Pharmacological characterization and differential expression of NMDA receptor subunits in the chicken vestibular system during development.

Previous studies demonstrated that in vitro preparations of the isolated vestibular system of diverse animal species still exhibit stable resting electrical activity and mechanically evoked synaptic transmission between hair cells and primary afferent endings. However, there are no reports related to their neurodevelopment. Therefore, this research aimed to examine whether NMDA receptors mediate these electrical signals in an isolated preparation of the chicken vestibular system at three developmental stages, E15, E18, and E21. We found that the spontaneous and mechanically evoked discharges from primary afferents of the posterior semicircular canal were modulated by agonists NMDA and glycine, but not by the agonist d-serine applied near the synapses. Moreover, the individually applied by bath perfusion of three NMDA receptor antagonists (MK-801, ifenprodil, and 2-naphthoic acid) or high Mg2+ decreased the resting discharge rate, the NMDA response, and the discharge rate of mechanically evoked activity from these primary afferents. Furthermore, we found that the vestibular ganglion shows a stage-dependent increase in the expression of NMDA receptor subunits GluN1, GluN2 (A-C), and GluN3 (A-B), being greater at E21, except for GluN2D, which was inversely related to the developmental stage. However, in the crista ampullaris, the expression pattern remained constant throughout development. This could suggest the possible existence of presynaptic NMDA receptors. Our results highlight that although the NMDA receptors are functionally active at the early embryonic stages of the vestibular system, NMDA and glycine reach their mature functionality to increase NMDA responses close to hatching (E21).

The influence of vestibular system and fetal presentation on handedness, cognitive and motor development: A comparison between cephalic and breech presentation.

Genetics are undoubtedly implicated in the ontogenesis of laterality. Nonetheless, environmental factors, such as the intrauterine environment, may also play a role in the development of functional and behavioral lateralization. The aim of this study was to test the Left-Otolithic Dominance Theory (LODT; Previc, 1991) by investigating a hypothetical developmental pattern where it is assumed that a breech presentation, which is putatively associated with a dysfunctional and weakly lateralized vestibular system, can lead to weak handedness and atypical development associated with language and motor difficulties. We used the ALSPAC cohort of children from 7 to 10 years of age to conduct our investigation. Our results failed to show an association between the vestibular system and fetal presentation, nor any influence of the latter on hand preference, hand performance, or language and motor development. Bayesian statistical analyses supported these findings. Contrary to our LODT-derived hypotheses, this study offers evidence that fetal presentation does not influence the vestibular system's lateralization and seems to be a poor indicator for handedness. Nonetheless, we found that another non-genetic factor, prematurity, could lead to atypical development of handedness.

Ontogenetic variation in the crocodylian vestibular system.

Crocodylians today live in tropical to subtropical environments, occupying mostly shallow waters. Their body size changes drastically during ontogeny, as do their skull dimensions and bite forces, which are associated with changes in prey preferences. Endocranial neurosensory structures have also shown to change ontogenetically, but less is known about the vestibular system of the inner ear. Here we use 30 high-resolution computed tomography (CT) scans and three-dimensional geometric morphometrics to investigate the size and shape changes of crocodylian endosseous labyrinths throughout ontogeny, across four stages (hatchling, juvenile, subadult and adult). We find two major patterns of ontogenetic change. First, the labyrinth increases in size during ontogeny, with negative allometry in relation to skull size. Second, labyrinth shape changes significantly, with hatchlings having shorter semicircular canal radii, with thicker diameters and an overall dorsoventrally shorter labyrinth than those of more mature individuals. We argue that the modification of the labyrinth during crocodylian ontogeny is related to constraints imposed by skull growth, due to fundamental changes in the crocodylian braincase during ontogeny (e.g. verticalisation of the basicranium), rather than changes in locomotion, diet, or other biological functions or behaviours.

Purinergic signaling in the peripheral vestibular system.

The inner ear comprises the cochlea and vestibular system, which detect sound and acceleration stimulation, respectively. The function of the inner ear is regulated by ion transport activity among sensory epithelial cells, neuronal cells, non-sensory epithelial cells, and luminal fluid with a unique ionic composition of high [K+] and low [Na+], which enables normal hearing and balance maintenance. One of the important mechanisms regulating ion transport in the inner ear is purinergic signaling. Various purinergic receptors are distributed throughout inner ear epithelial cells and neuronal cells. To date, most studies have focused on the role of purinergic receptors in the cochlea, and few studies have examined these receptors in the vestibular system. As purinergic receptors play an important role in the cochlea, they would likely do the same in the vestibular system, which is fairly similar to the cochlea in cellular structure and function. Based on available studies performed to date, purinergic signaling is postulated to be involved in the regulation of ion homeostasis, protection of hair cells, otoconia formation, and regulation of electrical signaling from the sensory epithelium to vestibular neurons. In this review, the distribution and roles of purinergic receptors in the peripheral vestibular system are summarized and discussed.

