scholarly journals Oscillatory and Intrinsic Membrane Properties of Guinea Pig Nucleus Prepositus Hypoglossi Neurons In Vitro

2006 ◽  
Vol 96 (1) ◽  
pp. 175-196 ◽  
Author(s):  
Erwin Idoux ◽  
Mauro Serafin ◽  
Patrice Fort ◽  
Pierre-Paul Vidal ◽  
Mathieu Beraneck ◽  
...  
Keyword(s):  
Vestibular Nucleus ◽  
Discharge Rate ◽  
Oscillatory Behavior ◽  
Membrane Properties ◽  
Medial Vestibular Nucleus ◽  
Relative Role ◽  
Type D ◽  
Highly Nonlinear ◽  
Prepositus Hypoglossi

Numerous models of the oculomotor neuronal integrator located in the prepositus hypoglossi nucleus (PHN) involve both highly tuned recurrent networks and intrinsic neuronal properties; however, there is little experimental evidence for the relative role of these two mechanisms. The experiments reported here show that all PHN neurons (PHNn) show marked phasic behavior, which is highly oscillatory in ∼25% of the population. The behavior of this subset of PHNn, referred to as type D PHNn, is clearly different from that of the medial vestibular nucleus neurons, which transmit the bulk of head velocity-related sensory vestibular inputs without integrating them. We have investigated the firing and biophysical properties of PHNn and developed data-based realistic neuronal models to quantitatively illustrate that their active conductances can produce the oscillatory behavior. Although some individual type D PHNn are able to show some features of mathematical integration, the lack of robustness of this behavior strongly suggests that additional network interactions, likely involving all types of PHNn, are essential for the neuronal integrator. Furthermore, the relationship between the impulse activity and membrane potential of type D PHNn is highly nonlinear and frequency-dependent, even for relatively small-amplitude responses. These results suggest that some of the synaptic input to type D PHNn is likely to evoke oscillatory responses that will be nonlinearly amplified as the spike discharge rate increases. It would appear that the PHNn have specific intrinsic properties that, in conjunction with network interconnections, enhance the persistent neural activity needed for their function.

Effects of toluene on tonic firing and membrane properties of rat medial vestibular nucleus neurones in vitro

1998 ◽  
Vol 779 (1-2) ◽  
pp. 334-337 ◽  
Author(s):  
Anna K Magnusson ◽  
M.Roslan Sulaiman ◽  
Mayank B Dutia ◽  
Richard Tham
Keyword(s):  
Vestibular Nucleus ◽  
Membrane Properties ◽  
Medial Vestibular Nucleus ◽  
Tonic Firing

Discharge patterns in nucleus prepositus hypoglossi and adjacent medial vestibular nucleus during horizontal eye movement in behaving macaques

1992 ◽  
Vol 68 (1) ◽  
pp. 319-332 ◽  
Author(s):  
J. L. McFarland ◽  
A. F. Fuchs
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Vestibular Nucleus ◽  
Medial Vestibular Nucleus ◽  
Eye Position ◽  
Head Velocity ◽  
Firing Rates ◽  
Prepositus Hypoglossi ◽  
Eye Velocity

1. Monkeys were trained to perform a variety of horizontal eye tracking tasks designed to reveal possible eye movement and vestibular sensitivities of neurons in the medulla. To test eye movement sensitivity, we required stationary monkeys to track a small spot that moved horizontally. To test vestibular sensitivity, we rotated the monkeys about a vertical axis and required them to fixate a target rotating with them to suppress the vestibuloocular reflex (VOR). 2. All of the 100 units described in our study were recorded from regions of the medulla that were prominently labeled after injections of horseradish peroxidase into the abducens nucleus. These regions include the nucleus prepositus hypoglossi (NPH), the medial vestibular nucleus (MVN), and their common border (the “marginal zone”). We report here the activities of three different types of neurons recorded in these regions. 3. Two types responded only during eye movements per se. Their firing rates increased with eye position; 86% had ipsilateral “on” directions. Almost three quarters (73%) of these medullary neurons exhibited a burst-tonic discharge pattern that is qualitatively similar to that of abducens motoneurons. There were, however, quantitative differences in that these medullary burst-position neurons were less sensitive to eye position than were abducens motoneurons and often did not pause completely for saccades in the off direction. The burst of medullary burst position neurons preceded the saccade by an average of 7.6 +/- 1.7 (SD) ms and, on average, lasted the duration of the saccade. The number of spikes in the burst was well correlated with saccade size. The second type of eye movement neuron displayed either no discernible burst or an inconsistent one for on-direction saccades and will be referred to as medullary position neurons. Neither the burst-position nor the position neurons responded when the animals suppressed the VOR; hence, they displayed no vestibular sensitivity. 4. The third type of neuron was sensitive to both eye movement and vestibular stimulation. These neurons increased their firing rates during horizontal head rotation and smooth pursuit eye movements in the same direction; most (76%) preferred ipsilateral head and eye movements. Their firing rates were approximately in phase with eye velocity during sinusoidal smooth pursuit and with head velocity during VOR suppression; on average, their eye velocity sensitivity was 50% greater than their vestibular sensitivity. Sixty percent of these eye/head velocity cells were also sensitive to eye position. 5. The NPH/MVN region contains many neurons that could provide an eye position signal to abducens neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

