monkey using monoclonal mGluR1a antibody as a marker to visualise these recently described nerve cells (Mugnaini and Floris [1994] J. Comp. Neurol. 339:174-180; Mugnaini et al. [1994] Synapse 16:284-311). The morphological appearance of mGluR1a immunopositive UBCs is similar in all species investigated: they are small cells, having a single, relatively short and thick dendrite, terminating in brush-like dendrioles. Although this, probably excitatory, cell type can be found all over the cerebellar cortex, highest density of UBCs can be seen in the vermal cortex. The present study, therefore, was focused on the quantitative morphology and distribution of UBCs in the 10 lobules of the vermis. Calculating the number of UBCs/l Purkinje cell (PC), we have found differences in this value (average in vermal lobules I-X) from 1.04 in rat, 1.10 in chicken, 1.16 in guinea pig, 2.27 in monkey, and up to 2.44 in cat. The highest density of UBCs was observed in lobules I, IX, and X, whereas the lowest number of UBCs/l PC was found in lobules IV-VI (in the mammals) and in lobules VII-VIII (in the chicken). In mammals, particularly the monkey and cat, an increased presence of UBCs was observed in vermal sub-lobules VIc-VIIb,c, a region defined as the oculomotor vermis because of its role in the control of saccadic eye movement. There is also a basic difference between chicken and mammals in the distribution of UBCs within the lobules: in mammals, the lowest density of these nerve cells was found in the peripheral portion of the lobules, near to the pia, while in the chicken, in contrast, the density of UBCs was the highest subpially with fewer UBCs located in the deepest curvature of the lobules. Finally, the functional significance of the differences in the density and in the distribution pattern of UBCs in the cerebellar vermis between the phylogenetically different species investigated is briefly discussed.

Animals↗
PubMed2004

Inactivation of calcium-binding protein genes induces 160 Hz oscillations in the cerebellar cortex of alert mice.

Oscillations in neuronal populations may either be imposed by intrinsically oscillating pacemakers neurons or emerge from specific attributes of a distributed network of connected neurons. Calretinin and calbindin are two calcium-binding proteins involved in the shaping of intraneuronal Ca2+ fluxes. However, although their physiological function has been studied extensively at the level of a single neuron, little is known about their role at the network level. Here we found that null mutations of genes encoding calretinin or calbindin induce 160 Hz local field potential oscillations in the cerebellar cortex of alert mice. These oscillations reached maximum amplitude just beneath the Purkinje cell bodies and are reinforced in the cerebellum of mice deficient in both calretinin and calbindin. Purkinje cells fired simple spikes phase locked to the oscillations and synchronized along the parallel fiber axis. The oscillations reversibly disappeared when gap junctions or either GABA(A) or NMDA receptors were blocked. Cutaneous stimulation of the whisker region transiently suppressed the oscillations. However, the intrinsic somatic excitability of Purkinje cells recorded in slice preparation was not significantly altered in mutant mice. Functionally, these results suggest that 160 Hz oscillation emerges from a network mechanism combining synchronization of Purkinje cell assemblies through parallel fiber excitation and the network of coupled interneurons of the molecular layer. These findings demonstrate that subtle genetically induced modifications of Ca2+ homeostasis in specific neuron types can alter the observed dynamics of the global network.

Action Potentials↗
PubMed2006

Co-localization of glycine and gaba immunoreactivity in interneurons in Macaca monkey cerebellar cortex.

