Otolith organ or semicircular canal stimulation induces c-fos expression in unipolar brush cells and granule cells of cat and squirrel monkey

2005 ◽  
Vol 164 (3) ◽  
pp. 286-300 ◽  
Author(s):  
Gabriella Sekerková ◽  
Ema Ilijic ◽  
Enrico Mugnaini ◽  
James F. Baker
Keyword(s):  
Squirrel Monkey ◽  
Semicircular Canal ◽  
Granule Cells ◽  
Otolith Organ ◽  
Brush Cells ◽  
Unipolar Brush Cells ◽  
Fos Expression

Resurgent Na Currents in Four Classes of Neurons of the Cerebellum

2004 ◽  
Vol 92 (5) ◽  
pp. 2831-2843 ◽  
Author(s):  
Fatemeh S. Afshari ◽  
Krzysztof Ptak ◽  
Zayd M. Khaliq ◽  
Tina M. Grieco ◽  
N. Traverse Slater ◽  
...  
Keyword(s):  
Open Channel ◽  
Granule Cells ◽  
Na Channel ◽  
Na Channels ◽  
Brush Cells ◽  
Cerebellar Neurons ◽  
Na Currents ◽  
Unipolar Brush Cells ◽  
Resurgent Current ◽  
Resurgent Currents

Action potential firing rates are generally limited by the refractory period, which depends on the recovery from inactivation of voltage-gated Na channels. In cerebellar Purkinje neurons, the kinetics of Na channels appear specialized for rapid firing. Upon depolarization, an endogenous open-channel blocker rapidly terminates current flow but prevents binding of the “fast” inactivation gate. Upon repolarization, unbinding of the blocker produces “resurgent” Na current while allowing channels to recover rapidly. Because other cerebellar neurons, including granule cells, unipolar brush cells, and neurons of the cerebellar nuclei, also fire rapidly, we tested whether these cells might also express Na channels with resurgent kinetics. Neurons were acutely isolated from mice and rats, and TTX-sensitive Na currents were recorded under voltage clamp. Unlike Purkinje cells, the other cerebellar neurons produced only tiny resurgent currents in solutions optimized for voltage-clamping Na currents (50 mM Na+; Co2+ substitution for Ca2+). Under more physiological ionic conditions (155 mM Na+; 2 mM Ca2+ with 0.03 mM Cd2+), however, granule cells, unipolar brush cells, and cerebellar nuclear cells all produced robust resurgent currents. The increase in resurgent current, which was greater than predicted by the Goldman-Hodgkin-Katz equation, appeared to result from a combination of knock-off of open-channel blockers by permeating ions as well as relief of divalent block at negative potentials. These results indicate that resurgent current is typical of many cerebellar neurons and suggest that rapid open-channel block and unblock may be a widespread mechanism for restoration of Na channel availability in rapidly firing neurons.

scholarly journals Selective targeting of unipolar brush cell subtypes by cerebellar mossy fibers

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Timothy S Balmer ◽  
Laurence O Trussell
Keyword(s):  
Granule Cells ◽  
Mossy Fiber ◽  
Vestibular Nucleus ◽  
Mossy Fibers ◽  
Primary Afferents ◽  
Vestibular Organ ◽  
Brush Cells ◽  
Unipolar Brush Cell ◽  
Selective Targeting ◽  
Unipolar Brush Cells

In vestibular cerebellum, primary afferents carry signals from single vestibular end organs, whereas secondary afferents from vestibular nucleus carry integrated signals. Selective targeting of distinct mossy fibers determines how the cerebellum processes vestibular signals. We focused on vestibular projections to ON and OFF classes of unipolar brush cells (UBCs), which transform single mossy fiber signals into long-lasting excitation or inhibition respectively, and impact the activity of ensembles of granule cells. To determine whether these contacts are indeed selective, connectivity was traced back from UBC to specific ganglion cell, hair cell and vestibular organ subtypes in mice. We show that a specialized subset of primary afferents contacts ON UBCs, but not OFF UBCs, while secondary afferents contact both subtypes. Striking anatomical differences were observed between primary and secondary afferents, their synapses, and the UBCs they contact. Thus, each class of UBC functions to transform specific signals through distinct anatomical pathways.

scholarly journals Selective targeting of unipolar brush cell subtypes by cerebellar mossy fibers

2019 ◽  
Author(s):  
Timothy S. Balmer ◽  
Laurence O. Trussell
Keyword(s):  
Granule Cells ◽  
Mossy Fiber ◽  
Vestibular Nucleus ◽  
Mossy Fibers ◽  
Primary Afferents ◽  
Vestibular Organ ◽  
Brush Cells ◽  
Unipolar Brush Cell ◽  
Selective Targeting ◽  
Unipolar Brush Cells

AbstractIn vestibular cerebellum, primary afferents carry signals from single vestibular end organs, whereas secondary afferents from vestibular nucleus carry integrated signals. Selective targeting of distinct mossy fibers to postsynaptic cells determines how the cerebellum processes vestibular signals. We focused on vestibular projections to ON and OFF classes of unipolar brush cells (UBCs), which transform single mossy fiber signals into long-lasting excitation or inhibition respectively, and impact the activity of ensembles of granule cells. To determine whether these contacts are indeed selective, connectivity was traced back from UBC to specific ganglion cell, hair cell and vestibular organ subtypes. We show that a specialized subset of primary afferents contacts ON UBCs, but not OFF UBCs, while secondary afferents contact both subtypes. Striking anatomical differences were observed between primary and secondary afferents, their synapses, and the UBCs they contact. Thus, each class of UBC functions to transform specific signals through distinct anatomical pathways.

