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Takeda N, Matsuda K, Fukuda J, Sato G, Uno A, Kitahara T. Vestibular compensation: Neural mechanisms and clinical implications for the treatment of vertigo. Auris Nasus Larynx 2024; 51:328-336. [PMID: 38114342 DOI: 10.1016/j.anl.2023.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/21/2023]
Abstract
After unilateral peripheral vestibular lesions, the neural activity of neurons in the ipsi-lesional medial vestibular nucleus (ipsi-MVe) are markedly decreased, resulting in static and dynamic asymmetries of the vestibulo-ocular and vestibulo-spinal reflexes. Consequently, static vestibular symptoms such as spontaneous nystagmus and postural deviation and dynamic vestibular symptoms such as oscillopsia and swaying gait are induced. However, these behavioral asymmetries gradually recover after the lesion. Progressive balance restoration is termed vestibular compensation, which is divided into two phases: static and dynamic. Static vestibular compensation is further divided into initial and late processes. In the initial process of static vestibular compensation after unilateral labyrinthectomy (UL) in rats, plastic changes in the cerebello-vestibular and vestibular commissural inhibitory pathways suppress neurons in the contra-lesional MVe (contra-MVe), resulting in the restoration of symmetrical resting activity of MVe neurons on both sides at low levels. The declining frequency of spontaneous nystagmus after UL is an index of the initial process, and short-term administration of diazepam, a GABAA receptor agonist, has been shown to accelerate the initial process in rats. Accordingly, short-term administration of diazepam is recommended for the treatment of acute vertigo in patients with unilateral vestibular dysfunction. In the late process of static vestibular compensation after UL in rats, the resting activity of ipsi-MVe neurons gradually recovers due to changes in cell membrane properties, resulting in the reinforcement of balanced intervestibular nuclear activities to nearly normal levels without the suppression of contra-MVe neurons. The declining number of MK801-induced Fos-positive neurons in contra-MVe after UL is an index of the late process, and long-term administration of betahistine, a histamine H3 receptor antagonist, has been shown to accelerate the late process in rats. Accordingly, long-term administration of betahistine is recommended for the treatment of subacute vertigo in patients who were not compensated for unilateral vestibular dysfunction. In the process of dynamic vestibular compensation after UL, the sensitivity of ipsi-MVe neurons to head velocity and acceleration is restored due to synaptic changes such as long-term potentiation and sprouting of commissures, resulting in the restoration of the dynamic vestibulo-ocular and vestibulo-spinal reflexes. To facilitate dynamic vestibular compensation, early ambulation and subsequent vestibular rehabilitation exercise are recommended for the treatment of chronic vertigo in patients with uncompensated unilateral vestibular dysfunction. Although vestibular compensation after bilateral vestibular loss is not expected, vestibular rehabilitation with a sensory-substitution strategy can improve imbalance in patients with bilateral vestibular lesions.
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Affiliation(s)
- Noriaki Takeda
- Department of Otolaryngology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan.
| | - Kazunori Matsuda
- Department of Otolaryngology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Junya Fukuda
- Department of Otolaryngology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Go Sato
- Department of Otolaryngology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Atsuhiko Uno
- Department of Otolaryngology-Head and Neck Surgery, Osaka General Medical Center, Osaka, Japan
| | - Tadashi Kitahara
- Department of Otolaryngology Head and Neck Surgery, Nara Medical University, Kashihara, Japan
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Weston AR, Doar G, Dibble LE, Loyd BJ. Vestibular Decompensation Following COVID-19 Infection in a Person With Compensated Unilateral Vestibular Loss: A Rehabilitation Case Study. J Neurol Phys Ther 2024; 48:112-118. [PMID: 38414133 DOI: 10.1097/npt.0000000000000465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
BACKGROUND AND PURPOSE Surgical removal of a vestibular schwannoma (vestibular schwannoma resection; VSR) results in a unilateral vestibular hypofunction with complaints of dizziness and imbalance. Although the anatomic lesion is permanent, recovery of balance and diminution of dizziness occurs through central neurophysiologic compensation. Compensation of the system is maintained through daily activity. Unfortunately, interruption of stimulus, such as decreased activities due to illness, can cause decompensation. Decompensation is described as the return of symptoms consistent with that experienced during the initial insult/injury (eg, dizziness, oscillopsia, balance difficulty). This case study describes a reoccurrence of vestibular dysfunction in a person with a history of VSR following hospitalization and protracted recovery from a COVID-19 infection. It further documents her recovery that may be a result of vestibular rehabilitation. CASE DESCRIPTION A 49-year-old woman (M.W.) with a surgical history of VSR (10 years prior) and a medical history of significant COVID-19 infection, resulting in an intensive care unit stay and prolonged use of supplemental oxygen, presented to physical therapy with persistent dizziness and imbalance. The video head impulse test confirmed unilateral vestibular hypofunction. INTERVENTION M.W. attended biweekly vestibular rehabilitation for 6 weeks and completed daily home exercises. OUTCOMES At discharge, M.W. demonstrated improvements in patient-reported outcomes (Dizziness Handicap Inventory), functional testing (MiniBEST, 2-Minute Walk Test), and gaze stability measures (video head impulse testing, dynamic visual acuity). DISCUSSION Vestibular decompensation preluded by a COVID-19 infection caused a significant decrease in functional mobility. Vestibular rehabilitation targeted at gaze and postural stability effectively reduced symptoms and facilitated recovery to M.W.'s pre-COVID-19 level of function. Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A458 ).
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Affiliation(s)
- Angela R Weston
- Department of Physical Therapy and Athletic Training (A.R.W., G.D., L.E.D.), The University of Utah, Salt Lake City; Army Baylor University Doctoral Program in Physical Therapy (A.R.W.), U.S. Army Medical Center of Excellence, San Antonio; and School of Physical Therapy and Rehabilitation Sciences & School of Integrative Physiology and Athletic Training (B.J.L.), University of Montana, Missoula
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Aryan R, Zobeiri OA, Millar JL, Schubert MC, Cullen KE. Effect of vestibular loss on head-on-trunk stability in individuals with vestibular schwannoma. Sci Rep 2024; 14:3512. [PMID: 38347021 PMCID: PMC10861475 DOI: 10.1038/s41598-024-53512-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/01/2024] [Indexed: 02/15/2024] Open
Abstract
The vestibulo-collic reflex generates neck motor commands to produce head-on-trunk movements that are essential for stabilizing the head relative to space. Here we examined the effects of vestibular loss on head-on-trunk kinematics during voluntary behavior. Head and trunk movements were measured in individuals with vestibular schwannoma before and then 6 weeks after unilateral vestibular deafferentation via surgical resection of the tumor. Movements were recorded in 6 dimensions (i.e., 3 axes of rotation and 3 axes of translation) using small light-weight inertial measurement units while participants performed balance and gait tasks. Kinematic measures differed between individuals with vestibular schwannoma (at both time points) and healthy controls for the more challenging exercises, namely those performed in tandem position or on an unstable surface without visual input. Quantitative assessment of the vestibulo-ocular reflex (VOR) revealed a reduction in VOR gain for individuals with vestibular schwannoma compared to control subjects, that was further reduced following surgery. These findings indicated that the impairment caused by either the tumor or subsequent surgical tumor resection altered head-on-trunk kinematics in a manner that is not normalized by central compensation. In contrast, we further found that head-on-trunk kinematics in individuals with vestibular schwannoma were actually comparable before and after surgery. Thus, taken together, our results indicate that vestibular loss impacts head-on-trunk kinematics during voluntary balance and gait behaviors, and suggest that the neural mechanisms mediating adaptation alter the motion strategies even before surgery in a manner that may be maladaptive for long-term compensation.
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Affiliation(s)
- Raabeae Aryan
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 504, Baltimore, MD, 21205-2109, USA
| | - Omid A Zobeiri
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 504, Baltimore, MD, 21205-2109, USA
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Jennifer L Millar
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael C Schubert
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 504, Baltimore, MD, 21205-2109, USA.
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada.
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, USA.
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA.
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA.