Previous work demonstrates that the cerebellum uses glycine as a fast inhibitory neurotransmitter [Ottersen OP, Davanger S, Storm-Mathisen J (1987) Glycine-like immunoreactivity in the cerebellum of rat and Senegalese baboon, Papio papio: a comparison with the distribution of GABA-like immunoreactivity and with [3H]glycine and [3H]GABA uptake. Exp Brain Res 66(1):211-221; Ottersen OP, Storm-Mathisen J, Somogyi P (1988) Colocalization of glycine-like and GABA-like immunoreactivities in Golgi cell terminals in the rat cerebellum: a postembedding light and electron microscopic study. Brain Res 450(1-2):342-353; Dieudonne S (1995) Glycinergic synaptic currents in Golgi cells of the rat cerebellum. Proc Natl Acad Sci U S A 92:1441-1445; Dumoulin A, Triller A, Dieudonne S (2001) IPSC kinetics at identified GABAergic and mixed GABAergic and glycinergic synapses onto cerebellar Golgi cells. J Neurosci 21(16):6045-6057; Dugue GP, Dumoulin A, Triller A, Dieudonne S (2005) Target-dependent use of coreleased inhibitory transmitters at central synapses. J Neurosci 25(28):6490-6498; Zeilhofer HU, Studler B, Arabadzisz D, Schweizer C, Ahmadi S, Layh B, Bosl MR, Fritschy JM (2005) Glycinergic neurons expressing enhanced green fluorescent protein in bacterial artificial chromosome transgenic mice. J Comp Neurol 482(2):123-141]. In the rat cerebellum glycine is not released by itself but is released together with GABA by Lugaro cells onto Golgi cells [Dumoulin A, Triller A, Dieudonne S (2001) IPSC kinetics at identified GABAergic and mixed GABAergic and glycinergic synapses onto cerebellar Golgi cells. J Neurosci 21(16):6045-6057] and by Golgi cells onto unipolar brush and granule cells [Dugue GP, Dumoulin A, Triller A, Dieudonne S (2005) Target-dependent use of coreleased inhibitory transmitters at central synapses. J Neurosci 25(28):6490-6498]. Here we report, from immunolabeling evidence in Macaca cerebellum, that interneurons in the granular cell layer are glycine+ at a density of 120 cells/linear mm. Their morphology indicates that they include Golgi and Lugaro cell types with the majority containing both glycine and GABA or glutamic acid decarboxylase. These data are consistent with the proposal that, as in the rat cerebellum, these granular cell layer interneurons corelease glycine and GABA in the primate cerebellum. The patterns of labeling for glycine and GABA within Golgi and Lugaro cells also indicate that there are biochemical sub-types which are morphologically similar. Further, we find that glycine, GABA and glutamic acid decarboxylase identified candelabrum cells adjacent to the Purkinje cells which is the first time that this interneuron has been reported in primate cerebellar cortex. We propose that candelabrum cells, like the majority of Golgi and Lugaro cells, release both glycine and GABA.

Animals↗
PubMedDate not supplied

Amyloid plaques in cerebellar cortex and the integrity of Purkinje cell dendrites.

We probed serial and near serial sections of cerebellum from 13 Alzheimer's disease (AD), 10 older Down's syndrome (DS) patients, and 9 age-matched, non-AD controls, using single and double labeling immunohistochemistry to investigate the pathologic consequences of beta-amyloid or A4 (A beta) deposits in cerebellum and their relationship to Purkinje cells (PCs). Our data showed that A beta deposits in cerebellum of AD and older DS adults only form diffuse or preamyloid plaques and the density of A beta lesions per unit area of molecular layer correlated with the number of PCs per unit length of the subjacent PC layer in double immunostained sections (r = 0.85; p < 0.001). About 65% of these cerebellar A beta deposits were in physical contact with PC dendrites. No A beta plaques were found in the cerebellum of controls. Despite the abundance of A beta deposits in the cerebellar cortex of AD and older DS patients, neither PC bodies nor PC dendrites in physical contact with A beta lesions showed evidence of structural abnormalities.

Adolescent↗
PubMed1988

Endogenous opioid systems and neural development: ultrastructural studies in the cerebellar cortex of infant and weanling rats.