scholarly journals Visuo-Vestibular Information Processing by Unipolar Brush Cells in the Rabbit Flocculus

2015 ◽  
Vol 14 (5) ◽  
pp. 578-583 ◽  
Author(s):  
Robert A. Hensbroek ◽  
Tom J. H. Ruigrok ◽  
Boeke J. van Beugen ◽  
Jun Maruta ◽  
John I. Simpson
Keyword(s):  
Information Processing ◽  
Brush Cells ◽  
Vestibular Information ◽  
Unipolar Brush Cells

Properties of transmission at a giant glutamatergic synapse in cerebellum: the mossy fiber-unipolar brush cell synapse

1995 ◽  
Vol 74 (1) ◽  
pp. 24-42 ◽  
Author(s):  
D. J. Rossi ◽  
S. Alford ◽  
E. Mugnaini ◽  
N. T. Slater
Keyword(s):  
Nmda Receptors ◽  
Rise Time ◽  
Extracellular Space ◽  
Granule Cells ◽  
Mossy Fiber ◽  
Lucifer Yellow ◽  
Synaptic Cleft ◽  
Brain Regions ◽  
Patch Clamp Recording ◽  
Brush Cells

1. The synaptic activation by mossy fibers (MFs) of unipolar brush cells (UBCs) in the vestibular cerebellum (nodulus and uvula) was examined using patch-clamp recording methods in thin, rat cerebellar slices with Lucifer yellow-filled pipettes for subsequent fluorescence microscopic verification of the cell morphology. 2. UBCs were distinguished from adjacent granule cells in thin cerebellar slices in the uvula and nodulus regions by their larger soma diameters and short dendritic brush, greater whole-cell capacitance, and a prolonged, biphasic excitatory postsynaptic current (EPSC) to stimulation of MFs. 3. Thin-section transmission electron micrographs of the MF-UBC synapse displayed an unusually extensive area of synaptic apposition estimated to measure 12-40 microns2. The majority of UBCs was innervated by a single MF. At high magnification, individual clusters of presynaptic vesicles could be discerned, separated by regions of presynaptic membrane lacking vesicles, but apposed to continuous regions of postsynaptic density. Thus, after release, transmitter diffusion from the synaptic cleft must traverse considerable stretches of postsynaptic membrane before escape into extracellular space. In contrast, MF-granule cell synapses in these cerebellar regions resembled glutamate synapses in other brain regions in that the total synaptic area measured < or = 4 microns2. These synaptic junctions were flanked by short stretches of unspecialized plasma membrane, providing a short (0.5 micron) diffusional path from the site of neurotransmitter release to a branch point of the extracellular space. 4. The MF-evoked EPSC in UBCs was composed of a fast (10-90% rise time: 0.70 ms) and slow (10-90% rise time: 395 ms; 10-90% decay time: 3.1 s) component. The fast component was blocked by the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate (AMPA/KA) antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (10 microM) and displayed linear current-voltage (I-V) relations in the presence or absence of external magnesium. 5. The slow EPSC was also mediated by glutamate receptors, but in most neurons both AMPA/KA and N-methyl-D-aspartate (NMDA) receptors contributed to the slow EPSC, with the contribution of NMDA receptors predominating in the majority of cells. Consequently, although all cells displayed linear I-V relations in Mg(2+)-free saline, cells in which the slow EPSC was predominently mediated by NMDA receptors exhibited voltage-dependent rectification in the presence of external Mg2+ (1 mM). 6. With increasing postnatal age (10-30 d), the contribution made to the slow EPSC by NMDA receptors declined, with a reciprocal increase in the contribution being made by AMPA/KA receptors.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Electrophysiological, Morphological, and Topological Properties of Two Histochemically Distinct Subpopulations of Cerebellar Unipolar Brush Cells

2012 ◽  
Vol 11 (4) ◽  
pp. 1012-1025 ◽  
Author(s):  
Jin-Ah Kim ◽  
Gabriella Sekerková ◽  
Enrico Mugnaini ◽  
Marco Martina
Keyword(s):  
Topological Properties ◽  
Brush Cells ◽  
Unipolar Brush Cells

scholarly journals Preserved otolith organ function in caspase-3-deficient mice with impaired horizontal semicircular canal function

2015 ◽  
Vol 233 (6) ◽  
pp. 1825-1835 ◽  
Author(s):  
Patrick A. Armstrong ◽  
Scott J. Wood ◽  
Naoki Shimizu ◽  
Kael Kuster ◽  
Adrian Perachio ◽  
...  
Keyword(s):  
Semicircular Canal ◽  
Caspase 3 ◽  
Otolith Organ ◽  
Organ Function ◽  
Horizontal Semicircular Canal ◽  
Deficient Mice

scholarly journals Forward Signaling by Unipolar Brush Cells in the Mouse Cerebellum

2015 ◽  
Vol 14 (5) ◽  
pp. 528-533 ◽  
Author(s):  
Stijn van Dorp ◽  
Chris I. De Zeeuw
Keyword(s):  
Brush Cells ◽  
Mouse Cerebellum ◽  
Unipolar Brush Cells
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