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Rastoldo G, Tighilet B. The Vestibular Nuclei: A Cerebral Reservoir of Stem Cells Involved in Balance Function in Normal and Pathological Conditions. Int J Mol Sci 2024; 25:1422. [PMID: 38338702 PMCID: PMC10855768 DOI: 10.3390/ijms25031422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/18/2024] [Accepted: 01/20/2024] [Indexed: 02/12/2024] Open
Abstract
In this review, we explore the intriguing realm of neurogenesis in the vestibular nuclei-a critical brainstem region governing balance and spatial orientation. We retrace almost 20 years of research into vestibular neurogenesis, from its discovery in the feline model in 2007 to the recent discovery of a vestibular neural stem cell niche. We explore the reasons why neurogenesis is important in the vestibular nuclei and the triggers for activating the vestibular neurogenic niche. We develop the symbiotic relationship between neurogenesis and gliogenesis to promote vestibular compensation. Finally, we examine the potential impact of reactive neurogenesis on vestibular compensation, highlighting its role in restoring balance through various mechanisms.
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Affiliation(s)
- Guillaume Rastoldo
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, 13331 Marseille, France;
| | - Brahim Tighilet
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, 13331 Marseille, France;
- GDR Vertige CNRS Unité GDR2074, 13331 Marseille, France
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Millar JL, Zobeiri OA, Souza WH, Schubert MC, Cullen KE. Head movement kinematics are differentially altered for extended versus short duration gait exercises in individuals with vestibular loss. Sci Rep 2023; 13:16213. [PMID: 37758749 PMCID: PMC10533850 DOI: 10.1038/s41598-023-42441-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/10/2023] [Indexed: 09/29/2023] Open
Abstract
Head kinematics are altered in individuals with vestibular schwannoma (VS) during short duration gait tasks [i.e., Functional Gait Assessment (FGA)], both before and after surgery, yet whether these differences extend to longer duration gait exercises is currently unknown. Here we examined the effects of vestibular loss and subsequent compensation on head kinematics in individuals with VS during gait exercises of relatively extended versus short duration (< 10 versus 30 s), compared to age-matched controls. Six-dimensional head movements were recorded during extended and short duration gait exercises before and then 6 weeks after sectioning of the involved vestibular nerve (vestibular neurectomy). Standard functional, physiological, and subjective clinical assessments were also performed at each time point. Kinematics were differentially altered in individuals with vestibular loss at both time points during extended versus short duration exercises. Range of motion was significantly reduced in extended tasks. In contrast, movement variability predominately differed for the short duration exercises. Overall, our results indicate that quantifying head kinematics during longer duration gait tasks can provide novel information about how VS individuals compensate for vestibular loss, and suggest that measurements of range of motion versus variability can provide information regarding the different strategies deployed to maintain functional locomotion.
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Affiliation(s)
- Jennifer L Millar
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Omid A Zobeiri
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Wagner H Souza
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 504, Baltimore, MD, 21205-2109, USA
| | - Michael C Schubert
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 504, Baltimore, MD, 21205-2109, USA
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 504, Baltimore, MD, 21205-2109, USA.
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA.
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA.
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El Mahmoudi N, Laurent C, Péricat D, Watabe I, Lapotre A, Jacob PY, Tonetto A, Tighilet B, Sargolini F. Long-lasting spatial memory deficits and impaired hippocampal plasticity following unilateral vestibular loss. Prog Neurobiol 2023; 223:102403. [PMID: 36821981 DOI: 10.1016/j.pneurobio.2023.102403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/25/2022] [Accepted: 01/04/2023] [Indexed: 02/23/2023]
Abstract
Unilateral vestibular loss (UVL) induces a characteristic vestibular syndrome composed of various posturo-locomotor, oculomotor, vegetative and perceptivo-cognitive symptoms. Functional deficits are progressively recovered over time during vestibular compensation, that is supported by the expression of multiscale plasticity mechanisms. While the dynamic of post-UVL posturo-locomotor and oculomotor deficits is well characterized, the expression over time of the cognitive deficits, and in particular spatial memory deficits, is still debated. In this study we aimed at investigating spatial memory deficits and their recovery in a rat model of unilateral vestibular neurectomy (UVN), using a wide spectrum of behavioral tasks. In parallel, we analyzed markers of hippocampal plasticity involved in learning and memory. Our results indicate the UVN affects all domains of spatial memory, from working memory to reference memory and object-in-place recognition. These deficits are associated with long-lasting impaired plasticity in the ipsilesional hippocampus. These results highlight the crucial role of symmetrical vestibular information in spatial memory and contribute to a better understanding of the cognitive disorders observed in vestibular patients.
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Affiliation(s)
- Nada El Mahmoudi
- Aix-Marseille Université -CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France.
| | - Célia Laurent
- Aix-Marseille Université -CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - David Péricat
- Université de Toulouse Paul Sabatier -CNRS, Institut de pharmacologie et de biologie structurale, Toulouse, France
| | - Isabelle Watabe
- Aix-Marseille Université -CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Agnès Lapotre
- Aix-Marseille Université -CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Pierre-Yves Jacob
- Aix-Marseille Université -CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Alain Tonetto
- Aix Marseille Université-CNRS, Centrale Marseille, FSCM (FR 1739), PRATIM, F-13397 Marseille, France
| | - Brahim Tighilet
- Aix-Marseille Université -CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Francesca Sargolini
- Aix-Marseille Université -CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France.
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Mildren RL, Cullen KE. Vestibular Contributions to Primate Neck Postural Muscle Activity during Natural Motion. J Neurosci 2023; 43:2326-2337. [PMID: 36801822 PMCID: PMC10072293 DOI: 10.1523/jneurosci.1831-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/10/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023] Open
Abstract
To maintain stable posture of the head and body during our everyday activities, the brain integrates information across multiple sensory systems. Here, we examined how the primate vestibular system, independently and in combination with visual sensory input, contributes to the sensorimotor control of head posture across the range of dynamic motion experienced during daily life. We recorded activity of single motor units in the splenius capitis and sternocleidomastoid muscles in rhesus monkeys during yaw rotations spanning the physiological range of self-motion (up to 20 Hz) in darkness. Splenius capitis motor unit responses continued to increase with frequency up to 16 Hz in normal animals, and were strikingly absent following bilateral peripheral vestibular loss. To determine whether visual information modulated these vestibular-driven neck muscle responses, we experimentally controlled the correspondence between visual and vestibular cues of self-motion. Surprisingly, visual information did not influence motor unit responses in normal animals, nor did it substitute for absent vestibular feedback following bilateral peripheral vestibular loss. A comparison of muscle activity evoked by broadband versus sinusoidal head motion further revealed that low-frequency responses were attenuated when low- and high-frequency self-motion were experienced concurrently. Finally, we found that vestibular-evoked responses were enhanced by increased autonomic arousal, quantified via pupil size. Together, our findings directly establish the vestibular system's contribution to the sensorimotor control of head posture across the dynamic motion range experienced during everyday activities, as well as how vestibular, visual, and autonomic inputs are integrated for postural control.SIGNIFICANCE STATEMENT Our sensory systems enable us to maintain control of our posture and balance as we move through the world. Notably, the vestibular system senses motion of the head and sends motor commands, via vestibulospinal pathways, to axial and limb muscles to stabilize posture. By recording the activity of single motor units, here we show, for the first time, that the vestibular system contributes to the sensorimotor control of head posture across the dynamic motion range experienced during everyday activities. Our results further establish how vestibular, autonomic, and visual inputs are integrated for postural control. This information is essential for understanding both the mechanisms underlying the control of posture and balance, and the impact of the loss of sensory function.
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Affiliation(s)
- Robyn L Mildren
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
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Cullen KE. Vestibular motor control. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:31-54. [PMID: 37562876 DOI: 10.1016/b978-0-323-98818-6.00022-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The vestibular system is an essential sensory system that generates motor reflexes that are crucial for our daily activities, including stabilizing the visual axis of gaze and maintaining head and body posture. In addition, the vestibular system provides us with our sense of movement and orientation relative to space and serves a vital role in ensuring accurate voluntary behaviors. Neurophysiological studies have provided fundamental insights into the functional circuitry of vestibular motor pathways. A unique feature of the vestibular system compared to other sensory systems is that the same central neurons that receive direct input from the afferents of the vestibular component of the 8th nerve can also directly project to motor centers that control vital vestibular motor reflexes. In turn, these reflexes ensure stabilize gaze and the maintenance of posture during everyday activities. For instance, a direct three-neuron pathway mediates the vestibulo-ocular reflex (VOR) pathway to provide stable gaze. Furthermore, recent studies have advanced our understanding of the computations performed by the cerebellum and cortex required for motor learning, compensation, and voluntary movement and navigation. Together, these findings have provided new insights into how the brain ensures accurate self-movement during our everyday activities and have also advanced our knowledge of the neurobiological mechanisms underlying disorders of vestibular processing.
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Affiliation(s)
- Kathleen E Cullen
- Departments of Biomedical Engineering, of Otolaryngology-Head and Neck Surgery, and of Neuroscience; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States.