Endogenous opioid systems participate in regulating the development of the nervous system. Opioid antagonists like naltrexone (NTX) perturb the relationship between endogenous opioids and opioid receptors quite effectively and reveal the function(s) of endogenous opioid systems during neuro-ontogeny. In this study, the effects of NTX, as well as the repercussions of modulation of endogenous opioid systems during critical stages of neural ontogeny, have been examined at the electron microscopic level of resolution in infant (10 day) and weanling (21 day) rats. Preweaning rats were subjected to complete (50 mg/kg NTX) or intermittent (1 mg/kg NTX) daily receptor blockade. Extensive ultrastructural examinations were conducted on the external germinal (granule), molecular, Purkinje, internal granule, and medullary layers of the cerebellar cortex. The NTX groups had striking similarities in morphology to that of controls at postnatal days 10 and 21. These results support the hypothesis that endogenous opioid systems act as trophic factors as they regulate growth; their effects on cell growth and survival, however, do not alter the basic ultrastructural morphology of the cells. Moreover, these data further strengthen the validity of paradigms utilizing opioid antagonists to explore the relationship of endogenous opioid-opioid receptor interactions and neural morphogenesis.

Aging↗
PubMed2007

Identification of aldolase C compartments in the mouse cerebellar cortex by olivocerebellar labeling.

Aldolase C (zebrin II) is expressed in Purkinje cells aligned in complicated longitudinal stripe-shaped compartments. The tight link between these aldolase C compartments and the topographic olivocerebellar projection to them has made it possible to identify each compartment as a target of a specific subarea of the inferior olive and thus as a functionally distinct entity in the rat. However, it is unknown whether the overall organization of aldolase C compartments is preserved in other mammals. In this study, we tried to clarify this organization in the mouse, which is more useful in genetic studies than the rat, by identifying each aldolase C compartment in terms of the olivocerebellar projection pattern. First, aldolase C compartments were reconstructed from serial sections throughout the cerebellar cortex. Aldolase C and olivocerebellar climbing fibers were then doubly labeled by small injections of biotinylated dextran amine into various areas of the inferior olive. Climbing fibers were topographically distributed on a specific linked pair of aldolase C compartments in the rostral and caudal cerebellum. The overall relationship between aldolase C compartments and the topographic olivocerebellar projection to them in the mouse was similar to that in the rat, except for some minor differences, suggesting that the aldolase C compartments and olivocerebellar projection are organized according to a common fundamental organization in the mouse and rat. This allowed the unequivocal identification of all aldolase C compartments in the mouse by referring to the definition and nomenclature in the rat.

Animals↗
PubMed2003

Spike firing in the lateral cerebellar cortex correlated with movement and motor parameters irrespective of the effector limb.

Neuronal signals in the lateral aspect of the macaque cerebellar cortex were studied during a visually guided reaching task. During the performance of this task, the firing rate of most neurons was significantly modulated when reaching with either the ipsilateral or the contralateral arm. In some of these reach-modulated cells, we found that spike firing was correlated with the direction and speed of the reach. These correlations with motor parameters were present during reaching with either the ipsilateral or the contralateral arm. Based on these observations we suggest that spike firing in the lateral cerebellum was correlated with movement and motor parameters irrespective of the effector limb.

Action Potentials↗
PubMed1993

Location of profilin at presynaptic sites in the cerebellar cortex; implication for the regulation of the actin-polymerization state during axonal elongation and synaptogenesis.

