Purkinje Cell Synapses Target Physiologically Unique Brainstem Neurons

Sekirnjak, Chris; Vissel, Bryce; Bollinger, Jacob; Faulstich, Michael E.; du, Sascha

doi:10.1523/jneurosci.23-15-06392.2003

Cited by 84 publications

(82 citation statements)

References 35 publications

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“…Prior work has further shown that neurons that receive inputs from the flocculus are type B neurons (Babalian and Vidal 2000;Sekirnjak et al 2003). Thus at least a subset of type B cells that have been described in in vitro studies are likely to correspond to the floccular target/eye-head neurons that have previously been described in in vivo studies and have been shown to play an important role in visually induced VOR motor learning in primates (Blazquez et al 2006;Lisberger et al 1994).…”

Section: Bridging the Gap: The Relation Between In Vivo And In Vitro mentioning

confidence: 83%

Activity of Vestibular Nuclei Neurons During Vestibular and Optokinetic Stimulation in the Alert Mouse

Beraneck¹,

Cullen²

2007

Journal of Neurophysiology

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As a result of the availability of genetic mutant strains and development of noninvasive eye movements recording techniques, the mouse stands as a very interesting model for bridging the gap among behavioral responses, neuronal response dynamics studied in vivo, and cellular mechanisms investigated in vitro. Here we characterized the responses of individual neurons in the mouse vestibular nuclei during vestibular (horizontal whole body rotations) and full field visual stimulation. The majority of neurons (∼2/3) were sensitive to vestibular stimulation but not to eye movements. During the vestibular-ocular reflex (VOR), these neurons discharged in a manner comparable to the “vestibular only” (VO) neurons that have been previously described in primates. The remaining neurons [eye-movement-sensitive (ES) neurons] encoded both head-velocity and eye-position information during the VOR. When vestibular and visual stimulation were applied so that there was sensory conflict, the behavioral gain of the VOR was reduced. In turn, the modulation of sensitivity of VO neurons remained unaffected, whereas that of ES neurons was reduced. ES neurons were also modulated in response to full field visual stimulation that evoked the optokinetic reflex (OKR). Mouse VO neurons, however, unlike their primate counterpart, were not modulated during OKR. Taken together, our results show that the integration of visual and vestibular information in the mouse vestibular nucleus is limited to a subpopulation of neurons which likely supports gaze stabilization for both VOR and OKR.

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Section: Bridging the Gap: The Relation Between In Vivo And In Vitro mentioning

confidence: 83%

Activity of Vestibular Nuclei Neurons During Vestibular and Optokinetic Stimulation in the Alert Mouse

Beraneck¹,

Cullen²

2007

Journal of Neurophysiology

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“…Cerebellar slices were prepared from either C57BL/6 or L7-GFP (C57BL/6 background) (Sekirnjak et al, 2003) mice on postnatal day 15 (P15) to P29 (mean of P21). When noted, experiments were done on Wistar rats, aged P36 -P39.…”

Section: Methodsmentioning

confidence: 99%

Relative Contributions of Axonal and Somatic Na Channels to Action Potential Initiation in Cerebellar Purkinje Neurons

2006

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Neuronal excitability is likely to be regulated by the site of action potential initiation, the location on a neuron that crosses threshold first. Although initiation is axonal in many neurons, in Purkinje cells, somatic conductances can generate spontaneous action potentials, suggesting that the perisomatic region (soma and/or initial segment) contributes to spike initiation and may regulate firing. To identify directly the cellular regions at which Na channel modulation significantly influences firing, we measured spontaneous and evoked action potentials in Purkinje cells in cerebellar slices from postnatal day 14 -28 mice while applying drugs locally to either the soma/initial segment or the first node of Ranvier. Na currents were decreased by tetrodotoxin (TTX) or increased by ␤-pompilidotoxin (␤-PMTX). Dual somatic and axonal recordings indicated that spike thresholds and input-output curves were sensitive to TTX or ␤-PMTX at the perisomatic region but were unchanged by either drug at the first node. When perisomatic Na channel availability was reduced with subsaturating TTX, however, the input-output curve became shallower during additional TTX block of nodal channels, revealing a latent role for nodal Na channels in facilitating firing. In perisomatic TTX, axons failed to generate spontaneous or evoked spike trains. In contrast, choline block of the initial segment alone altered normal input-output curves. The data suggest that, although the first node reliably follows action potentials, spike initiation in Purkinje neurons occurs in the initial segment. Moreover, Purkinje cell output depends on the density, availability, and kinetics of perisomatic Na channels, a characteristic that may distinguish spontaneously firing from quiescent neurons.

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“…The presence of a cerebellar inhibition in some phasic 2°VNs makes these neurons equivalent to mammalian floccular target neurons (FTN) in the MVN (De Zeeuw et al, 1994;Lisberger, 1998). In rodents, these neurons were shown to form a specific subpopulation of type B MVN neurons (Babalian and Vidal, 2000;Sekirnjak et al, 2003). Thus, a differentially organized Purkinje cell-mediated inhibition in equivalent subpopulations of vestibular neurons seems to be another conserved feature of vertebrate vestibular signal processing.…”

Section: Inhibitory Control Of Vestibular Responsesmentioning

confidence: 99%

Differential Dynamic Processing of Afferent Signals in Frog Tonic and Phasic Second-Order Vestibular Neurons

Pfanzelt¹,

Rössert²,

Rohregger³

et al. 2008

J. Neurosci.

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The sensory-motor transformation of the large dynamic spectrum of head-motion-related signals occurs in separate vestibulo-ocular pathways. Synaptic responses of tonic and phasic second-order vestibular neurons were recorded in isolated frog brains after stimulation of individual labyrinthine nerve branches with trains of single electrical pulses. The timing of the single pulses was adapted from spike discharge patterns of frog semicircular canal nerve afferents during sinusoidal head rotation. Because each electrical pulse evoked a single spike in afferent fibers, the resulting sequences with sinusoidally modulated intervals and peak frequencies up to 100 Hz allowed studying the processing of presynaptic afferent inputs with in vivo characteristics in second-order vestibular neurons recorded in vitro in an isolated whole brain. Variation of pulse-train parameters showed that the postsynaptic compound response dynamics differ in the two types of frog vestibular neurons. In tonic neurons, subthreshold compound responses and evoked discharge patterns exhibited relatively linear dynamics and were generally aligned with pulse frequency modulation. In contrast, compound responses of phasic neurons were asymmetric with large leads of subthreshold response peaks and evoked spike discharge relative to stimulus waveform. These nonlinearities were caused by the particular intrinsic properties of phasic vestibular neurons and were facilitated by GABAergic and glycinergic inhibitory inputs from tonic type vestibular interneurons and by cerebellar circuits. Coadapted intrinsic filter and emerging network properties thus form dynamically different neuronal elements that provide the appropriate cellular basis for a parallel processing of linear, tonic, and nonlinear phasic vestibulo-ocular response components in central vestibular neurons.

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Purkinje Cell Synapses Target Physiologically Unique Brainstem Neurons

Cited by 84 publications

References 35 publications

Activity of Vestibular Nuclei Neurons During Vestibular and Optokinetic Stimulation in the Alert Mouse

Activity of Vestibular Nuclei Neurons During Vestibular and Optokinetic Stimulation in the Alert Mouse

Relative Contributions of Axonal and Somatic Na Channels to Action Potential Initiation in Cerebellar Purkinje Neurons

Differential Dynamic Processing of Afferent Signals in Frog Tonic and Phasic Second-Order Vestibular Neurons

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