Cochlear Implantation ; Humans ; Vestibule, Labyrinth ; physiology

This review focuses on our effort in addressing the development and lesion-induced plasticity of the gravity sensing system. After severance of sensory input from one inner ear, there is a bilateral imbalance in response dynamics and spatial coding behavior between neuronal subpopulations on the two sides. These data provide the basis for deranged spatial coding and motor deficits accompanying unilateral labyrinthectomy. Recent studies have also confirmed that both glutamate receptors and neurotrophin receptors within the bilateral vestibular nuclei are implicated in the plasticity during vestibular compensation and development. Changes in plasticity not only provide insight into the formation of a spatial map and recovery of vestibular function but also on the design of drugs for therapeutic strategies applicable to infants or vestibular disorders such as vertigo and dizziness.
Animals ; Humans ; Neuronal Plasticity ; Neurons ; physiology ; Otolithic Membrane ; innervation ; physiology ; Vestibule, Labyrinth ; innervation ; physiology

OBJECTIVETo explore the normal values of vestibular autorotation test (VAT) in young people.

METHODSVAT was performed in 31 young people aged 20-30 years. The measured value were analyzed and compared with the reference normal value.

RESULTSThe measured values of VAT in healthy young people are almost within the normal range of the general population. Compared with the reference normal values, the horizontal gains at 2.0, 2.3, 2.7, 5.5, and 5.9 Hz, the vertical gains at 2.0 and 5.9 Hz, and the vertical phases at 2.0, 2.3, 2.7, 3.1, 3.5, and 3.9 Hz were significantly different (P < 0. 05). No significant difference was shown in the horizontal phases and asymmetry.

CONCLUSIONSThe normal values of VAT in young people is within the reference normal range of the general population. The vestibular function of young people may be more sensitive in lower frequency range (2-3Hz).

Adult ; Female ; Humans ; Male ; Reference Values ; Vestibular Function Tests ; standards ; Vestibule, Labyrinth ; chemistry ; physiology ; Young Adult

Vestibular compensation is an important model for developing the prevention and intervention strategies of vestibular disorders, and investigating the plasticity of the adult central nervous system induced by peripheral injury. Medial vestibular nucleus (MVN) in brainstem is critical center for vestibular compensation. Its neuronal excitability and sensitivity have been implicated in normal function of vestibular system. Previous studies mainly focused on the changes in neuronal excitability of the MVN in lesional side of the rat model of vestibular compensation following the unilateral labyrinthectomy (UL). However, the plasticity of sensitivity of bilateral MVN neurons dynamically responding to input stimuli is still largely unknown. In the present study, by using qPCR, whole-cell patch clamp recording in acute brain slices and behavioral techniques, we observed that 6 h after UL, rats showed a significant deficit in spontaneous locomotion, and a decrease in excitability of type B neurons in the ipsilesional rather than contralesional MVN. By contrast, type B neurons in the contralesional rather than ipsilesional MVN exhibited an increase in response sensitivity to the ramp and step input current stimuli. One week after UL, both the neuronal excitability of the ipsilesional MVN and the neuronal sensitivity of the contralesional MVN recovered to the baseline, accompanied by a compensation of spontaneous locomotion. In addition, the data showed that the small conductance Ca²⁺-activated K⁺ (SK) channel involved in the regulation of type B MVN neuronal sensitivity, showed a selective decrease in expression in the contralesional MVN 6 h after UL, and returned to normal level 1 week later. Pharmacological blockage of SK channel in contralateral MVN to inhibit the UL-induced functional plasticity of SK channel significantly delayed the compensation of vestibular motor dysfunction. These results suggest that the changes in plasticity of the ipsilesional MVN neuronal excitability, together with changes in the contralesional MVN neuronal sensitivity, may both contribute to the development of vestibular symptoms as well as vestibular compensation, and SK channel may be an essential ionic mechanism responsible for the dynamic changes of MVN neuronal sensitivity during vestibular compensation.
Animals ; Locomotion ; Neurons/physiology* ; Patch-Clamp Techniques ; Rats ; Vestibular Nuclei/metabolism* ; Vestibule, Labyrinth

Accurate self-motion perception, which is critical for organisms to survive, is a process involving multiple sensory cues. The two most powerful cues are visual (optic flow) and vestibular (inertial motion). Psychophysical studies have indicated that humans and nonhuman primates integrate the two cues to improve the estimation of self-motion direction, often in a statistically Bayesian-optimal way. In the last decade, single-unit recordings in awake, behaving animals have provided valuable neurophysiological data with a high spatial and temporal resolution, giving insight into possible neural mechanisms underlying multisensory self-motion perception. Here, we review these findings, along with new evidence from the most recent studies focusing on the temporal dynamics of signals in different modalities. We show that, in light of new data, conventional thoughts about the cortical mechanisms underlying visuo-vestibular integration for linear self-motion are challenged. We propose that different temporal component signals may mediate different functions, a possibility that requires future studies.
Animals ; Humans ; Motion Perception/physiology* ; Bayes Theorem ; Optic Flow ; Cues ; Vestibule, Labyrinth/physiology* ; Photic Stimulation ; Visual Perception/physiology*

