Contribution of vestibular nerve irregular afferents to viewing distance-related changes in the vestibulo-ocular reflex

Chen-Huang, Chiju; McCrea, R. A.

doi:10.1007/s002210050325

Cited by 33 publications

(40 citation statements)

References 18 publications

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“…In primates, these afferents have been shown to provide the major inputs to vestibulospinal pathways (Boyle et al, 1992). Irregular afferents also appear to be important for vergence-mediated changes in the vestibuloocular reflex (Chen-Huang and McCrea, 1998; Lasker et al, 2002; Migliaccio et al, 2008). Unless there are reciprocal temperature-dependent changes in the sensitivity to motion of central neurons, then responses of central processes and reflexes receiving irregular afferent inputs would be expected to decline as temperature falls.…”

Section: Discussionmentioning

confidence: 99%

Static and dynamic discharge properties of vestibular-nerve afferents in the mouse are affected by core body temperature

2009

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The goal of this study was to determine the effect of changes in core body temperature on the resting discharge rate and sensitivity of vestibular-nerve afferents. Extracellular recordings were made from vestibular-nerve afferents innervating the semicircular canals in anesthetized C57BL/6 mice maintained at a core body temperature of either 30 – 32° (T31) or 35 – 37° (T36) C. The resting rates of regular (CV* < 0.1) and irregular afferents (CV* > 0.1) were lower at T31 than at T36. Sensitivity and phase were compared for rotations ranging from 0.1 – 12 Hz by calculating coefficients of a transfer function, g·tc1s·(tzs + 1)/(tc1s + 1), for each afferent. The sensitivity (g) increased with CV* and with higher core body temperature. The value of the coefficient representing the low-frequency dynamics (tc1) varied inversely with CV* but did not change with core body temperature. The high-frequency dynamics represented by tz increased with CV* and decreased with higher core body temperature. These findings indicate that changes in temperature have effects on the static and dynamic properties of vestibular-nerve afferents.

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Section: Discussionmentioning

confidence: 99%

Static and dynamic discharge properties of vestibular-nerve afferents in the mouse are affected by core body temperature

2009

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“…As is almost always the case with ablation paradigms, such "negative" results are easier to interpret than are "positive" results. In particular, it cannot be concluded that a response diminished by the currents necessarily depends on irregular afferents (Chen-Huang et al 1997;Chen-Huang and McCrea 1998). This is because most responses involve polysynaptic pathways, which can carry regular, irregular, or mixed signals.…”

Section: Functional Ablation Of Irregular Afferentsmentioning

confidence: 91%

“…On the other hand, studies of the effects of the ablating currents on the linear VOR (LVOR) have produced inconsistent results. Chen-Huang and McCrea (1998) studied the eye movements produced during eccentric whole-body rotations, which include both AVOR and LVOR components. They reported that the ablating currents had only small effects and that these could be attributed to changes in the AVOR component.…”