An in vitro investigation of the effects of the analogue, Org 2766, on guinea pig medial vestibular nucleus neurons

Peptides ◽  
1996 ◽  
Vol 17 (4) ◽  
pp. 681-688 ◽  
Author(s):  
Darrin P.D. Gilchrist ◽  
Cynthia L. Darlington ◽  
Paul F. Smith
Keyword(s):  
Guinea Pig ◽  
Vestibular Nucleus ◽  
Medial Vestibular Nucleus ◽  
In Vitro Investigation ◽  
Org 2766

Static and Dynamic Membrane Properties of Lateral Vestibular Nucleus Neurons in Guinea Pig Brain Stem Slices

2003 ◽  
Vol 90 (3) ◽  
pp. 1689-1703 ◽  
Author(s):  
Atsuhiko Uno ◽  
Erwin Idoux ◽  
Mathieu Beraneck ◽  
Pierre-Paul Vidal ◽  
Lee E. Moore ◽  
...  
Keyword(s):  
Vestibular Nucleus ◽  
Type A ◽  
Membrane Properties ◽  
In Vivo Studies ◽  
Medial Vestibular Nucleus ◽  
Intracellular Recordings ◽  
Lateral Vestibular Nucleus ◽  
Type B ◽  
Dynamic Membrane ◽  
Homogeneous Population

In vitro intracellular recordings of central vestibular neurons have been restricted so far to the medial vestibular nucleus (MVN). We performed intracellular recordings of large Deiters' neurons in the lateral vestibular nucleus (LVN) to determine their static and dynamic membrane properties, and compare them with those of type A and type B neurons identified in the MVN. Unlike MVN neurons (MVNn), the giant-size LVN neurons (LVNn) form a homogeneous population of cells characterized by sharp spikes, a low-amplitude, biphasic after-hyperpolarization like type B MVNn, but also an A-like rectification like type A MVNn. In accordance with their lower membrane resistance, the sensitivity of LVNn to current injection was lower than that of MVNn over a large range of frequencies. The main difference between LVNn and MVNn was that the Bode plots showing the sensitivity of LVNn as a function of stimulation frequency were flatter than those of MVNn, and displayed a weaker resonance. Furthermore, most LVNn did not show a gradual decrease of their firing rate modulation in the frequency range where it was observed in MVNn. LVNn synchronized their firing with the depolarizing phase of high-frequency sinusoidal current injections. In vivo studies have shown that the MVN would be mainly involved in gaze control, whereas the giant LVNn that project to the spinal cord are involved in the control of posture. We suggest that the difference in the membrane properties of LVNn and MVNn may reflect their specific physiological roles.