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A prosthesis utilizing natural vestibular encoding strategies improves sensorimotor performance in monkeys. PLoS Biol 2022; 20:e3001798. [PMID: 36103550 PMCID: PMC9473632 DOI: 10.1371/journal.pbio.3001798] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022] Open
Abstract
Sensory pathways provide complex and multifaceted information to the brain. Recent advances have created new opportunities for applying our understanding of the brain to sensory prothesis development. Yet complex sensor physiology, limited numbers of electrodes, and nonspecific stimulation have proven to be a challenge for many sensory systems. In contrast, the vestibular system is uniquely suited for prosthesis development. Its peripheral anatomy allows site-specific stimulation of 3 separate sensory organs that encode distinct directions of head motion. Accordingly, here, we investigated whether implementing natural encoding strategies improves vestibular prosthesis performance. The eye movements produced by the vestibulo-ocular reflex (VOR), which plays an essential role in maintaining visual stability, were measured to quantify performance. Overall, implementing the natural tuning dynamics of vestibular afferents produced more temporally accurate VOR eye movements. Exploration of the parameter space further revealed that more dynamic tunings were not beneficial due to saturation and unnatural phase advances. Trends were comparable for stimulation encoding virtual versus physical head rotations, with gains enhanced in the latter case. Finally, using computational methods, we found that the same simple model explained the eye movements evoked by sinusoidal and transient stimulation and that a stimulation efficacy substantially less than 100% could account for our results. Taken together, our results establish that prosthesis encodings that incorporate naturalistic afferent dynamics and account for activation efficacy are well suited for restoration of gaze stability. More generally, these results emphasize the benefits of leveraging the brain’s endogenous coding strategies in prosthesis development to improve functional outcomes.
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How Peripheral Vestibular Damage Affects Velocity Storage: a Causative Explanation. JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY : JARO 2022; 23:551-566. [PMID: 35768706 PMCID: PMC9437187 DOI: 10.1007/s10162-022-00853-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/30/2022] [Indexed: 10/17/2022]
Abstract
Velocity storage is a centrally-mediated mechanism that processes peripheral vestibular inputs. One prominent aspect of velocity storage is its effect on dynamic responses to yaw rotation. Specifically, when normal human subjects are accelerated to constant angular yaw velocity, horizontal eye movements and perceived angular velocity decay exponentially with a time constant circa 15-30 s, even though the input from the vestibular periphery decays much faster (~ 6 s). Peripheral vestibular damage causes a time constant reduction, which is useful for clinical diagnoses, but a mechanistic explanation for the relationship between vestibular damage and changes in these behavioral dynamics is lacking. It has been hypothesized that Bayesian optimization determines ideal velocity storage dynamics based on statistics of vestibular noise and experienced motion. Specifically, while a longer time constant would make the central estimate of angular head velocity closer to actual head motion, it may also result in the accumulation of neural noise which simultaneously degrades precision. Thus, the brain may balance these two effects by determining the time constant that optimizes behavior. We applied a Bayesian optimal Kalman filter to determine the ideal velocity storage time constant for unilateral damage. Predicted time constants were substantially lower than normal and similar to patients. Building on our past work showing that Bayesian optimization explains age-related changes in velocity storage, we also modeled interactions between age-related hair cell loss and peripheral damage. These results provide a plausible mechanistic explanation for changes in velocity storage after peripheral damage. Results also suggested that even after peripheral damage, noise originating in the periphery or early central processing may remain relevant in neurocomputations. Overall, our findings support the hypothesis that the brain optimizes velocity storage based on the vestibular signal-to-noise ratio.
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Le Ray D, Guayasamin M. How Does the Central Nervous System for Posture and Locomotion Cope With Damage-Induced Neural Asymmetry? Front Syst Neurosci 2022; 16:828532. [PMID: 35308565 PMCID: PMC8927091 DOI: 10.3389/fnsys.2022.828532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/07/2022] [Indexed: 12/28/2022] Open
Abstract
In most vertebrates, posture and locomotion are achieved by a biomechanical apparatus whose effectors are symmetrically positioned around the main body axis. Logically, motor commands to these effectors are intrinsically adapted to such anatomical symmetry, and the underlying sensory-motor neural networks are correspondingly arranged during central nervous system (CNS) development. However, many developmental and/or life accidents may alter such neural organization and acutely generate asymmetries in motor operation that are often at least partially compensated for over time. First, we briefly present the basic sensory-motor organization of posturo-locomotor networks in vertebrates. Next, we review some aspects of neural plasticity that is implemented in response to unilateral central injury or asymmetrical sensory deprivation in order to substantially restore symmetry in the control of posturo-locomotor functions. Data are finally discussed in the context of CNS structure-function relationship.
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Seemungal BM, Agrawal Y, Bisdorff A, Bronstein A, Cullen KE, Goadsby PJ, Lempert T, Kothari S, Lim PB, Magnusson M, Marcus HJ, Strupp M, Whitney SL. The Bárány Society position on 'Cervical Dizziness'. J Vestib Res 2022; 32:487-499. [PMID: 36404562 PMCID: PMC9837683 DOI: 10.3233/ves-220202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper describes the Bárány Society Classification OverSight Committee (COSC) position on Cervical Dizziness, sometimes referred to as Cervical Vertigo. This involved an initial review by a group of experts across a broad range of fields, and then subsequent review by the Bárány Society COSC. Based upon the so far published literature, the Bárány Society COSC takes the view that the evidence supporting a mechanistic link between an illusory sensation of self-motion (i.e. vertigo - spinning or otherwise) and neck pathology and/or symptoms of neck pain - either by affecting the cervical vertebrae, soft tissue structures or cervical nerve roots - is lacking. When a combined head and neck movement triggers an illusory sensation of spinning, there is either an underlying common vestibular condition such as migraine or BPPV or less commonly a central vestibular condition including, when acute in onset, dangerous conditions (e.g. a dissection of the vertebral artery with posterior circulation stroke and, exceedingly rarely, a vertebral artery compression syndrome). The Committee notes, that migraine, including vestibular migraine, is by far, the commonest cause for the combination of neck pain and vestibular symptoms. The committee also notes that since head movement aggravates symptoms in almost any vestibular condition, the common finding of increased neck muscle tension in vestibular patients, may be linked as both cause and effect, to reduced head movements. Additionally, there are theoretical mechanisms, which have not been explored, whereby cervical pain may promote vaso-vagal, cardio-inhibitory reflexes and hence by presyncopal mechanisms, elicit transient disorientation and/or imbalance. The committee accepts that further research is required to answer the question as to whether those rare cases in which neck muscle spasm is associated with a vague sense of spatial disorientation and/or imbalance, is indeed linked to impaired neck proprioception. Future studies should ideally be placebo controlled and double-blinded where possible, with strict inclusion and exclusion criteria that aim for high specificity at the cost of sensitivity. To facilitate further studies in "cervical dizziness/vertigo", we provide a narrative view of the important confounds investigators should consider when designing controlled mechanistic and therapeutic studies. Hence, currently, the Bárány COSC refrains from proposing any preliminary diagnostic criteria for clinical use outside a research study. This position may change as new research evidence is provided.