OBJECTIVE: To observe waveform difference among cervical vestibular evoked myogenic potentials (cVEMP) elicited with different types of air conducted sound in normal young Chinese subjects. METHOD: Twenty adult volunteers (40 ears) were recruited as research subjects including 10 males and 10 females aged between 19 and 30.500 Hz Tone Burst, 1000 Hz Tone Burst and Click were employed as stimulus for conventional air conducted sound-cVEMP (ACS-cVEMP) examinations in bilateral ears of each subject. The response rate, threshold, P1 latency, N1 latency, P1-N1 latency interval, amplitude and inter-aural asymmetry were recorded and compared among groups. RESULT: The response rate was 97.5% in 500Hz Tone Burst (39/40), 87.5% in 1 000Hz Tone Burst (35/40)and 67.5% in Click (27/40), There were no statistically significant difference between 500Hz Tone Burst and 1000Hz Tone Burst (P > 0.05) but there were statistically significant difference between click and the other groups (P < 0.05). We collected the waveform parameters (the threshold, P1 latency, N1 latency, P1-N1 latency interval, amplitude) which had statistically significant difference between 500 Hz Tone Burst and the other groups (P < 0.05). The inter-aural asymmetrys had no statistically significant differents among groups. CONCLUSION The response rate and parameter could be affected by different types of air conducted sound in normal young Chinese subjects. 500 Hz Tone Burst was the best stimulus of type what we have known.
Adult ; Asian Continental Ancestry Group ; Female ; Humans ; Male ; Neck ; Vestibular Evoked Myogenic Potentials ; Vestibule, Labyrinth ; physiology ; Young Adult

OBJECTIVETo study the mechanism of vestibular compensation and to observe the changes of c-Fos and NADPH-d expressions in the brainstem of the vestibular deafferentation rats in static status or following angular acceleration stimulation.

METHODSTotally 60 SD rats were randomly divided into control group (labyrinthine intact), complete unilateral vestibular deafferentation (UVD) group, simultaneous complete bilateral vestibular deafferentation (BVD) group (n = 20 in each group). Subgroups (n = 10 in each subgroup) were set for static status or following angular acceleration stimulation in each group. Double labeling with histochemistry-immunohistochemistry was performed to observe c-Fos/NADPH-d neurons.

RESULTSNo positive c-Fos/NADPH-d expression was observed in the both sides of medial vestibular nucleus (MVN) and prepositus hypoglossi (PrH) of normal rats in static status and BVD rats whether following canal rotation or not. c-Fos/ NADPH-d expression was observed in the ipsilesional MVN and the contralesional PrH of UVD rats. However, c-Fos/NADPH-d were detected in both sides of MVN and PrH in UVD rats and normal rats following angular acceleration stimulation.

CONCLUSIONIn the ipsilesional MVN and the contralesional PrH, c-Fos plays an important role in vestibular compensation, in which nitric oxide acts as a key neurotransmitter.

Animals ; Brain Stem ; metabolism ; Dihydrolipoamide Dehydrogenase ; genetics ; metabolism ; Female ; Gene Expression ; Male ; Proto-Oncogene Proteins c-fos ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Vestibule, Labyrinth ; physiology

OBJECTIVE: To investigate the correlation between the polymorphism of genotype of site-1296 in alpha2A-AR receptor gene and the susceptibility of vestibular function. METHOD: Ninety-four blood samples were collected from pilot cadets, consisting of susceptible and tolerance groups to vestibular function. Genomic DNA was isolated, and the coding region of alpha2A-AR receptor gene was amplified by polymerase chain reaction (PCR). The PCR products were analyzed by gene sequencing. Gene frequency was calculated, and, the coincidence between the polymorphism of alpha2A-AR receptor gene in the groups and Hardy-Weinberg balance was evaluated. The allele frequency of the two groups was compared by Chi square test. RESULT: G/C polymorphism was existed in Site-1296 of alpha2A-AR gene regulation zone, including GG, GC, CC. The express of GG Genotype in susceptible group exceeded that of the other group. There were significance differences in both genotype constituent ratio and alleles frequency of the two groups. CONCLUSION The polymorphism of genotype of site-1296 in alpha2A-AR receptor gene is possibly correlated with the susceptibility to vestibular function.
Adult ; Alleles ; Gene Frequency ; Genotype ; Humans ; Male ; Polymorphism, Single Nucleotide ; Receptors, Adrenergic, alpha-2 ; genetics ; Vestibular Function Tests ; Vestibule, Labyrinth ; physiology ; Young Adult

Bone morphogenetic proteins (BMPs) are the largest subfamily of the transforming growth factor-β superfamily, and they play important roles in the development of numerous organs, including the inner ear. The inner ear is a relatively small organ but has a highly complex structure and is involved in both hearing and balance. Here, we discuss BMPs and BMP signaling pathways and then focus on the role of BMP signal pathway regulation in the development of the inner ear and the implications this has for the treatment of human hearing loss and balance dysfunction.
Body Patterning ; Bone Morphogenetic Protein Receptors/physiology* ; Bone Morphogenetic Proteins/physiology* ; Cell Differentiation ; Cochlea/embryology* ; Ear, Inner/embryology* ; Hedgehog Proteins/physiology* ; Humans ; Signal Transduction/physiology* ; Smad Proteins/physiology* ; Vestibule, Labyrinth/embryology* ; Wnt Signaling Pathway