Journal of Vestibular Research - Volume 21, issue 1

Authors: Peusner, Kenna D.

Article Type: Introduction

DOI: 10.3233/VES-2011-0398

Citation: Journal of Vestibular Research, vol. 21, no. 1, pp. 1-3, 2011

Authors: Beraneck, Mathieu | Straka, Hans

Article Type: Research Article

Abstract: Second-order vestibular neurons (2°VN) are the central element for the transformation of body motion-related sensory signals into extraocular motor commands for retinal image stabilization during locomotion. The wide range of motion dynamics necessitates sensory signal transformation in parallel, frequency-tuned channels. Accordingly, in various vertebrates, 2°VN have been shown to form differently tuned functional subgroups. In frog, these neurons subdivide into two separate populations with distinctly different intrinsic membrane properties, discharge dynamics and synaptic response characteristics. Frog tonic 2°VN exhibit low-pass filter characteristics and membrane properties that cause amplification of synaptic inputs, whereas phasic 2°VN form band-pass filters that allow frequency-dependent …shunting of repetitive inputs. The differential, yet complementary membrane properties render tonic 2°VN particularly suitable for synaptic integration and phasic 2°VN for differentiation and event detection. Differential insertion of the two cell types into local circuits reinforces the functional consequences of the intrinsic membrane properties, respectively. As a consequence, the synergy of cellular and network properties creates sets of neuronal elements with particular filter characteristics that form flexible, frequency-tuned components for optimal transformation of all dynamic aspects of body motion-related multisensory signals. Show more

Keywords: Membrane properties, low-pass filter, high-pass filter, semicircular canal, macula organ, vestibulo-ocular reflex, potassium conductances

DOI: 10.3233/VES-2011-0396

Citation: Journal of Vestibular Research, vol. 21, no. 1, pp. 5-19, 2011

Authors: Popratiloff, Anastas | Shao, Mei | Hirsch, June C. | Peusner, Kenna D.

Article Type: Research Article

Abstract: The principal cells of the chick tangential vestibular nucleus offer a simple neuron model to study signal processing in second-order, vestibular reflex projection neurons. The principal cells represent a relatively uniform population of vestibular nuclei neurons which receive a major input from the primary vestibular fibers and send axons to targets mainly involved in the vestibuloocular reflexes. Here, studies performed on ion channels involved in the emergence and establishment of signal processing in this morphologically-identified subset of vestibular nuclei neurons are reviewed, including the AMPA glutamate receptor subunits GluR1, GluR2, GluR3, and GluR4 and the potassium channel subunits Kv1.1 and …Kv1.2. Show more

Keywords: Emergence of spike firing pattern, immunocytochemistry, confocal imaging

DOI: 10.3233/VES-2011-0393

Citation: Journal of Vestibular Research, vol. 21, no. 1, pp. 21-31, 2011

Authors: Kolkman, Kristine E. | Moghadam, Setareh H. | du Lac, Sascha

Article Type: Research Article

Abstract: Signal processing in the vestibular system is influenced by the intrinsic physiological properties of neurons that differ in neurotransmitters and circuit connections. Do membrane and firing properties differ across functionally distinct cell types? This study examines the intrinsic physiology of neurons in the medial vestibular nucleus (MVN) and nucleus prepositus hypoglossi (NPH) which express different neurotransmitters and have distinct axonal projections. NPH neurons expressing fluorescent proteins in glutamatergic, glycinergic, or GABAergic neurons were targeted for whole-cell patch recordings in brainstem slices obtained from transgenic mouse lines (YFP-16, GlyT2, and GIN). Recordings from MVN neurons projecting to the spinal cord, reticular …formation, or oculomotor nucleus were obtained by targeting fluorescent neurons retrogradely labeled from tracer injections. Intrinsic physiological properties of identified neurons exhibited continuous variations but tended to differ between functionally defined cell types. Within the NPH, YFP-16 neurons had the narrowest action potentials and highest evoked firing rates and expressed high levels of Kv3.3 proteins, which speed repolarization. MVN neurons projecting to the spinal cord and oculomotor nucleus had similar action potential waveforms, but oculomotor-projecting neurons had higher intrinsic gains than those projecting to the spinal cord. These results indicate that intrinsic membrane properties are differentially tuned in MVN and NPH neurons subserving different functions. Show more

Keywords: Glycinergic, GABAergic, glutamatergic, vestibulospinal, oculomotor

DOI: 10.3233/VES-2011-0394

Citation: Journal of Vestibular Research, vol. 21, no. 1, pp. 33-47, 2011

Authors: Holstein, Gay R. | Martinelli, Giorgio P. | Friedrich, Victor L.

Article Type: Research Article

Abstract: The vestibular system senses the movement and position of the head in space and uses this information to stabilize vision, control posture, perceive head orientation and self-motion in three-dimensional space, and modulate autonomic and limbic activity in response to locomotion and changes in posture. Most vestibular signals are not consciously perceived and are usually appreciated through effector pathways classically described as the vestibulo-ocular, vestibulo-spinal, vestibulo-collic and vestibulo-autonomic reflexes. The present study reviews some of the recent data concerning the connectivity and chemical anatomy of vestibular projections to autonomic sites that are important in the sympathetic control of blood pressure.

Keywords: Vestibular nuclei, vestibulo-sympathetic pathways, vestibulo-sympathetic reflex, vestibulo-autonomic control

DOI: 10.3233/VES-2011-0395

Citation: Journal of Vestibular Research, vol. 21, no. 1, pp. 49-62, 2011