The inner ear houses both hearing and balance sensory modalities. organs consist of similar cell types, including hair cells associated supporting cells. Previously we showed that Notch1 is required for maintaining survival during cochlear maturation. To understand the role Notch vestibular maturation, deleted from male female mice at birth. Histological analyses a reduction accompanied by an increase in type II cells, indicating conversion to Analysis mature indicate converted survive,...

We hypothesized that active outer hair cells drive cochlear fluid circulation. The hypothesis was tested by delivering the neurotoxin, kainic acid, to intact round window of young gerbil cochleae while monitoring auditory responses in nucleus. Sounds presented at a modest level significantly expedited acid delivery. When outer-hair-cell motility suppressed salicylate, facilitation effect compromised. A low-frequency tone more effective than broadband noise, especially for drug delivery...

Migraine is a severe and chronic neurological disorder that affects ~18% of people worldwide, the majority being female (3:1). It characterized by recurrent, debilitating headaches heightened sensory sensitivities. People with migraine may develop vestibular (VM), motion sensitivity preponderance for spontaneous vertigo attacks balance problems such as postural instability. Calcitonin gene-related peptide (CGRP) implicated in believed to act on brain meninges or subcortical central nervous...

The precise role and mechanisms underlying efferent modulation of peripheral vestibular afferent function are not well understood in mammals. Clarifying the details action may lead to new strategies for clinical management debilitating disturbances balance function. Recent evidence turtle indicates that M-currents is likely one mechanism modifying discharge. depend part on KCNQ potassium conductances (Kv7), which can be adjusted through activation M1, M3, and/or M5 muscarinic acetylcholine...

The injectable anesthetic mixture ketamine-xylazine is commonly used for electrophysiologic experiments in laboratory animals, especially rodents.General anesthesia can induce significant changes systemic physiology, including those that compromise neural function, thus introducing research confounds.The extent of such concerns varies by agent.Here mice, we compared the effects and urethane-xylazine on physiologic parameters vestibular sensory evoked potential (VsEP), a tool to assess...

Electrical stimulation of the mammalian efferent vestibular system (EVS) predominantly excites primary afferents along two distinct time scales. Although roles for acetylcholine (ACh) have been demonstrated in other vertebrates, synaptic mechanisms underlying EVS actions are not well-characterized. To determine if activation ACh receptors account efferent-mediated afferent excitation mammals, we recorded activity from superior nerve anesthetized C57BL/6 mice while stimulating neurons...

Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied AN CAPs 2- 16-kHz tone bursts at several sound levels slowly injecting kainic acid solution into cochlear apex anesthetized guinea pigs. As flowed from base, it sequentially reduced CAP responses low- high-frequency regions. The times which were reduced, combined with location traversed that time, showed origin removed component. For low-level...

Objective This study examined the clinical use of computerized gaze stabilization test (GST) as a screener for falls. Design Cross-sectional, descriptive. Setting Tertiary medical center. Subjects Fifteen older community-dwelling adults with history falls and 15 controls without were recruited participation in study. Main Outcome Measures Participants performed GST yaw plane head movements. The velocity was measured compared dynamic gait index (DGI). Receiver operating characteristic (ROC)...

Electrocochleography (ECochG) has been used to assess Ménière's disease, a pathology associated with endolymphatic hydrops and low-frequency sensorineural hearing loss. However, the current ECochG techniques are limited for use at high-frequencies only (≥ 1 kHz) cannot be understand loss in ears disease. In study, we relatively new technique make measurements that originate from afferent auditory nerve fibers apical half of cochlear spiral effects guinea pig ears. These made Auditory Nerve...

Background: The vestibular sensory-evoked potential (VsEP) is an electrical that provides a direct test of function in animals. VsEP recordings are carried out using subcutaneous stainless steel electrodes placed over the nuchal crest (noninverting), behind either left or right pinna (inverting), and at hip (ground). A noninvasive head clip used to secure mechanical shaker for delivery linear stimulus measured units jerk (g/msec). Frequent repositioning skin may be necessary during recording...

Abstract The inner ear houses two sensory modalities: the hearing organ, located in cochlea, and balance organs, throughout vestibular regions of ear. Both are composed similar cell types, including hair cells associated supporting cells. Recently, we showed that Notch1 is required for maintaining survival postnatally during cochlear maturation. However, it not known whether plays a role organs To characterize Notch maturation, conditionally deleted from Sox2 -expressing mouse at P0/P1....

We hypothesized that active outer hair cells drive cochlear fluid circulation. The hypothesis was tested by delivering the neurotoxin, kainic acid, to intact round window of young gerbil cochleae while monitoring auditory responses in nucleus. Sounds presented at a modest level significantly expedited acid delivery. When outer-hair-cell motility suppressed salicylate, facilitation effect compromised. A low-frequency tone more effective than broadband noise, especially for drug delivery...

Hearing depends on glutamatergic synaptic transmission mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). AMPARs are tetramers, where inclusion of the GluA2 subunit reduces overall channel conductance and Ca2+ permeability. Cochlear afferent synapses between inner hair cells (IHCs) auditory nerve fibers (ANFs) contain AMPAR subunits GluA2, 3, 4. However, tetrameric complement cochlear is not known. It was recently shown in mice that chronic intracochlear...

The gaze stabilization test (GST) is used not only in examining stability required by daily life activities, but also identifying unilateral or bilateral vestibular deficits. However, a computerized GST (CGST) an expensive assessment, which cannot be commonly most clinics. Validation of low-cost and low-technical clinical tests to decrease health care costs. purpose this study was measure the accuracy new (NGST) cohort healthy young adults with no history balance disorders, as well...

Endolymphatic hydrops is an enlargement of scala media that most often associated with Meniere's disease, though the pathophysiologic mechanism(s) remain unclear. In order to adequately study attributes endolymphatic hydrops, such as origins low-frequency hearing loss, a reliable model needed. The guinea pig good because it hears in regions are putatively affected by hydrops. Previous research has demonstrated can be induced surgically via intradural or extradural approaches involve drilling...

Stimulation of cholinergic efferent neurons innervating the inner ear has profound, well-characterized effects on vestibular and auditory physiology, after activating distinct ACh receptors (AChRs) afferents hair cells in peripheral endorgans. Efferent-mediated fast slow excitation are mediated by α4β2*-containing nicotinic AChRs (nAChRs) muscarinic (mAChRs), respectively. On side, efferent-mediated suppression distortion product otoacoustic emissions (DPOAEs) is α9α10nAChRs. Previous...