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Affiliation(s)
- Barry M. Seemungal
- Centre for Vestibular Neurology, Department of Brain Sciences, Imperial College London, UK
| | - Yuri Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Alexander Bisdorff
- Department of Neurology, Centre Hospitalier Emile Mayrisch, Esch-sur-Alzette, Luxembourg
| | - Adolfo Bronstein
- Centre for Vestibular Neurology, Department of Brain Sciences, Imperial College London, UK
| | - Kathleen E. Cullen
- Departments of Biomedical Engineering, Neuroscience, and Otolaryngology - Head and Neck Surgery, Johns Hopkins University, Baltimore, USA
| | - Peter J. Goadsby
- King’s College London, UK & University of California, Los Angeles, USA
| | - Thomas Lempert
- Department of Neurology, Schlosspark-Klinik, Berlin, Germany
| | - Sudhir Kothari
- Department of Neurology, Poona Hospital and Research Centre, Pune, India
| | - Phang Boon Lim
- Cardiology Department, Hammersmith Hospital, Imperial College London, UK
| | - Måns Magnusson
- Department of Otorhinolaryngology and Clinical Sciences, Lund University & Skane University Hospital, Sweden
| | - Hani J. Marcus
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, Germany
| | - Susan L. Whitney
- School of Health and Rehabilitation Sciences, Department of Physical Therapy, University of Pittsburgh, USA
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13
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Anastasopoulos D, Anastasopoulos L, Mergner T. Voluntary suppression of neck reflexes during passive head-on-trunk rotations - reflex gain control vs. proprioceptive feedback. J Neurophysiol 2021; 127:161-172. [PMID: 34907798 PMCID: PMC8858664 DOI: 10.1152/jn.00297.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Normal subjects can completely eliminate resistance upon imposed head-on-trunk rotations when they are asked to relax. It is not, however, clear how neck reflexes to stretch can be voluntarily suppressed. Reflexive responses might be modified by adjusting the gain of the reflex loop through descending control. Theoretically, necessary corrections upon interfering disturbances during coordinated motor performance requiring the interplay of relaxation/activation may be missing if muscle relaxation is taking place exclusively by this mechanism. It has been alternatively proposed that sensory information from the periphery may be allowed to “neutralize” neck reflexes if it is fed back with opposite sign to the structures driving the reflexes. Six healthy subjects were asked to relax while subjected to head-on-trunk rotations generated by a head motor. After any initial resistance had completely subsided, the head was unexpectedly exposed to “ramp-and-hold” perturbations of up to 2° amplitude and 0.7 s duration. Resistance to stretch consistently reappeared thereupon, suggesting that stretch reflex gain had not been set to zero during the previously achieved complete relaxation. Resistance to perturbations under these circumstances was compared with the forces generated when the same ramp-and-hold displacements were delivered unpredictably to the head held stationary. A quantitative model of neck proprioceptive reflexes suppression has been thus constructed. Gain scheduling or “motor set” cannot sufficiently account for the voluntary reflex suppression during slow passive head rotations. Instead, we propose as underlying mechanism, the “neutralization” of the controlling servo by means of continuous feedback tracking displacement and force signals from the periphery. NEW & NOTEWORTHY Head stabilizing neck reflexes can be voluntarily suppressed or activated depending on the task at hand. By applying brief perturbations unexpectedly, both during passive head-on-trunk movements and at rest, we investigated the mechanism of voluntary suppression of resistance to stretch. A physiologically plausible, neuromechanical model of voluntary/reflexive interactions was constructed favoring feedback over reflex gain adjustments. Accordingly, muscle relaxation during imposed head movements is based on sensory feedback similarly to muscle contractions during purposeful movements.
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Affiliation(s)
- Dimitri Anastasopoulos
- Department of Neurorehabilitation, Zurzachcare, Bad Zurzach, Switzerland.,Department of Physiology, University of Athens, Athens, Greece
| | | | - Thomas Mergner
- Department of Neurology, University of Freiburg, Germany
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Marouane E, El Mahmoudi N, Rastoldo G, Péricat D, Watabe I, Lapôtre A, Tonetto A, Xavier F, Dumas O, Chabbert C, Artzner V, Tighilet B. Sensorimotor Rehabilitation Promotes Vestibular Compensation in a Rodent Model of Acute Peripheral Vestibulopathy by Promoting Microgliogenesis in the Deafferented Vestibular Nuclei. Cells 2021; 10:3377. [PMID: 34943885 PMCID: PMC8699190 DOI: 10.3390/cells10123377] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 12/16/2022] Open
Abstract
Acute peripheral vestibulopathy leads to a cascade of symptoms involving balance and gait disorders that are particularly disabling for vestibular patients. Vestibular rehabilitation protocols have proven to be effective in improving vestibular compensation in clinical practice. Yet, the underlying neurobiological correlates remain unknown. The aim of this study was to highlight the behavioural and cellular consequences of a vestibular rehabilitation protocol adapted to a rat model of unilateral vestibular neurectomy. We developed a progressive sensory-motor rehabilitation task, and the behavioural consequences were quantified using a weight-distribution device. This analysis method provides a precise and ecological analysis of posturolocomotor vestibular deficits. At the cellular level, we focused on the analysis of plasticity mechanisms expressed in the vestibular nuclei. The results obtained show that vestibular rehabilitation induces a faster recovery of posturolocomotor deficits during vestibular compensation associated with a decrease in neurogenesis and an increase in microgliogenesis in the deafferented medial vestibular nucleus. This study reveals for the first time a part of the underlying adaptative neuroplasticity mechanisms of vestibular rehabilitation. These original data incite further investigation of the impact of rehabilitation on animal models of vestibulopathy. This new line of research should improve the management of vestibular patients.
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Affiliation(s)
- Emna Marouane
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- BIOSEB ALLCAT Instruments, Couperigne, 13127 Vitrolles, France;
| | - Nada El Mahmoudi
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - Guillaume Rastoldo
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - David Péricat
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, 31400 Toulouse, France;
| | - Isabelle Watabe
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - Agnès Lapôtre
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - Alain Tonetto
- Fédération de Recherche Sciences Chimiques Marseille FR 1739, Pôle 18 PRATIM, CEDEX 03, 13331 Marseille, France;
| | - Frédéric Xavier
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
| | - Olivier Dumas
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
| | - Christian Chabbert
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
| | - Vincent Artzner
- BIOSEB ALLCAT Instruments, Couperigne, 13127 Vitrolles, France;
| | - Brahim Tighilet
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
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Delle Monache S, Indovina I, Zago M, Daprati E, Lacquaniti F, Bosco G. Watching the Effects of Gravity. Vestibular Cortex and the Neural Representation of "Visual" Gravity. Front Integr Neurosci 2021; 15:793634. [PMID: 34924968 PMCID: PMC8671301 DOI: 10.3389/fnint.2021.793634] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Gravity is a physical constraint all terrestrial species have adapted to through evolution. Indeed, gravity effects are taken into account in many forms of interaction with the environment, from the seemingly simple task of maintaining balance to the complex motor skills performed by athletes and dancers. Graviceptors, primarily located in the vestibular otolith organs, feed the Central Nervous System with information related to the gravity acceleration vector. This information is integrated with signals from semicircular canals, vision, and proprioception in an ensemble of interconnected brain areas, including the vestibular nuclei, cerebellum, thalamus, insula, retroinsula, parietal operculum, and temporo-parietal junction, in the so-called vestibular network. Classical views consider this stage of multisensory integration as instrumental to sort out conflicting and/or ambiguous information from the incoming sensory signals. However, there is compelling evidence that it also contributes to an internal representation of gravity effects based on prior experience with the environment. This a priori knowledge could be engaged by various types of information, including sensory signals like the visual ones, which lack a direct correspondence with physical gravity. Indeed, the retinal accelerations elicited by gravitational motion in a visual scene are not invariant, but scale with viewing distance. Moreover, the "visual" gravity vector may not be aligned with physical gravity, as when we watch a scene on a tilted monitor or in weightlessness. This review will discuss experimental evidence from behavioral, neuroimaging (connectomics, fMRI, TMS), and patients' studies, supporting the idea that the internal model estimating the effects of gravity on visual objects is constructed by transforming the vestibular estimates of physical gravity, which are computed in the brainstem and cerebellum, into internalized estimates of virtual gravity, stored in the vestibular cortex. The integration of the internal model of gravity with visual and non-visual signals would take place at multiple levels in the cortex and might involve recurrent connections between early visual areas engaged in the analysis of spatio-temporal features of the visual stimuli and higher visual areas in temporo-parietal-insular regions.
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Affiliation(s)
- Sergio Delle Monache
- UniCamillus—Saint Camillus International University of Health Sciences, Rome, Italy
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Iole Indovina
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | - Myrka Zago
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
- Center for Space Biomedicine, University of Rome “Tor Vergata”, Rome, Italy
- Department of Civil and Computer Engineering, University of Rome “Tor Vergata”, Rome, Italy
| | - Elena Daprati
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
- Center for Space Biomedicine, University of Rome “Tor Vergata”, Rome, Italy
- Department of Systems Medicine, University of Rome “Tor Vergata”, Rome, Italy
| | - Francesco Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
- Center for Space Biomedicine, University of Rome “Tor Vergata”, Rome, Italy
- Department of Systems Medicine, University of Rome “Tor Vergata”, Rome, Italy
| | - Gianfranco Bosco
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
- Center for Space Biomedicine, University of Rome “Tor Vergata”, Rome, Italy
- Department of Systems Medicine, University of Rome “Tor Vergata”, Rome, Italy
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Carriot J, Mackrous I, Cullen KE. Challenges to the Vestibular System in Space: How the Brain Responds and Adapts to Microgravity. Front Neural Circuits 2021; 15:760313. [PMID: 34803615 PMCID: PMC8595211 DOI: 10.3389/fncir.2021.760313] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
In the next century, flying civilians to space or humans to Mars will no longer be a subject of science fiction. The altered gravitational environment experienced during space flight, as well as that experienced following landing, results in impaired perceptual and motor performance-particularly in the first days of the new environmental challenge. Notably, the absence of gravity unloads the vestibular otolith organs such that they are no longer stimulated as they would be on earth. Understanding how the brain responds initially and then adapts to altered sensory input has important implications for understanding the inherent abilities as well as limitations of human performance. Space-based experiments have shown that altered gravity causes structural and functional changes at multiple stages of vestibular processing, spanning from the hair cells of its sensory organs to the Purkinje cells of the vestibular cerebellum. Furthermore, ground-based experiments have established the adaptive capacity of vestibular pathways and neural mechanism that likely underlie this adaptation. We review these studies and suggest that the brain likely uses two key strategies to adapt to changes in gravity: (i) the updating of a cerebellum-based internal model of the sensory consequences of gravity; and (ii) the re-weighting of extra-vestibular information as the vestibular system becomes less (i.e., entering microgravity) and then again more reliable (i.e., return to earth).