Profilin is a 15 kDa protein that binds actin monomers and inhibits their polymerization in vitro. The actin-profilin complex can be rapidly dissociated in vitro by phosphatidylinositol-4,5-bis-phosphate, providing a mechanism for regulating actin assembly-disassembly cycles during cell motile events. We have used a polyclonal antibody to calf spleen profilin to analyse the developmental expression and cellular distribution of profilin in the rat cerebellum and cultured cortical neurons. Immature neurons contain large amount of profilin both in vivo and in vitro. Immunofluorescence showed it to be present in developing neurites and growth cones but not in the filopodia of cortical neurons in culture. Profilin immunoreactivity was intense in the parallel fibres, the granule cell axons of the cerebellar cortex, at the time when they are elongating. Purkinje cell dendrites were not labelled. Profilin immunostaining was present in presynaptic varicosities, but not in dendritic spines within the molecular layer of juvenile and adult rats. The profilin concentration was higher in synaptosomes than in the total cerebellum during the second and third postnatal weeks, a period of intense synaptogenesis. Thus, profilin may help regulate actin polymerization and depolymerization during axonal elongation and synaptogenesis. Its restriction to the presynaptic site in the adult suggests that it may also be involved in the regulation of the release of synaptic vesicles.

Actins↗
PubMed1980

Somatotopic organization of climbing fiber projections from low threshold cutaneous afferents to pars intermedia of cerebellar cortex in the cat.

The fine detail of climbing fiber projections to large areas of the pars intermedia of lobule V was demonstrated by means of low threshold natural cutaneous stimulation. These projections formed a complex mediolateral organization of patches that were elongated in the anteroposterior direction. In general, distal forelimb was represented medially and the face represented laterally, although there were also elongated patches of cells that did not respond to any cutaneous stimulus presentation. The entire ipsilateral anterior quadrant of the body was represented in lobules Vb, c, d with the addition of face projections which extended slightly across the midline. Ipsilateral hindlimb patches were observed in lobule Va. Although the boundary between patches was quite sharp, a slight overlap of the patches within the mosaic was often observed. In these areas of overlap, some cells possessed receptive fields that encompassed, either continuously or discontinuously, cutaneous areas of both the adjacent patches. It is proposed that the cerebellar cortex could correlate event timing in the climbing fiber patches with 'on-line' information relating the parameters of movement in the granule cell parallel fiber system, and that the areas described in the present study could mediate 'spatially organized and skilled movements' in the animal's repertoire, which involve paw-face-mouth interaction, such as feeding, cleaning and grooming.

Afferent Pathways↗
PubMed1988

Characterization of microtubule-associated protein 2 from mouse brain and its localization in the cerebellar cortex.

Microtubule-associated protein (MAP) 2 was purified from the microtubule fraction of mouse brain by heat treatment and BioGel A-5m gel filtration. The purified preparation showed a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis using both a gradient gel (3.75-12.5%) and a low-percentage gel (5%), a finding indicating that MAP2B was absent under the conditions used. Amino acid analysis revealed that mouse MAP2 was an acidic protein with an isoelectric point (pI 4.5) and amino acid composition similar to those of porcine brain MAP2. Immunoblot analysis indicated that the antigens that reacted with MAP2 antiserum were present in large quantities in mouse brain. However, we also found a weak reaction in various tissues other than brain, and the major antigens involved were recognized to be common molecular species with the same molecular mass, 162 and 170 kilodaltons. Using antiserum against mouse brain MAP2, the developmental localization patterns of MAP2 in the mouse cerebellar cortex were studied by immunohistochemistry. MAP2 was mainly localized in the neuronal cells throughout development, with the expression in Purkinje cell dendrites being especially remarkable in the growth of arborization from postnatal day 3 to day 20. At the mature stage, the reaction was strong in the dendritic tree but very weak in the proximal dendrites and cell bodies.

Amino Acids↗
PubMed1994

Developmental dynamics of Purkinje cells and dendritic spines in rat cerebellar cortex.