A comprehensive review of the effects of caffeine on the auditory and vestibular systems.

Coffee, of which caffeine is a critical component, is probably the most frequently used psychoactive stimulant in the world. The effects of caffeine on the auditory and vestibular system have been investigated under normal and pathological conditions, such as acoustic trauma, ototoxicity, auditory neuropathy, and vestibular disorders, using various tests. Lower incidences of hearing loss and tinnitus have been reported in coffee consumers. The stimulatory effect of caffeine is represented by either a shorter latency or enhanced amplitude in electrophysiological tests of the auditory system. Furthermore, in the vestibular system, oculomotor testing revealed significant effects of caffeine, while other tests did not reveal any significant caffeine effects. It could be that caffeine improves transmission in the auditory and vestibular systems' central pathways. Importantly, the effects of caffeine seem to be dose-dependent. Also, inconsistent findings have been observed regarding caffeine's effects on the auditory and vestibular systems and related disorders. Overall, these findings suggest that caffeine does not strongly influence the peripheral auditory and vestibular systems. Instead, caffeine's effects seem to occur almost solely at the level of the central nervous system.

Health Care Resource Utilization and Costs for Adults With Mild Traumatic Brain Injury With Chronic Vestibular Impairment.

OBJECTIVE: To quantify the economic burden of all-cause health care resource utilization (HCRU) among adults with and without chronic vestibular impairment (CVI) after a mild traumatic brain injury (mTBI). DESIGN: Retrospective matched cohort study. SETTING: IQVIA Integrated Data Warehouse. PARTICIPANTS: People with mTBI+CVI (n=20,441) matched on baseline age, sex, year of mTBI event, and Charlson Comorbidity Index (CCI) score to people with mTBI only (n=20,441) (N=40,882). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: All-cause health HCRU and costs at 12 and 24 months post mTBI diagnosis. RESULTS: People with mTBI+CVI had significantly higher all-cause HCRU and costs at both time points than those with mTBI only. Multivariable regression analysis showed that, when controlling for baseline variables, costs of care were 1.5 times higher for mTBI+CVI than mTBI only. CONCLUSIONS: People who developed CVI after mTBI had greater overall HCRU and costs for up to 2 years after the injury event compared with people who did not develop CVI after controlling for age, sex, region, and CCI score. Further research on access to follow-up services and effectiveness of interventions to address CVI is warranted.

Kinematic Analysis of 360° Turning in Stroke Survivors Using Wearable Motion Sensors.

BACKGROUND: A stroke often bequeaths surviving patients with impaired neuromusculoskeletal systems subjecting them to increased risk of injury (e.g., due to falls) even during activities of daily living. The risk of injuries to such individuals can be related to alterations in their movement. Using inertial sensors to record the digital biomarkers during turning could reveal the relevant turning alterations. OBJECTIVES: In this study, movement alterations in stroke survivors (SS) were studied and compared to healthy individuals (HI) in the entire turning task due to its requirement of synergistic application of multiple bodily systems. METHODS: The motion of 28 participants (14 SS, 14 HI) during turning was captured using a set of four Inertial Measurement Units, placed on their sternum, sacrum, and both shanks. The motion signals were segmented using the temporal and spatial segmentation of the data from the leading and trailing shanks. Several kinematic parameters, including the range of motion and angular velocity of the four body segments, turning time, the number of cycles involved in the turning task, and portion of the stance phase while turning, were extracted for each participant. RESULTS: The results of temporal processing of the data and comparison between the SS and HI showed that SS had more cycles involved in turning, turn duration, stance phase, range of motion in flexion-extension, and lateral bending for sternum and sacrum (p-value < 0.035). However, HI exhibited larger angular velocity in flexion-extension for all four segments. The results of the spatial processing, in agreement with the prior method, showed no difference between the range of motion in flexion-extension of both shanks (p-value > 0.08). However, it revealed that the angular velocity of the shanks of leading and trailing legs in the direction of turn was more extensive in the HI (p-value < 0.01). CONCLUSIONS: The changes in upper/lower body segments of SS could be adequately identified and quantified by IMU sensors. The identified kinematic changes in SS, such as the lower flexion-extension angular velocity of the four body segments and larger lateral bending range of motion in sternum and sacrum compared to HI in turning, could be due to the lack of proper core stability and effect of turning on vestibular system of the participants. This research could facilitate the development of a targeted and efficient rehabilitation program focusing on the affected aspects of turning movement for the stroke community.

Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS): genetic and clinical aspects.

Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) typically presents in middle life with a combination of neuropathy, ataxia and vestibular disease, with patients reporting progressive imbalance, oscillopsia, sensory disturbance and a dry cough. Examination identifies a sensory neuropathy or neuronopathy and bilaterally impaired vestibulo-ocular reflex. The underlying genetic basis is of biallelic AAGGG expansions in the second intron of replication factor complex subunit 1 (RFC1). The frequency and phenotype spectrum of RFC1 disease is expanding, ranging from typical CANVAS to site-restricted variants affecting the sensory nerves, cerebellum and/or the vestibular system. Given the wide phenotype spectrum of RFC1, the differential diagnosis is broad. RFC1 disease due to biallelic AAGGG expansions is probably the most common cause of recessive ataxia. The key to suspecting the disease (and prompt genetic testing) is a thorough clinical examination assessing the three affected systems and noting the presence of chronic cough.

Transient Vestibular Symptoms Preceding Posterior Circulation Stroke: A Prospective Multicenter Study.

BACKGROUND AND PURPOSE: The recognition of clinical features of transient vestibular symptoms (TVSs) preceding posterior circulation stroke (PCOS) would be informative to discriminate dizziness/vertigo due to vertebrobasilar transient ischemic attack from the acute transient vestibular syndrome. We sought to determine the prevalence and characteristics of TVSs preceding PCOS. METHODS: We performed a prospective multicenter observational study that had recruited 447 patients with PCOS from referral-based 4 university hospitals in Korea. We investigated the timing, pattern, frequency, duration, and accompanying neurological symptoms of TVSs during the 3 months preceding PCOS. RESULTS: The prevalence of TVSs preceding PCOS was 12% (55/447) during the previous 3 months. The TVSs preceding PCOS occurred within 1 week (33%), between 1 week and 1 month (16%), or between 1 and 3 months (51%). The TVSs were mostly dizziness/vertigo with (36%) or without (60%) imbalance, while the remaining 4% had an isolated imbalance. The dizziness/vertigo was spinning in 38% and was aggravated during head position in 45%. The duration of TVSs was mostly a few seconds (55%) or minutes (38%). Approximately 72% of the patients with PCOS had TVSs 1 to 5 times, while 16% had >10 times. Accompanying neurological symptoms, including headache, tinnitus, limb weakness, sensory change, dysarthria, visual field defect, and diplopia, were reported in 11%. CONCLUSIONS: Preceding TVSs can occur in 12% of PCOS during the previous 3 months. Isolated dizziness/vertigo of unknown cause needs to be considered as a vertebrobasilar transient ischemic attack symptom, especially in patients with vascular risk factors. The characteristics of isolated vestibular symptom in vertebrobasilar transient ischemic attacks is highly variable and atypical compared with other transient ischemic symptoms.

Assessing head acceleration to identify a motor threshold to galvanic vestibular stimulation.

Galvanic vestibular stimulation (GVS) is used to assess vestibular system function, but vestibulospinal responses can exhibit variability depending on protocols or intensities used. Here, we measured head acceleration in healthy subjects to identify an objective motor threshold on which to base GVS intensity when assessing standing postural responses. Thirteen healthy right-handed subjects stood on a force platform, eyes closed, and head facing forward. An accelerometer was placed on the vertex to detect head acceleration, and electromyography activity of the right soleus was recorded. GVS (200 ms; current steps 0.5, from 1 mA to 4 mA) was applied in a binaural and bipolar configuration. 1) GVS induced a biphasic accelerometer response at a latency of 15 ms. Based on response amplitude, we constructed a recruitment curve for all participants and determined the motor threshold. In parallel, the method of limits was used to devise a more rapid approach to determine motor threshold. 2) We observed significant differences between motor threshold based on a recruitment curve and all perceptual thresholds reported either by the subject (sensation of movement) or a standing experimenter observing the participant (perception of movement). No significant difference was observed between the motor threshold based on the method of limits and perceptual thresholds of movement. 3) Using orthogonal polynomial contrasts, we observed a linear progression between multiples of the objective motor threshold (0.5, 0.75, 1, 1.5× motor threshold) and the 95% confidence ellipse area, the first peak of center of pressure displacement velocity, and the short and medium latency responses in the soleus. Hence, an objective motor threshold for GVS based on head acceleration was identified in standing participants and a recruitment curve could be constructed for all participants. These novel approaches could enable better understanding of changes in the vestibular system in different conditions or over time.NEW & NOTEWORTHY Galvanic vestibular stimulation (GVS) has been used to assess the vestibular system, but the significant interindividual variability in the responses makes it difficult to quantitatively compare them between individuals or conditions. Using an accelerometer to quantify head movement induced by GVS, we were able to determine an objective motor threshold and construct a recruitment curve for all participants. These methods could help assess changes in the vestibular system under different conditions.