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Affiliation(s)
- Jérome Carriot
- Department of Physiology, McGill University, Montreal, QC, Canada
| | | | - Kathleen E. Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
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ROMAGNOLI M, TARANTINO A, GALLI M, ORIGO D. Modulation of vestibulo-ocular reflex gain-symmetry induced by osteopathic manipulations on the fascial system in young healthy subjects: a three-arm randomized controlled trial. GAZZETTA MEDICA ITALIANA ARCHIVIO PER LE SCIENZE MEDICHE 2021. [DOI: 10.23736/s0393-3660.20.04305-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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El Mahmoudi N, Rastoldo G, Marouane E, Péricat D, Watabe I, Tonetto A, Hautefort C, Chabbert C, Sargolini F, Tighilet B. Breaking a dogma: acute anti-inflammatory treatment alters both post-lesional functional recovery and endogenous adaptive plasticity mechanisms in a rodent model of acute peripheral vestibulopathy. J Neuroinflammation 2021; 18:183. [PMID: 34419105 PMCID: PMC8380392 DOI: 10.1186/s12974-021-02222-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/19/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Due to their anti-inflammatory action, corticosteroids are the reference treatment for brain injuries and many inflammatory diseases. However, the benefits of acute corticotherapy are now being questioned, particularly in the case of acute peripheral vestibulopathies (APV), characterized by a vestibular syndrome composed of sustained spinning vertigo, spontaneous ocular nystagmus and oscillopsia, perceptual-cognitive, posturo-locomotor, and vegetative disorders. We assessed the effectiveness of acute corticotherapy, and the functional role of acute inflammation observed after sudden unilateral vestibular loss. METHODS We used the rodent model of unilateral vestibular neurectomy, mimicking the syndrome observed in patients with APV. We treated the animals during the acute phase of the vestibular syndrome, either with placebo or methylprednisolone, an anti-inflammatory corticosteroid. At the cellular level, impacts of methylprednisolone on endogenous plasticity mechanisms were assessed through analysis of cell proliferation and survival, glial reactions, neuron's membrane excitability, and stress marker. At the behavioral level, vestibular and posturo-locomotor functions' recovery were assessed with appropriate qualitative and quantitative evaluations. RESULTS We observed that acute treatment with methylprednisolone significantly decreases glial reactions, cell proliferation and survival. In addition, stress and excitability markers were significantly impacted by the treatment. Besides, vestibular syndrome's intensity was enhanced, and vestibular compensation delayed under acute methylprednisolone treatment. CONCLUSIONS We show here, for the first time, that acute anti-inflammatory treatment alters the expression of the adaptive plasticity mechanisms in the deafferented vestibular nuclei and generates enhanced and prolonged vestibular and postural deficits. These results strongly suggest a beneficial role for acute endogenous neuroinflammation in vestibular compensation. They open the way to a change in dogma for the treatment and therapeutic management of vestibular patients.
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Affiliation(s)
- Nada El Mahmoudi
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
- Centre Saint-Charles, Aix-Marseille Université CNRS, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Guillaume Rastoldo
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
- Centre Saint-Charles, Aix-Marseille Université CNRS, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Emna Marouane
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
- Centre Saint-Charles, Aix-Marseille Université CNRS, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - David Péricat
- Institut de Pharmacologie Et de Biologie Structurale, Université de Toulouse Paul Sabatier-CNRS, Toulouse, France
| | - Isabelle Watabe
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
- Centre Saint-Charles, Aix-Marseille Université CNRS, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Alain Tonetto
- Centrale Marseille, FSCM (FR 1739), PRATIM, Aix Marseille Université-CNRS, 13397, Marseille, France
| | - Charlotte Hautefort
- Department of Head and Neck Surgery, Lariboisière University Hospital, Paris, France
| | - Christian Chabbert
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
- Centre Saint-Charles, Aix-Marseille Université CNRS, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
- GDR Physiopathologie Vestibulaire-Unité GDR2074 CNRS, Marseille, France
| | - Francesca Sargolini
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France
| | - Brahim Tighilet
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint Charles, Case C; 3 Place Victor Hugo, 13331, Marseille Cedex 03, France.
- GDR Physiopathologie Vestibulaire-Unité GDR2074 CNRS, Marseille, France.
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Facchini J, Rastoldo G, Xerri C, Péricat D, El Ahmadi A, Tighilet B, Zennou-Azogui Y. Unilateral vestibular neurectomy induces a remodeling of somatosensory cortical maps. Prog Neurobiol 2021; 205:102119. [PMID: 34246703 DOI: 10.1016/j.pneurobio.2021.102119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 06/23/2021] [Accepted: 07/06/2021] [Indexed: 10/20/2022]
Abstract
Unilateral Vestibular Neurectomy (UVN) induces a postural syndrome whose compensation over time is underpinned by multimodal sensory substitution processes. However, at a chronic stage of compensation, UVN rats exhibit an enduring postural asymmetry expressed by an increase in the body weight on the ipsilesional paws. Given the anatomo-functional links between the vestibular nuclei and the primary somatosensory cortex (S1), we explored the interplay of vestibular and somatosensory cortical inputs following acute and chronic UVN. We determined whether the enduring imbalance in tactilo-plantar inputs impacts response properties of S1 cortical neurons and organizational features of somatotopic maps. We performed electrophysiological mapping of the hindpaw cutaneous representations in S1, immediately and one month after UVN. In parallel, we assessed the posturo-locomotor imbalance during the compensation process. UVN immediately induces an expansion of the cortical neuron cutaneous receptive fields (RFs) leading to a partial dedifferentiation of somatotopic maps. This effect was demonstrated for the ventral skin surface representations and was greater on the contralesional hindpaw for which the neuronal threshold to skin pressure strongly decreased. The RF enlargement was amplified for the representation of the ipsilesional hindpaw in relation to persistent postural asymmetries, but was transitory for the contralesional one. Our study shows, for the first time, that vestibular inputs exert a modulatory influence on S1 neuron's cutaneous responses. The lesion-induced cortical malleability highlights the influence of vestibular inputs on tactile processing related to postural control.
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Affiliation(s)
- Justine Facchini
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives (LNC), UMR 7291, Marseille, France
| | - Guillaume Rastoldo
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives (LNC), UMR 7291, Marseille, France
| | - Christian Xerri
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives (LNC), UMR 7291, Marseille, France
| | - David Péricat
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives (LNC), UMR 7291, Marseille, France
| | - Abdessadek El Ahmadi
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives (LNC), UMR 7291, Marseille, France
| | - Brahim Tighilet
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives (LNC), UMR 7291, Marseille, France.
| | - Yoh'i Zennou-Azogui
- Aix Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives (LNC), UMR 7291, Marseille, France.
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Samartsev IN, Zhivolupov SA. [The significance of neuroplastic mechanisms in compensation of statodynamic impairments during vestibular disorders]. Zh Nevrol Psikhiatr Im S S Korsakova 2021; 121:165-172. [PMID: 34184494 DOI: 10.17116/jnevro2021121051165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The process of balance restoration in patients with the vestibular disorders is known as «vestibular compensation». It is obvious nowadays that this phenomenon is very complex and is associated with the deep brain neuroplastic changes involving reinnervation, habituation and adaptation. The research of the last decades has shown some fundamental physiologic mechanisms that form the basis of neuroplasticity, establish the staging of ongoing transformations and analyze the opportunity to improve and/or accelerate vestibular compensation with the help of vestibular rehabilitation and contemporary medications such as betaserc long.