Histamine depolarizes rat medial vestibular nucleus neurons recorded intracellularly in vitro

1990 ◽  
Vol 109 (3) ◽  
pp. 287-292 ◽  
Author(s):  
Kevin D. Phelan ◽  
Jun Nakamura ◽  
Joel P. Gallagher
Keyword(s):  
Vestibular Nucleus ◽  
Medial Vestibular Nucleus

Long-Term Plasticity of Ipsilesional Medial Vestibular Nucleus Neurons After Unilateral Labyrinthectomy

2003 ◽  
Vol 90 (1) ◽  
pp. 184-203 ◽  
Author(s):  
Mathieu Beraneck ◽  
Mohammed Hachemaoui ◽  
Erwin Idoux ◽  
Laurence Ris ◽  
Atsuhiko Uno ◽  
...  
Keyword(s):  
Vestibular Nucleus ◽  
Type A ◽  
Vestibular Compensation ◽  
Membrane Properties ◽  
Medial Vestibular Nucleus ◽  
Type B ◽  
Dynamic Membrane ◽  
Vestibular Neurons ◽  
Unilateral Labyrinthectomy

Unilateral labyrinthectomy results in oculomotor and postural disturbances that regress in a few days during vestibular compensation. The long-term (after 1 mo) consequences of unilateral labyrinthectomy were investigated by characterizing the static and dynamic membrane properties of the ipsilesional vestibular neurons recorded intracellularly in guinea pig brain stem slices. We compared the responses of type A and type B medial vestibular nucleus neurons identified in vitro to current steps and ramps and to sinusoidal currents of various frequencies. All ipsilesional vestibular neurons were depolarized by 6–10 mV at rest compared with the cells recorded from control slices. Both their average membrane potential and firing threshold were more depolarized, which suggests that changes in active conductances compensated for the loss of excitatory afferents. The afterhyperpolarization and discharge regularity of type B but not type A neurons were increased. All ipsilesional vestibular cells became more sensitive to current injections over a large range of frequencies (0.2–30 Hz), but this increase in sensitivity was greater for type B than for type A neurons. This was associated with an increase of the peak frequency of linear response restricted to type B neurons, from 4–6 to 12–14 Hz. Altogether, we show that long-term vestibular compensation involves major changes in the membrane properties of vestibular neurons on the deafferented side. Many of the static and dynamic membrane properties of type B neurons became more similar to those of type A neurons than in control slices, leading to an increase in the overall homogeneity of medial vestibular nucleus neurons.

scholarly journals Postnatal Development of Spike Generation in Rat Medial Vestibular Nucleus Neurons

2001 ◽  
Vol 85 (5) ◽  
pp. 1899-1906 ◽  
Author(s):  
Gabe J. Murphy ◽  
Sascha Du Lac
Keyword(s):  
Firing Rate ◽  
Postnatal Development ◽  
Visual Function ◽  
Vestibular Nucleus ◽  
Image Motion ◽  
Membrane Properties ◽  
Medial Vestibular Nucleus ◽  
Spike Generation ◽  
Firing Rates ◽  
The Third

Image stability during self motion depends on the combined actions of the vestibuloocular and optokinetic reflexes (VOR and OKR, respectively). Neurons in the medial vestibular nucleus (MVN) participate in the VOR and OKR by firing in response to both head and image motion. Their intrinsic spike-generating properties enable MVN neurons to modulate firing rates linearly over a broad range of input amplitudes and frequencies such as those that occur during natural head and image motion. This study examines the postnatal development of the intrinsic spike-generating properties of rat MVN neurons with respect to maturation of peripheral vestibular and visual function. Spike generation was studied in a brain stem slice preparation by recording firing responses to current injected intracellularly through whole cell patch electrodes. MVN neurons fired spontaneously and modulated their firing rate in response to injected current at all postnatal ages. However, the input-output properties of the spike generator changed dramatically during the first two postnatal weeks. Neurons younger than postnatal day 10 could not fire faster than 80 spikes/s, modulated their firing rates over a limited range of input amplitudes, and tended to exhibit a nonlinear relationship between input current and mean evoked firing rate. In response to sustained depolarization, firing rates declined significantly in young neurons. Response gains tended to be highest in the first few postnatal days but varied widely across neurons and were not correlated with age. By about the beginning of the third postnatal week, MVN neurons could fire faster than 100 spikes/s in response to a broad range of input amplitudes, exhibited predominantly linear current-firing rate relationships, and adapted little in response to sustained depolarization. Concomitant decreases in action potential width and the time course of the afterhyperpolarization suggest that changes in potassium currents contribute to the maturation of the MVN neuronal spike generator. The results demonstrate that developmental changes in intrinsic membrane properties enable MVN neurons to fire linearly in response to a broad range of stimuli in time for the onset of visual function at the beginning of the third postnatal week.

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