What might cervical vestibular-evoked myogenic potential abnormalities mean in essential tremor?

AIM/BACKGROUND: Essential tremor (ET) is one of the most common movement disorders. However, its pathogenesis is unclear. Human vestibular reflexes are essential not only for gait and posture but also for goal-directed voluntary movements. In this study, cervical vestibular-evoked myogenic potentials (cVEMPs), the electrophysiological equivalent of the vestibulo-collic reflex was studied in ET patients to understand the interaction between the tremor network and the vestibular neural pathways. METHODS: cVEMPs were recorded in 40 ET patients and 40 age and sex-matched healthy controls (HCs). The latencies of peaks p13 and n23 and peak-to-peak amplitude of p13-n23 were measured. RESULTS: There was no statistically significant difference between the p13 latencies of the HC and ET groups (p 0.79 and p 0.23 for the right and left sides respectively). n23 latency was shortened bilaterally in the ET group (p 0.009 and p 0.02 for the right and left sides respectively). p13-n23 amplitudes of the ET patients were bilaterally reduced when compared with the HC (p <0.001 and p 0.001 for the right and left sides respectively). CONCLUSION: Information provided by vestibular afferents is crucial in the control of voluntary movements in humans. Despite this silent but significant effect, the role of the vestibular system in movement disorders is often overlooked. In this study, it was found that cVEMP responses reflecting the activity of the vestibulo-collic pathway were affected in ET which can be either caused by dysfunctional structures or pathways responsible from ET or an additional disorder of vestibular information processing in these patients.

Vestibular cues improve landmark-based route navigation: A simulated driving study.

It is well established that humans use self-motion and landmark cues to successfully navigate their environment. Existing research has demonstrated a critical role of the vestibular system in supporting navigation across many species. However, less is known about how vestibular cues interact with landmarks to promote successful navigation in humans. In the present study, we used a motion simulator to manipulate the presence or absence of vestibular cues during a virtual navigation task. Participants learned routes to a target destination in three different landmark blocks in a virtual town: one with proximal landmarks, one with distal landmarks, and one with no landmarks present. Afterwards, they were tested on their ability to retrace the route and find the target destination. We observed a significant interaction between vestibular cues and proximal landmarks, demonstrating that the potential for vestibular cues to improve route navigation is dependent on landmarks that are present in the environment. In particular, vestibular cues significantly improved route navigation when proximal landmarks were present, but this was not significant when distal landmarks or no landmarks were present. Overall, our results indicate that landmarks play an important role in the successful incorporation of vestibular cues to human spatial navigation.

The transcriptome characteristics of vestibular organs from delayed endolymphatic hydrops patients (Meniere's disease).

OBJECTIVES: To identify genes that are related to delayed endolymphatic hydrops (DEH) in patients by RNA-Seq analysis. DESIGN: Observational study. SETTING: Eye & ENT Hospital, Fudan University (Shanghai, China). PARTICIPANTS: We collected the entire vestibular system from four patients with DEH who underwent labyrinthectomy. Three control samples were collected from patients with acoustic neuroma or facial neuroma treated via the translabyrinthine approach. High-throughput RNA-Seq analysis was performed to investigate gene expression in the pathological vestibular system. MAIN OUTCOME MEASURES: Our bioinformatic analysis identified 17 genes that were upregulated and eight genes that were downregulated in patients with DEH compared with the controls. RESULTS: The altered gene expression profile suggested that DEH is closely related to neuropathy and autoimmune disease. In addition, many of the differentially regulated genes were involved in cell adhesion, suggesting a role of cell adhesion in DEH. Immunofluorescence analysis confirmed the expression of PMP2 and CLDN19 in the cytoplasm of hair cells and scattered expression of MPZ at cell junctions. The protein expression levels were higher in specimens from patients with Ménière's disease and DEH compared with controls. CONCLUSIONS: The protein expression profile of vestibular organs in patients with endolymphatic hydrops exhibited a degree of similarity to that of Ménière's disease. Endolymphatic hydrops is characterised by autoimmune abnormalities. DEH and Ménière's disease are likely to be different manifestations of the same disease, with disparate clinical symptoms. RNA-Seq is a useful analytical tool to characterise the vestibular pathology based on its transcriptome.