Quantitative morphological changes of the developing Purkinje cells were studied from 6 to 90 postnatal (PN) days in the IVth lobule of vermis in the cerebellum of rats. The soma size (mean diameter) of Purkinje cells increased rapidly between 6 PN (on average 10 microns) and 18 PN (about 17 microns) days; it did not change between 18 and 25 PN days, but increased moderately again between 25 and 48 PN days (22-23 microns) and stabilized on the same value. In contrast, the number of Purkinje cells/100 microns (the "linear density") decreased rapidly from 6 to 18 PN days. The molecular layer area belonging to 1 Purkinje cell increased rapidly from 6 to 25 PN days (from about 370 to 6,200 microns 2) and less rapidly between PN days 30 to 48 (up to 9,300 microns 2), followed by a moderate decrease at PN day 90 (about 6,600 microns 2). The volume belonging to 1 Purkinje cell dendritic arbor was about 5,500 microns 3 at PN day 6, 93,000 microns 3 at PN day 25, and 100,000 microns 3 at PN day 90. The numerical density of dendritic spines in the molecular layer showed a biphasic curve: a rapid increase from PN days 6 to 21 followed by a significant but short decrease at PN day 25, moderate rise from PN days 25 to 48, and a subsequent decline between PN days 48 and 90. The number of spines belonging to 1 Purkinje cell showed two developmental "peaks": the first peak at 21 PN days was moderate (5.6 x 10(4) spines/Purkinje cell) while the second maximum at 48 PN days was more significant (1.2 x 10(5) spines/Purkinje cell), which then declined to 6.3 x 10(4) spines/Purkinje cell at PN day 90. It is suggested that the temporary overproduction and the following decline in the number of Purkinje dendritic spines during the development of the cerebellar cortex may be the morphological indicator of the dynamics of synaptogenetic and of synaptic stabilization processes.

Animals↗
PubMedDate not supplied

Spontaneous and evoked activities of interpositus nucleus neurons before and after lesion of the cerebellar cortex.

Spontaneous and evoked activities of nucleus interpositus neurons (IN) of the cerebellum were examined before and after cerebellar paravermal cortex lesions in cats anesthetized with alpha-chloralose. It was found that spontaneous activity increased dramatically following cortical ablation: before the lesion only 4% of cells encountered fired at a rate exceeding 80 impulses/sec., whereas up to 40% discharged at this rate postoperatively. Responses to paw stimulation were also altered: the initial excitation was lengthened from 8.5 to 15.8 msec; narrow; trough causing segmentation in this excitation, which seems to result from Purkinje cell inhibition, was absent; and the succeeding inhibitory period was reduced in duration by 50%. Also after the lesion there was a strong tendency for the neurons to discharge in bursts. It is suggested that changes in cell activity in the IN following cortical lesion unveil neural mechanisms of motor disturbances in lesioned cats.

Action Potentials↗
PubMed2002

Neuronal activity related to the visual representation of arm movements in the lateral cerebellar cortex.

Testing the hypothesis that the lateral cerebellum forms a sensory representation of arm movements, we investigated cortical neuronal activity in two monkeys performing visually guided step-tracking movements with a manipulandum. A virtual target and cursor image were viewed co-planar with the manipulandum. In the normal task, manipulandum and cursor moved in the same direction; in the mirror task, the cursor was left-right reversed. In one monkey, 70- and 200-ms time delays were introduced on cursor movement. Significant task-related activity was recorded in 31 cells in one animal and 142 cells in the second: 10.2% increased activity before arm movements onset, 77.1% during arm movement, and 12.7% after the new position was reached. To test for neural representation of the visual outcome of movement, firing rate modulation was compared in normal and mirror step-tracking. Most task-related neurons (68%) showed no significant directional modulation. Of 70 directionally sensitive cells, almost one-half (n = 34, 48%) modulated firing with a consistent cursor movement direction, many fewer responding to the manipulandum direction (n = 9, 13%). For those "cursor-related" cells tested with delayed cursor movement, increased activity onset was time-locked to arm movement and not cursor movement, but activation duration was extended by an amount similar to the applied delay. Hence, activity returned to baseline about when the delayed cursor reached the target. We conclude that many cells in the lateral cerebellar cortex signaled the direction of cursor movement during active step-tracking. Such a predictive representation of the arm movement could be used in the guidance of visuo-motor actions.

Action Potentials↗