Horizontal Vestibuloocular Reflex Evoked by High-Acceleration Rotations in the Squirrel Monkey. I. Normal Responses

Minor, Lloyd B.; Lasker, David M.; Backous, Douglas D.; Hullar, Timothy E.

doi:10.1152/jn.1999.82.3.1254

Cited by 166 publications

(151 citation statements)

References 45 publications

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“…In accordance with the model put forward by Minor et al (1999) for the monkey HVOR, we have suggested (Ris et al 2001b) that at high frequencies, type B MVNn might work in a nonlinear way, such as a signal detection mode, to amplify the contribution of vestibular nerve afferents. This should apply to guinea pigs because the HVOR dynamics and the way they are affected by UL appear roughly similar in all mammalian species Escudero et al 1993;Gilchrist et al 1998;Minor et al 1999;Smith and Curthoys 1989). Because our sinusoidal stimulations were designed to evoke only linear responses, the decrease of the firing rate modulation displayed by type B MVNn Ͼ4 Hz might result from the progressive involvement of nonlinear properties in the responses of type B MVNn at higher frequencies.…”

Section: Functional Implications Of the Long-term Changes Of The Membsupporting

confidence: 73%

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

Beraneck

Hachemaoui²,

Idoux³

et al. 2003

Journal of Neurophysiology

109

142

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. Long-term plasticity of ipsilesional medial vestibular nucleus neurons after unilateral labyrinthectomy. J Neurophysiol 90: 184 -203, 2003. First published March 20, 2003 10.1152/jn.01140.2002. 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.

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Section: Functional Implications Of the Long-term Changes Of The Membsupporting

confidence: 73%

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

Beraneck

Hachemaoui²,

Idoux³

et al. 2003

Journal of Neurophysiology

109

142

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“…Another difference in our study is we report VOR gain during the acceleration and constant velocity components of a step rotation. This is based on prior work in our laboratory, which has shown behavioral differentiation within the VOR pathway based on the acceleration (phasic component of the VOR which is accentuated at higher frequencies) and velocity (tonic component) content of the head motion (Minor et al 1999). We conducted VOR behavioral studies in squirrel monkeys and established that the phasic component of the VOR is larger during acceleration steps (G A ) than during constant velocity (G V ) rotation (Minor et al 1999).…”

Section: Introductionmentioning

confidence: 99%

“…This is based on prior work in our laboratory, which has shown behavioral differentiation within the VOR pathway based on the acceleration (phasic component of the VOR which is accentuated at higher frequencies) and velocity (tonic component) content of the head motion (Minor et al 1999). We conducted VOR behavioral studies in squirrel monkeys and established that the phasic component of the VOR is larger during acceleration steps (G A ) than during constant velocity (G V ) rotation (Minor et al 1999). Clendaniel et al (2002) showed that the two components of the VOR pathway can be selectively modified by altering the frequency and velocity content of the adapting stimulus.…”