Herpes zoster oticus. / Herpes zoster oticus.

BACKGROUND: Herpes zoster oticus is a rare neurological disease caused by reactivation of varicella-zoster virus in the facial nerve. CASE PRESENTATION: A woman in her 60 s presented with left-sided seventh and eighth cranial neuropathy. A vesicular rash in her left ear and palate appeared one week after symptom onset. Lumbar puncture revealed cerebrospinal fluid (CSF) pleocytosis, mononuclear cells only, with PCR positive for varicella zoster virus. Inflammation of the cochlear and vestibular systems and along the facial nerve was detected by MRI. Antiviral treatment with valacyclovir in combination with prednisolone was initiated. After one month with outpatient rehabilitation, the vertigo had ceased, but hearing loss and facial paralysis persisted. INTERPRETATION: Early diagnosis and treatment of herpes zoster oticus as a cause of facial palsy when accompanied by ear rash, pain or signs of other cranial nerve involvement may improve overall prognosis.

[Effects of cochlear implantation on vestibular function]. / Vozdeistvie kokhlearnoi implantatsii na vestibulyarnuyu funktsiyu.

The literature review is devoted to the effects arising from the effect of a cochlear implant on the vestibular system. Due to the pronounced anatomical proximity and physiological interaction of vestibular receptors with the cochlea, the installation of a cochlear implant and its electrical activity are associated with an effect on the vestibular system. The analysis of the works of foreign and domestic researchers who carried out monitoring of vestibular function in patients after cochlear implantation using modern objective methods was carried out.

Long term effects of cochlear implant surgery on vestibular system in pediatric population.

OBJECTIVE: The aim was to evaluate the vestibular system of children who had undergone cochlear implant surgery and to compare them with the healthy population by vestibulo-ocular reflex (VOR) gains in unilateral and bilateral implant users, with the implants both on and off. METHODS: Patients older than 5 years who had undergone cochlear implant surgery between 2012 and 2020 and who were cochlear implant users for at least one year were included. After consent was obtained, a video head impulse test (VHIT) was performed to evaluate the three semicircular canals, with devices on and off, and VOR gains were evaluated. VHIT was also used to assess VOR gains in the control group. The VOR gains of the study and control groups, VOR gains of unilateral and bilateral implant users, and VOR gains with implants on and off were compared. RESULTS: When the VOR gains of 24 unilateral and 13 bilateral cochlear implant users and the control group (n = 30) were compared, a significant difference was found only in the anterior semicircular canal, although the VOR gains were found to be low in all three semicircular canals in the implant users (p < 0.05). There was no significant difference between the VOR gains of unilateral and bilateral implant users. There was no significant difference between the VOR gains when either on or off. There was no correlation between cochlear implant usage time, implant insertion age, patient age and VOR gain. CONCLUSION: The effects of cochlear implant surgery on the vestibular system continue in the late period, but no correlation was observed between implant usage time and VOR gain after the first year. It was observed that having the cochlear implant on or off had no effect on VOR gain. Furthermore, bilateral implant surgery did not lead to additional vestibular dysfunction compared to unilateral implant surgery.

Mitophagy Decreases in the Peripheral Vestibular System of Aged C57BL/6J Mice.

BACKGROUND/AIM: Mitophagy is a cardinal process for maintaining healthy and functional mitochondria. A decline in mitophagy has been associated with age-related pathologies. We aimed to investigate mitophagy changes in age-related balance problems using an animal model. MATERIALS AND METHODS: C57BL/6J mice were divided into young (1 month old) and aged (12 months old) groups. Balance performance, mitochondrial DNA integrity, ATP content, mitophagic process, and mitophagy-related genes and proteins were investigated in both groups. RESULTS: Balance and motor performance were reduced in the aged group. Mitochondrial DNA integrity and ATP content, and mRNA levels of PINK1, Parkin, BNIP3, AMBRA1, MUL1, NIX, Bcl2-L-13, Atg3, Atg5, Atg12, and Atg13 in the vestibule were significantly lower in aged mice compared with those in young mice. The protein levels of PINK1, Parkin, BNIP3, LC3B, and OXPHOS subunits were significantly decreased in the aged vestibule. Mitophagosome and mitophagolysosome counts and the immunohistochemical expression of Parkin and BNIP3 were also decreased in the saccule, utricle, and crista ampullaris in the aged group. CONCLUSION: A general decrease in mitophagy with aging might be attributed to a decrease in cellular function in the aged vestibule during the development of age-related balance problems.