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Affiliation(s)
- I N Samartsev
- Kirov Military Medical Academy, St. Petersburg, Russia
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21
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Zobeiri OA, Ostrander B, Roat J, Agrawal Y, Cullen KE. Loss of peripheral vestibular input alters the statistics of head movement experienced during natural self-motion. J Physiol 2021; 599:2239-2254. [PMID: 33599981 DOI: 10.1113/jp281183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 02/16/2021] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS Sensory systems are adapted to the statistical structure of natural stimuli, thereby optimizing neural coding. Head motion during natural activities is first sensed and then processed by central vestibulo-motor pathways to influence subsequent behaviour, thereby establishing a feedback loop. To investigate the role of this vestibular feedback on the statistical structure of the head movements, we compared head movements in patients with unilateral vestibular loss and healthy controls. We show that the loss of vestibular feedback substantially alters the statistical structure of head motion for activities that require rapid online feedback control and predict this change by modelling the effects of increased movement variability. Our findings suggest that, following peripheral vestibular loss, changes in the reliability of the sensory input to central pathways impact the statistical structure of head motion during voluntary behaviours. ABSTRACT It is widely believed that sensory systems are adapted to optimize neural coding of their natural stimuli. Recent evidence suggests that this is the case for the vestibular system, which senses head movement and contributes to essential functions ranging from the most automatic reflexes to voluntary motor control. During everyday behaviours, head motion is sensed by the vestibular system. In turn, this sensory feedback influences subsequent behaviour, raising the questions of whether and how real-time feedback provided by the vestibular system alters the statistical structure of head movements. We predicted that a reduction in vestibular feedback would alter head movement statistics, particularly for tasks reliant on rapid vestibular feedback. To test this proposal, we recorded six-dimensional head motion in patients with variable degrees of unilateral vestibular loss during standard balance and gait tasks, as well as dynamic self-paced activities. While distributions of linear accelerations and rotational velocities were comparable for patients and age-matched healthy controls, comparison of power spectra revealed significant differences during more dynamic and challenging activities. Specifically, consistent with our prediction, head movement power spectra were significantly altered in patients during two tasks that required rapid online vestibular feedback: active repetitive jumping and walking on foam. Using computational methods, we analysed concurrently measured torso motion and identified increases in head-torso movement variability. Taken together, our results demonstrate that vestibular loss significantly alters head movement statistics and further suggest that increased variability and impaired feedback to internal models required for accurate motor control contribute to the observed changes.
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Affiliation(s)
- Omid A Zobeiri
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Benjamin Ostrander
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jessica Roat
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yuri Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, USA
| | - Kathleen E Cullen
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, USA
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Wagner AR, Akinsola O, Chaudhari AMW, Bigelow KE, Merfeld DM. Measuring Vestibular Contributions to Age-Related Balance Impairment: A Review. Front Neurol 2021; 12:635305. [PMID: 33633678 PMCID: PMC7900546 DOI: 10.3389/fneur.2021.635305] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/18/2021] [Indexed: 12/16/2022] Open
Abstract
Aging is associated with progressive declines in both the vestibular and human balance systems. While vestibular lesions certainly contribute to imbalance, the specific contributions of age-related vestibular declines to age-related balance impairment is poorly understood. This gap in knowledge results from the absence of a standardized method for measuring age-related changes to the vestibular balance pathways. The purpose of this manuscript is to provide an overview of the existing body of literature as it pertains to the methods currently used to infer vestibular contributions to age-related imbalance.
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Affiliation(s)
- Andrew R. Wagner
- School of Health and Rehabilitation Science, The Ohio State University, Columbus, OH, United States
- Department of Otolaryngology—Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
| | - Olaoluwa Akinsola
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, United States
| | - Ajit M. W. Chaudhari
- School of Health and Rehabilitation Science, The Ohio State University, Columbus, OH, United States
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, United States
| | - Kimberly E. Bigelow
- Department of Mechanical and Aerospace Engineering, University of Dayton, Dayton, OH, United States
| | - Daniel M. Merfeld
- School of Health and Rehabilitation Science, The Ohio State University, Columbus, OH, United States
- Department of Otolaryngology—Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
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23
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Abstract
As we actively explore the environment, our motion relative to the world stimulates numerous sensory systems. Notably, proprioceptors provide feedback about body and limb position, while the vestibular system detects and encodes head motion. When the vestibular system is functioning normally, we are unaware of a distinct sensation because vestibular information is integrated with proprioceptive and other sensory inputs to generate our sense of motion. However, patients with vestibular sensory loss experience impairments that provide important insights into the function of this essential sensory system. For these patients, everyday activities such as walking become difficult because even small head movements can produce postural and perceptual instability. This review describes recent research demonstrating how the proprioceptive and vestibular systems effectively work together to provide us with our “6th sense” during everyday activities, and in particular considers the neural computations underlying the brain’s predictive sensing of head movement during voluntary self-motion.
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Affiliation(s)
- Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA
- Department of Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, United States
- Department of Neuroscience, Johns Hopkins University, Baltimore, United States
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, United States
| | - Omid A Zobeiri
- Department of Biomedical Engineering, McGill University, Montréal, Canada
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24
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Zobeiri OA, Mischler GM, King SA, Lewis RF, Cullen KE. Effects of vestibular neurectomy and neural compensation on head movements in patients undergoing vestibular schwannoma resection. Sci Rep 2021; 11:517. [PMID: 33436776 PMCID: PMC7804855 DOI: 10.1038/s41598-020-79756-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023] Open
Abstract
The vestibular system is vital for maintaining balance and stabilizing gaze and vestibular damage causes impaired postural and gaze control. Here we examined the effects of vestibular loss and subsequent compensation on head motion kinematics during voluntary behavior. Head movements were measured in vestibular schwannoma patients before, and then 6 weeks and 6 months after surgical tumor removal, requiring sectioning of the involved vestibular nerve (vestibular neurectomy). Head movements were recorded in six dimensions using a small head-mounted sensor while patients performed the Functional Gait Assessment (FGA). Kinematic measures differed between patients (at all three time points) and normal subjects on several challenging FGA tasks, indicating that vestibular damage (caused by the tumor or neurectomy) alters head movements in a manner that is not normalized by central compensation. Kinematics measured at different time points relative to vestibular neurectomy differed substantially between pre-operative and 6-week post-operative states but changed little between 6-week and > 6-month post-operative states, demonstrating that compensation affecting head kinematics is relatively rapid. Our results indicate that quantifying head kinematics during self-generated gait tasks provides valuable information about vestibular damage and compensation, suggesting that early changes in patient head motion strategy may be maladaptive for long-term vestibular compensation.
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Affiliation(s)
- Omid A Zobeiri
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Gavin M Mischler
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA
| | - Susan A King
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
- Departments of Otolaryngology and Neurology, Harvard Medical School, Boston, MA, USA
| | - Richard F Lewis
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
- Departments of Otolaryngology and Neurology, Harvard Medical School, Boston, MA, USA
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, USA.
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA.
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, USA.
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25
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Vestibular failure managed with osteopathic manipulative treatment: A report of two cases. J Bodyw Mov Ther 2020; 24:59-62. [DOI: 10.1016/j.jbmt.2020.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 01/29/2020] [Accepted: 02/17/2020] [Indexed: 11/17/2022]
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26
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Wagner AR, Schubert MC. Evidence a shared mechanism mediates ipsi- and contralesional compensatory saccades and gait after unilateral vestibular deafferentation. J Neurophysiol 2020; 123:1486-1495. [DOI: 10.1152/jn.00585.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The study objective was to understand how the contralesional labyrinth contributes to gaze and gait stability after unilateral vestibular deafferentation (UVD). Head impulse testing (vHIT) was completed in 37 individuals [22 women (59%); age 52.13 ± 11.59 yr, mean ± SD] with UVD from vestibular schwannoma resection. Compensatory saccades (CS) and vestibulo-ocular reflex (VOR) gain were analyzed for both ipsilesional and contralesional impulses. Gait speed (10-m walk test) and endurance (2-min walk test) were collected for 35 individuals. CS were recruited during contralesional head rotation regardless of VOR gain on either the ipsilesional [ρ = 0.21 (−0.14, 0.57); Spearman rank (95% confidence interval)] or contralesional side [ρ = −0.04 (−0.42, 0.35)]. Additionally, the latency of these CS (151.19 ± 52.41 ms) was similar to that of CS generated during ipsilesional rotation (165.65 ± 21.62 ms; P = 0.159). CS recruited during ipsilesional vHIT were of a higher velocity ( P < 0.001) and greater frequency ( P < 0.001) compared with contralesional CS. VOR gain asymmetry was significantly correlated with gait speed [ρ = −0.37 (−0.73, −0.01)], yet individual VOR gain was not correlated [ipsilesional: ρ = 0.17 (−0.20, 0.55); contralesional: ρ = −0.18 (−0.52, 0.15)]. Our data reveal CS are recruited at similar latencies without correlation to VOR gain or direction of head rotation, and that the central integration of ipsilesional and contralesional vestibular afference correlates with gait. Together, our data suggest the brain considers vestibular afference from both sides when generating related behavioral output after UVD. NEW & NOTEWORTHY After unilateral vestibular deafferentation, compensatory saccades (CS) have similar latencies regardless of the direction of head rotation, and those CS generated during contralesional head rotation are unrelated to extent of vestibular loss. Additionally, the extent of asymmetry in residual vestibular function, not the extent of vestibular loss, correlates with gait speed. Our data suggest a common mechanism is responsible for the generation of CS and restoration of gait speed in vestibular compensation.