Section: Introductionmentioning

confidence: 99%

Retention of VOR gain following short-term VOR adaptation

et al. 2008

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Motor learning in the vestibular system can be differentially obtained depending upon the context for which the vestibulo-ocular reflex (VOR) has been exposed. Manipulating head orientation relative to gravity is an example of a contextual cue that can elicit independent VOR gains. We were interested in examining retention of short-term VOR adaptation when the adapting stimulus was paired with a novel contextual cue. Two sets of non-human primate VOR adaptation experiments were designed to assess the influence of head position relative to gravity on retention of the pitch VOR. First, the pitch VOR of three squirrel monkeys was adapted for 3 h using minimizing (×0.45) spectacles and a sum-of-sines stimulus (20°/s at 0.5, 1.1, 2.3, and 3.7 Hz) while the animals were positioned left ear down (LED adaptation). Pitch VOR gains were measured in the adapted position (LED) and two non-adapted positions (upright, UP) or right ear down (RED). In the second set of experiments, the pitch VOR was adapted in an upright head position (same adapting stimulus as used in LED) and tested in UP, LED or RED. No head immobility or darkness restrictions were imposed on the animals after the initial adaptation exposure. The pitch VOR gains were measured during the acceleration (G A ) and constant velocity (G V ) portions of 1,000°/s 2 −150°/s step responses and during 0.5, 2.0, and 4.0 Hz sinusoids with velocities varying from 20 to 100°/s. All measures of VOR gain for UP, LED, and RED were done immediately after the adaptation and for three subsequent days and at postadaptation day 7 (PAD 7). When tested in the adapting position, all experiments showed immediate reduction in G A and G V compared with pre-adaptation levels. For LED adaptation experiments, the pitch G A and G V gains were significantly reduced for as long as 7 days. Some retention of the LEDadapted VOR gain also occurred when testing in the RED position. No retention of pitch VOR G A or G V existed for the UP position after adaptation in LED. After the UP-adapt experiments, no retention of the G A or G V was found when tested in the adapting position. Interestingly, however, some retention of G A and G V did exist when the UP-adapted animals were tested in LED or RED. Data from sinusoidal rotations followed a similar adaptation pattern as the step responses. Our Correspondence to: Michael C. Schubert, mschube1@jhmi.edu. findings show that after only 3 h of adaptation exposure, adaptation of the pitch VOR gain is retained for several days. This long-term retention of VOR adaptation after short-term exposure appears to be the result of inducing adaptation with an atypical combination of movement and position for the monkey (LED-adapt). Our results indicate that head orientation relative to gravity is an effective context for retaining learned VOR gains in addition to restricting mobility or keeping animals in the dark. We also show that the adapting head position determines the magnitude of VOR adaptation. NIH Public Access

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“…The gain and phase of the VOR in the light (VORl) and dark (VORd) have been well characterized for a range of head-perturbation frequencies in humans and non-human primates (e.g., Barr et al 1976;Correia et al 1985;Das et al 1998;Minor et al 1999;Paige 1983). These studies have shown that the gain of the VOR is higher when viewing a stationary target in the light than when imagining a target in complete darkness, suggesting cooperation between the VOR and visually mediated eye movements.…”

Section: Introductionmentioning

confidence: 99%

Role of the Dorsolateral Pontine Nucleus in Short-Term Adaptation of the Horizontal Vestibuloocular Reflex

Ono¹,

Das

Mustari

2003

Journal of Neurophysiology

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Ono, Seiji, V. E. Das, and M. J. Mustari. Role of the dorsolateral pontine nucleus in short-term adaptation of the horizontal vestibuloocular reflex. J Neurophysiol 89: 2879 -2885, 2003; 10.1152/jn.00602.2002. The dorsolateral pontine nucleus (DLPN) is a major component of the cortico-ponto-cerebellar pathway that carries signals essential for smooth pursuit. This pathway also carries visual signals that could play a role in visually guided motor learning in the vestibular ocular reflex (VOR). However, there have been no previous studies that tested this possibility directly. The aim of this study was to determine the potential role of the DLPN in short-term VOR gain adaptation produced by viewing a scene through lenses placed in front of both eyes. In control experiments, adaptation of VOR gain was achieved by sinusoidal rotation (0.2 Hz, 30°/s) for 2 h while the monkey viewed a stationary visual surround through either magnifying (ϫ2) or minifying (ϫ0.5) lenses. This led to increases (23-32%) or decreases (22-48%) of VOR gain as measured in complete darkness (VORd). We used injections of muscimol, a potent GABA A agonist (0.5 l; 2%), to reversibly inactivate the DLPN, unilaterally, in three monkeys. After DLPN inactivation, initial acceleration of ipsilateral smoothpursuit was reduced by 35-68%, and steady-state gain was reduced by 32-61%. Despite these significant deficits (P Ͻ 0.01) in ipsilesional smooth pursuit, the VOR during lens viewing was similar to that measured in preinjection control experiments. Similarly, after 2 h of adaptation, VORd gain was not significantly different (P Ͼ 0.61) from control adaptation values for either ipsi-or contralesional directions of head rotation. This was the case even though a stable ipsilesional smooth pursuit deficit persisted throughout the full adaptation period. Our results suggest that visual error signals for short-term adaptation of the VOR are derived from sources other than the DLPN perhaps including other basilar pontine nuclei and the accessory optic system.

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Horizontal Vestibuloocular Reflex Evoked by High-Acceleration Rotations in the Squirrel Monkey. I. Normal Responses

Cited by 166 publications

References 45 publications

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

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

Retention of VOR gain following short-term VOR adaptation

Role of the Dorsolateral Pontine Nucleus in Short-Term Adaptation of the Horizontal Vestibuloocular Reflex

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