In vivo recording of the vestibular microphonic in mammals

Pastras, Christopher J.; Curthoys, Ian S.; Brown, Daniel

doi:10.1016/j.heares.2017.07.015

Cited by 21 publications

(24 citation statements)

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“…Most importantly, in these animals, the cochlea has been completely removed, so there is no contribution from the cochlear microphonic. The recent paper ( 57 ) gives the evidence that the vestibular microphonic is a field potential due to otolithic receptor hair cell activation—reporting all the correct controls—such as chemically silencing afferent neurons and showing that the vestibular microphonic remains, and conversely chemically silencing the receptors and showing that the vestibular microphonic disappears, leading to the conclusion that the vestibular microphonic is a field potential generated by otolithic hair cells (utricular hair cells in this case) (Figure 5 ). The vestibular microphonic (strictly the utricular microphonic) has been recorded up to frequencies of 3,000 Hz.…”

Section: Phase Lockingmentioning

confidence: 95%

“…How can such an apparently sluggish system as the otoliths with such dense otoconia exhibit phase locking to stimulus frequencies of thousands of Hertz? One answer comes from recording the vestibular microphonic, which shows that mammalian utricular receptors are activated at such high frequencies ( 57 , 58 ). The vestibular microphonic is a field potential to sound or vibration and is a direct electrophysiological indicator of otolithic receptor hair cell function.…”

Section: Phase Lockingmentioning

confidence: 99%

“…The vestibular microphonic is a field potential to sound or vibration and is a direct electrophysiological indicator of otolithic receptor hair cell function. The vestibular microphonic has been recorded in vivo in anesthetized guinea pigs by electrodes piercing the underside of the utricular macula with a glass microelectrode and then measuring the vestibular microphonic to BCV or ACS stimuli of varying frequency and amplitude (Figure 5 ) ( 57 ). Most importantly, in these animals, the cochlea has been completely removed, so there is no contribution from the cochlear microphonic.…”

Section: Phase Lockingmentioning

confidence: 99%

“…Panel (C) shows the simultaneous measurement of vestibular microphonic and macula velocity. (B) Reprinted from Pastras et al ( 57 ), © 2017, with permission from Elsevier. Panel (C) is from Pastras et al ( 59 ).…”

Section: Phase Lockingmentioning

confidence: 99%

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Otolithic Receptor Mechanisms for Vestibular-Evoked Myogenic Potentials: A Review

et al. 2018

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Air-conducted sound and bone-conduced vibration activate otolithic receptors and afferent neurons in both the utricular and saccular maculae, and trigger small electromyographic (EMG) responses [called vestibular-evoked myogenic potentials (VEMPs)] in various muscle groups throughout the body. The use of these VEMPs for clinical assessment of human otolithic function is built on the following logical steps: (1) that high-frequency sound and vibration at clinically effective stimulus levels activate otolithic receptors and afferents, rather than semicircular canal afferents, (2) that there is differential anatomical projection of otolith afferents to eye muscles and neck muscles, and (3) that isolated stimulation of the utricular macula induces short latency responses in eye muscles, and that isolated stimulation of the saccular macula induces short latency responses in neck motoneurons. Evidence supports these logical steps, and so VEMPs are increasingly being used for clinical assessment of otolith function, even differential evaluation of utricular and saccular function. The proposal, originally put forward by Curthoys in 2010, is now accepted: that the ocular vestibular-evoked myogenic potential reflects predominantly contralateral utricular function and the cervical vestibular-evoked myogenic potential reflects predominantly ipsilateral saccular function. So VEMPs can provide differential tests of utricular and saccular function, not because of stimulus selectivity for either of the two maculae, but by measuring responses which are predominantly determined by the differential neural projection of utricular as opposed to saccular neural information to various muscle groups. The major question which this review addresses is how the otolithic sensory system, with such a high density otoconial layer, can be activated by individual cycles of sound and vibration and show such tight locking of the timing of action potentials of single primary otolithic afferents to a particular phase angle of the stimulus cycle even at frequencies far above 1,000 Hz. The new explanation is that it is due to the otoliths acting as seismometers at high frequencies and accelerometers at low frequencies. VEMPs are an otolith-dominated response, but in a particular clinical condition, semicircular canal dehiscence, semicircular canal receptors are also activated by sound and vibration, and act to enhance the otolith-dominated VEMP responses.

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Section: Phase Lockingmentioning

confidence: 95%

Section: Phase Lockingmentioning

confidence: 99%

Section: Phase Lockingmentioning

confidence: 99%

Section: Phase Lockingmentioning

confidence: 99%

See 2 more Smart Citations

Otolithic Receptor Mechanisms for Vestibular-Evoked Myogenic Potentials: A Review

et al. 2018

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show abstract

“…Experimental evidence for the "seismometer" mode of otolith organs derives from a sophisticated guinea pig model showing that application of sound or vibration to the guinea pig's skull resulted in periodic oscillations of the utricular macula and de-/repolarizations of the utricular hair cells in sync with the stimulus frequency up to several kHz (for details see S3 [online supplementary material] and [65,66]).…”

Section: Biomechanical Evidencementioning

confidence: 99%