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Affiliation(s)
- Andrew R. Wagner
- College of Medicine, School of Health and Rehabilitation Science, The Ohio State University, Columbus, Ohio
| | - Michael C. Schubert
- Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology - Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Physical Medicine and Rehabilitation, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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27
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Rassaian N, Sadeghi NG, Sabetazad B, McNerney KM, Burkard RF, Sadeghi SG. Using Unidirectional Rotations to Improve Vestibular System Asymmetry in Patients with Vestibular Dysfunction. J Vis Exp 2019. [PMID: 31524871 DOI: 10.3791/60053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The vestibular system provides information about head movement and mediates reflexes that contribute to balance control and gaze stabilization during daily activities. Vestibular sensors are located in the inner ear on both sides of the head and project to the vestibular nuclei in the brainstem. Vestibular dysfunction is often due to an asymmetry between input from the two sides. This results in asymmetrical neural inputs from the two ears, which can produce an illusion of rotation, manifested as vertigo. The vestibular system has an impressive capacity for compensation, which serves to rebalance how asymmetrical information from the sensory end organs on both sides is processed at the central level. To promote compensation, various rehabilitation programs are used in the clinic; however, they primarily use exercises that improve multisensory integration. Recently, visual-vestibular training has also been used to improve the vestibulo-ocular reflex (VOR) in animals with compensated unilateral lesions. Here, a new method is introduced for rebalancing the vestibular activity on both sides in human subjects. This method consists of five unidirectional rotations in the dark (peak velocity of 320°/s) toward the weaker side. The efficacy of this method was shown in a sequential, double-blinded clinical trial in 16 patients with VOR asymmetry (measured by the directional preponderance in response to sinusoidal rotations). In most cases, VOR asymmetry decreased after a single session, reached normal values within the first two sessions in one week, and the effects lasted up to 6 weeks. The rebalancing effect is due to both an increase in VOR response from the weaker side and a decrease in response from the stronger side. The findings suggest that unidirectional rotation can be used as a supervised rehabilitation method to reduce VOR asymmetry in patients with longstanding vestibular dysfunction.
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Affiliation(s)
- Nayer Rassaian
- Department of Physiology, Shahid Beheshti University of Medical Sciences and Health Services
| | - Navid G Sadeghi
- Department of Physiology, Shahid Beheshti University of Medical Sciences and Health Services
| | | | | | - Robert F Burkard
- Department of Rehabilitation Science, School of Public Health and Health Professions, State University of New York at Buffalo
| | - Soroush G Sadeghi
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo;
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28
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Mackrous I, Carriot J, Jamali M, Cullen KE. Cerebellar Prediction of the Dynamic Sensory Consequences of Gravity. Curr Biol 2019; 29:2698-2710.e4. [PMID: 31378613 DOI: 10.1016/j.cub.2019.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/19/2019] [Accepted: 07/01/2019] [Indexed: 12/29/2022]
Abstract
As we go about our everyday activities, our brain computes accurate estimates of both our motion relative to the world and our orientation relative to gravity. However, how the brain then accounts for gravity as we actively move and interact with our environment is not yet known. Here, we provide evidence that, although during passive movements, individual cerebellar output neurons encode representations of head motion and orientation relative to gravity, these gravity-driven responses are cancelled when head movement is a consequence of voluntary generated movement. In contrast, the gravity-driven responses of primary otolith and semicircular canal afferents remain intact during both active and passive self-motion, indicating the attenuated responses of central neurons are not inherited from afferent inputs. Taken together, our results are consistent with the view that the cerebellum builds a dynamic prediction (e.g., internal model) of the sensory consequences of gravity during active self-motion, which in turn enables the preferential encoding of unexpected motion to ensure postural and perceptual stability.
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Affiliation(s)
- Isabelle Mackrous
- Department of Physiology, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montréal, QC H3G 1Y6, Canada.
| | - Jerome Carriot
- Department of Physiology, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montréal, QC H3G 1Y6, Canada.
| | - Mohsen Jamali
- Department of Physiology, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montréal, QC H3G 1Y6, Canada.
| | - Kathleen E Cullen
- Department of Physiology, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montréal, QC H3G 1Y6, Canada; Department of Biomedical Engineering, Johns Hopkins University, Rm. 720, Ross Building, 720 Rutland Avenue, Baltimore, MD 21205, USA.
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29
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Mackrous I, Carriot J, Simoneau M. Learning to use vestibular sense for spatial updating is context dependent. Sci Rep 2019; 9:11154. [PMID: 31371770 PMCID: PMC6671975 DOI: 10.1038/s41598-019-47675-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 07/22/2019] [Indexed: 11/09/2022] Open
Abstract
As we move, perceptual stability is crucial to successfully interact with our environment. Notably, the brain must update the locations of objects in space using extra-retinal signals. The vestibular system is a strong candidate as a source of information for spatial updating as it senses head motion. The ability to use this cue is not innate but must be learned. To date, the mechanisms of vestibular spatial updating generalization are unknown or at least controversial. In this paper we examine generalization patterns within and between different conditions of vestibular spatial updating. Participants were asked to update the position of a remembered target following (offline) or during (online) passive body rotation. After being trained on a single spatial target position within a given task, we tested generalization of performance for different spatial targets and an unpracticed spatial updating task. The results demonstrated different patterns of generalization across the workspace depending on the task. Further, no transfer was observed from the practiced to the unpracticed task. We found that the type of mechanism involved during learning governs generalization. These findings provide new knowledge about how the brain uses vestibular information to preserve its spatial updating ability.
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Affiliation(s)
| | - Jérôme Carriot
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Martin Simoneau
- Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS), Québec, QC, Canada. .,Département de kinésiologie, Faculté de médecine, Université Laval, Québec, QC, Canada.
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30
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Cassel R, Bordiga P, Carcaud J, Simon F, Beraneck M, Le Gall A, Benoit A, Bouet V, Philoxene B, Besnard S, Watabe I, Pericat D, Hautefort C, Assie A, Tonetto A, Dyhrfjeld-Johnsen J, Llorens J, Tighilet B, Chabbert C. Morphological and functional correlates of vestibular synaptic deafferentation and repair in a mouse model of acute-onset vertigo. Dis Model Mech 2019; 12:dmm.039115. [PMID: 31213478 PMCID: PMC6679379 DOI: 10.1242/dmm.039115] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 06/06/2019] [Indexed: 12/25/2022] Open
Abstract
Damage to cochlear primary afferent synapses has been shown to be a key factor in various auditory pathologies. Similarly, the selective lesioning of primary vestibular synapses might be an underlying cause of peripheral vestibulopathies that cause vertigo and dizziness, for which the pathophysiology is currently unknown. To thoroughly address this possibility, we selectively damaged the synaptic contacts between hair cells and primary vestibular neurons in mice through the transtympanic administration of a glutamate receptor agonist. Using a combination of histological and functional approaches, we demonstrated four key findings: (1) selective synaptic deafferentation is sufficient to generate acute vestibular syndrome with characteristics similar to those reported in patients; (2) the reduction of the vestibulo-ocular reflex and posturo-locomotor deficits mainly depends on spared synapses; (3) damaged primary vestibular synapses can be repaired over the days and weeks following deafferentation; and (4) the synaptic repair process occurs through the re-expression and re-pairing of synaptic proteins such as CtBP2 and SHANK-1. Primary synapse repair might contribute to re-establishing the initial sensory network. Deciphering the molecular mechanism that supports synaptic repair could offer a therapeutic opportunity to rescue full vestibular input and restore gait and balance in patients. Summary: The molecular rearrangements of the synaptic proteins that accompany the deafferentation and subsequent reafferentation of the inner ear sensors following an excitotoxic insult are demonstrated for the first time.