Section: Functional Ablation Of Irregular Afferentsmentioning

confidence: 99%

Afferent diversity and the organization of central vestibular pathways

2000

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This review considers whether the vestibular system includes separate populations of sensory axons innervating individual organs and giving rise to distinct central pathways. There is a variability in the discharge properties of afferents supplying each organ. Discharge regularity provides a marker for this diversity since fibers which differ in this way also differ in many other properties. Postspike recovery of excitability determines the discharge regularity of an afferent and its sensitivity to depolarizing inputs. Sensitivity is small in regularly discharging afferents and large in irregularly discharging afferents. The enhanced sensitivity of irregular fibers explains their larger responses to sensory inputs, to efferent activation, and to externally applied galvanic currents, but not their distinctive response dynamics. Morphophysiological studies show that regular and irregular afferents innervate overlapping regions of the vestibular nuclei. Intracellular recordings of EPSPs reveal that some secondary vestibular neurons receive a restricted input from regular or irregular afferents, but that most such neurons receive a mixed input from both kinds of afferents. Anodal currents delivered to the labyrinth can result in a selective and reversible silencing of irregular afferents. Such a functional ablation can provide estimates of the relative contributions of regular and irregular inputs to a central neuron's discharge. From such estimates it is concluded that secondary neurons need not resemble their afferent inputs in discharge regularity or response dynamics. Several suggestions are made as to the potentially distinctive contributions made by regular and irregular afferents: (1) Reflecting their response dynamics, regular and irregular afferents could compensate for differences in the dynamic loads of various reflexes or of individual reflexes in different parts of their frequency range; (2) The gating of irregular inputs to secondary VOR neurons could modify the operation of reflexes under varying behavioral circumstances; (3) Two-dimensional sensitivity can arise from the convergence onto secondary neurons of otolith inputs differing in their directional properties and response dynamics; (4) Calyx afferents have relatively low gains when compared with irregular dimorphic afferents. This could serve to expand the stimulus range over which the response of calyx afferents remains linear, while at the same time preserving the other features peculiar to irregular afferents. Among those features are phasic response dynamics and large responses to efferent activation; (5) Because of the convergence of several afferents onto each secondary neuron, information transmission to the latter depends on the gain of individual afferents, but not on their discharge regularity.

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“…Other vestibular nuclei neurons project to the ipsilateral or contralateral vestibular nuclei (Malinvaud et al, 2010), nucleus prepositus hypoglossi (McCrea and Baker, 1985; Kolkman et al, 2011), cerebellar flocculus (Highstein and Holstein, 2006), parabrachial nucleus (McCandless and Balaban, 2010), or to multiple brainstem nuclei regulating sympathetic outflow (Holstein et al, 2011). Still other vestibular nuclei neurons function as local circuit interneurons (Highstein and Holstein, 2006; Popratiloff and Peusner, 2011), or participate in the polysynaptic VOR pathways (Chen-Huang and McCrea, 1998). …”

Section: Structure/function Studies On the Vestibular Nuclear Complexmentioning

confidence: 99%

Basic Concepts in Understanding Recovery of Function in Vestibular Reflex Networks during Vestibular Compensation

Peusner¹,

Shao²,

Reddaway³

et al. 2012

Front. Neur.

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Unilateral peripheral vestibular lesions produce a syndrome of oculomotor and postural deficits with the symptoms at rest, the static symptoms, partially or completely normalizing shortly after the lesion due to a process known as vestibular compensation. The symptoms are thought to result from changes in the activity of vestibular sensorimotor reflexes. Since the vestibular nuclei must be intact for recovery to occur, many investigations have focused on studying these neurons after lesions. At present, the neuronal plasticity underlying early recovery from the static symptoms is not fully understood. Here we propose that knowledge of the reflex identity and input–output connections of the recorded neurons is essential to link the responses to animal behavior. We further propose that the cellular mechanisms underlying vestibular compensation can be sorted out by characterizing the synaptic responses and time course for change in morphologically defined subsets of vestibular reflex projection neurons. Accordingly, this review focuses on the perspective gained by performing electrophysiological and immunolabeling studies on a specific subset of morphologically defined, glutamatergic vestibular reflex projection neurons, the principal cells of the chick tangential nucleus. Reference is made to pertinent findings from other studies on vestibular nuclei neurons, but no comprehensive review of the literature is intended since broad reviews already exist. From recording excitatory and inhibitory spontaneous synaptic activity in principal cells, we find that the rebalancing of excitatory synaptic drive bilaterally is essential for vestibular compensation to proceed. This work is important for it defines for the first time the excitatory and inhibitory nature of the changing synaptic inputs and the time course for changes in a morphologically defined subset of vestibular reflex projection neurons during early stages of vestibular compensation.

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Contribution of vestibular nerve irregular afferents to viewing distance-related changes in the vestibulo-ocular reflex

Cited by 33 publications

References 18 publications

Static and dynamic discharge properties of vestibular-nerve afferents in the mouse are affected by core body temperature

Static and dynamic discharge properties of vestibular-nerve afferents in the mouse are affected by core body temperature

Afferent diversity and the organization of central vestibular pathways

Basic Concepts in Understanding Recovery of Function in Vestibular Reflex Networks during Vestibular Compensation

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