Frequency-Dependent Reduction of Cybersickness in Virtual Reality by Transcranial Oscillatory Stimulation of the Vestibular Cortex.

Virtual reality (VR) applications are pervasive of everyday life, as in working, medical, and entertainment scenarios. There is yet no solution to cybersickness (CS), a disabling vestibular syndrome with nausea, dizziness, and general discomfort that most of VR users undergo, which results from an integration mismatch among visual, proprioceptive, and vestibular information. In a double-blind, controlled trial, we propose an innovative treatment for CS, consisting of online oscillatory imperceptible neuromodulation with transcranial alternating current stimulation (tACS) at 10 Hz, biophysically modelled to reach the vestibular cortex bilaterally. tACS significantly reduced CS nausea in 37 healthy subjects during a VR rollercoaster experience. The effect was frequency-dependent and placebo-insensitive. Subjective benefits were paralleled by galvanic skin response modulation in 25 subjects, addressing neurovegetative activity. Besides confirming the role of transcranially delivered oscillations in physiologically tuning the vestibular system function (and dysfunction), results open a new way to facilitate the use of VR in different scenarios and possibly to help treating also other vestibular dysfunctions.

In vivo investigation of mitochondria in lateral line afferent neurons and hair cells.

To process sensory stimuli, intense energy demands are placed on hair cells and primary afferents. Hair cells must both mechanotransduce and maintain pools of synaptic vesicles for neurotransmission. Furthermore, both hair cells and afferent neurons must continually maintain a polarized membrane to propagate sensory information. These processes are energy demanding and therefore both cell types are critically reliant on mitochondrial health and function for their activity and maintenance. Based on these demands, it is not surprising that deficits in mitochondrial health can negatively impact the auditory and vestibular systems. In this review, we reflect on how mitochondrial function and dysfunction are implicated in hair cell-mediated sensory system biology. Specifically, we focus on live imaging approaches that have been applied to study mitochondria using the zebrafish lateral-line system. We highlight the fluorescent dyes and genetically encoded biosensors that have been used to study mitochondria in lateral-line hair cells and afferent neurons. We then describe the impact this in vivo work has had on the field of mitochondrial biology as well as the relationship between mitochondria and sensory system development, function, and survival. Finally, we delineate the areas in need of further exploration. This includes in vivo analyses of mitochondrial dynamics and biogenesis, which will round out our understanding of mitochondrial biology in this sensitive sensory system.

Vestibular modulation of the tail of the rat striatum.

Fragmented and piecemeal evidence from animal and human studies suggests that vestibular information is transmitted to the striatum, a part of the basal ganglia that degenerates in Parkinson's Disease. Nonetheless, surprisingly little is known about the precise effects of activation of the vestibular system on the striatum. Electrophysiological studies have yielded inconsistent results, with many studies reporting only sparse responses to vestibular stimulation in the dorsomedial striatum. In this study, we sought to elucidate the effects of electrical stimulation of the peripheral vestibular system on electrophysiological responses in the tail of the rat striatum, a newly discovered region for sensory input. Rats were anaesthetised with urethane and a bipolar stimulating electrode was placed in the round window in order to activate the peripheral vestibular system. A recording electrode was positioned in the tail of the striatum. Local field potentials (LFPs) were recorded ipsilaterally and contralaterally to the stimulation using a range of current parameters. In order to confirm that the vestibular system was activated, video-oculography was used to monitor vestibular nystagmus. At current amplitudes that evoked vestibular nystagmus, clear triphasic LFPs were evoked in the bilateral tail of the striatum, with the first phase of the waveform exhibiting latencies of less than 22 ms. The LFP amplitude increased with increasing current amplitude (P ≤ 0.0001). In order to exclude the possibility that the LFPs were evoked by the activation of the auditory system, the cochlea was surgically lesioned in some animals. In these animals the LFPs persisted despite the cochlear lesions, which were verified histologically. Overall, the results obtained suggest that there are vestibular projections to the tail of the striatum, which could possibly arise from projections via the vestibular nucleus or cerebellum and the parafasicular nucleus of the thalamus.