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Affiliation(s)
- Raphaelle Cassel
- Aix Marseille Université, CNRS, UMR 7260, Laboratoire de Neurosciences Sensorielles et Cognitives - Equipe Physiopathologie et Thérapie des Désordres Vestibulaires, Marseille, 13000 France
| | - Pierrick Bordiga
- Aix Marseille Université, CNRS, UMR 7260, Laboratoire de Neurosciences Sensorielles et Cognitives - Equipe Physiopathologie et Thérapie des Désordres Vestibulaires, Marseille, 13000 France
| | - Julie Carcaud
- Integrative Neuroscience and Cognition Center, UMR 8002, CNRS, 75006 Paris, France
| | - François Simon
- Integrative Neuroscience and Cognition Center, UMR 8002, CNRS, 75006 Paris, France.,Sorbonne Paris Cité, Université Paris Descartes, 75006 Paris, France
| | - Mathieu Beraneck
- Integrative Neuroscience and Cognition Center, UMR 8002, CNRS, 75006 Paris, France.,Sorbonne Paris Cité, Université Paris Descartes, 75006 Paris, France
| | | | | | | | | | | | - Isabelle Watabe
- Aix Marseille Université, CNRS, UMR 7260, Laboratoire de Neurosciences Sensorielles et Cognitives - Equipe Physiopathologie et Thérapie des Désordres Vestibulaires, Marseille, 13000 France
| | - David Pericat
- Aix Marseille Université, CNRS, UMR 7260, Laboratoire de Neurosciences Sensorielles et Cognitives - Equipe Physiopathologie et Thérapie des Désordres Vestibulaires, Marseille, 13000 France
| | | | - Axel Assie
- Aix-Marseille Université, CNRS, Centrale Marseille, FSCM (FR1739), PRATIM, Marseille, 13000 France
| | - Alain Tonetto
- Aix-Marseille Université, CNRS, Centrale Marseille, FSCM (FR1739), PRATIM, Marseille, 13000 France
| | | | | | - Brahim Tighilet
- Aix Marseille Université, CNRS, UMR 7260, Laboratoire de Neurosciences Sensorielles et Cognitives - Equipe Physiopathologie et Thérapie des Désordres Vestibulaires, Marseille, 13000 France
| | - Christian Chabbert
- Aix Marseille Université, CNRS, UMR 7260, Laboratoire de Neurosciences Sensorielles et Cognitives - Equipe Physiopathologie et Thérapie des Désordres Vestibulaires, Marseille, 13000 France
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31
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Cullen KE. Vestibular processing during natural self-motion: implications for perception and action. Nat Rev Neurosci 2019; 20:346-363. [PMID: 30914780 PMCID: PMC6611162 DOI: 10.1038/s41583-019-0153-1] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
How the brain computes accurate estimates of our self-motion relative to the world and our orientation relative to gravity in order to ensure accurate perception and motor control is a fundamental neuroscientific question. Recent experiments have revealed that the vestibular system encodes this information during everyday activities using pathway-specific neural representations. Furthermore, new findings have established that vestibular signals are selectively combined with extravestibular information at the earliest stages of central vestibular processing in a manner that depends on the current behavioural goal. These findings have important implications for our understanding of the brain mechanisms that ensure accurate perception and behaviour during everyday activities and for our understanding of disorders of vestibular processing.
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Affiliation(s)
- Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
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32
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Sadeghi NG, Sabetazad B, Rassaian N, Sadeghi SG. Rebalancing the Vestibular System by Unidirectional Rotations in Patients With Chronic Vestibular Dysfunction. Front Neurol 2019; 9:1196. [PMID: 30723455 PMCID: PMC6349764 DOI: 10.3389/fneur.2018.01196] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 12/31/2018] [Indexed: 11/20/2022] Open
Abstract
Introduction: Vestibular dysfunction is a common disorder that results in debilitating symptoms. Even after full compensation, the vestibulo-ocular reflex (VOR) could be further improved by using rehabilitation exercises and visual-vestibular adaptation. We hypothesized that in patients with asymmetric vestibular function, the system could be rebalanced by unidirectional rotations toward the weaker side (i.e., a pure vestibular stimulation). Methods: Sixteen subjects (5 female and 11 male, 43.2 ± 17.0 years old) with chronic vestibular dysfunction that was non-responsive to other types of medical treatment were recruited for the study (ClinicalTrials.gov Identifier: NCT01080430). Subjects had VOR asymmetry quantified by an abnormal directional preponderance (DP) with rotation test and no previous history of central vestibular problems or fluctuating peripheral vestibular disorders. They participated either in the short-term study (one session) or the long-term study (7 visits over 5 weeks). Rehabilitation consisted of five trapezoid unidirectional rotations (peak velocity of 320°/s) toward the weaker side. Care was taken to slowly stop the rotation in order to avoid stimulation in the opposite direction during deceleration. To study the short-term effect, VOR responses were measured before and 10, 40, and 70 min after a single unidirectional rotational rehabilitation session. For long-term effects, the VOR gain was measured before and 70min after rehabilitation in each session. Results: We observed a significant decrease in VOR asymmetry even 10 min after one rehabilitation session (short-term study). With consecutive rehabilitation sessions in the long-term study, DP further decreased to reach normal values during the first 2 sessions and only one subjects required further rehabilitation after week 4. This change in DP was due to an increase in responses during rotations toward the weaker side and a decrease in VOR responses during rotations in the other direction. Conclusion: Our results show that unidirectional rotation can reduce the VOR imbalance and asymmetry in patients with previously compensated vestibular dysfunction and could be used as an effective supervised method for vestibular rehabilitation even in patients with longstanding vestibular dysfunction.
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Affiliation(s)
- Navid G Sadeghi
- Department of Physiology, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
| | - Bardia Sabetazad
- Audiology and Dizziness Center, Day General Hospital, Tehran, Iran
| | - Nayer Rassaian
- Department of Physiology, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
| | - Soroush G Sadeghi
- Department of Communicative Disorders and Sciences, Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, United States
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33
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Rasman BG, Forbes PA, Tisserand R, Blouin JS. Sensorimotor Manipulations of the Balance Control Loop-Beyond Imposed External Perturbations. Front Neurol 2018; 9:899. [PMID: 30416481 PMCID: PMC6212554 DOI: 10.3389/fneur.2018.00899] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/03/2018] [Indexed: 12/22/2022] Open
Abstract
Standing balance relies on the integration of multiple sensory inputs to generate the motor commands required to stand. Mechanical and sensory perturbations elicit compensatory postural responses that are interpreted as a window into the sensorimotor processing involved in balance control. Popular methods involve imposed external perturbations that disrupt the control of quiet stance. Although these approaches provide critical information on how the balance system responds to external disturbances, the control mechanisms involved in correcting for these errors may differ from those responsible for the regulation of quiet standing. Alternative approaches use manipulations of the balance control loop to alter the relationship between sensory and motor cues. Coupled with imposed perturbations, these manipulations of the balance control loop provide unique opportunities to reveal how sensory and motor signals are integrated to control the upright body. In this review, we first explore imposed perturbation approaches that have been used to investigate the neural control of standing balance. We emphasize imposed perturbations that only elicit balance responses when the disturbing stimuli are relevant to the balance task. Next, we highlight manipulations of the balance control loop that, when carefully implemented, replicate and/or alter the sensorimotor dynamics of quiet standing. We further describe how manipulations of the balance control loop can be used in combination with imposed perturbations to characterize mechanistic principles underlying the control of standing balance. We propose that recent developments in the use of robotics and sensory manipulations will continue to enable new possibilities for simulating and/or altering the sensorimotor control of standing beyond compensatory responses to imposed external perturbations.
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Affiliation(s)
- Brandon G. Rasman
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Patrick A. Forbes
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, Netherlands
| | - Romain Tisserand
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, BC, Canada
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Muntaseer Mahfuz M, Schubert MC, Figtree WVC, Todd CJ, Migliaccio AA. Human Vestibulo-Ocular Reflex Adaptation Training: Time Beats Quantity. J Assoc Res Otolaryngol 2018; 19:729-739. [PMID: 30251187 DOI: 10.1007/s10162-018-00689-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/04/2018] [Indexed: 01/08/2023] Open
Abstract
The vestibulo-ocular reflex (VOR) is the main gaze stabilising system during rapid head movements. The VOR is highly plastic and its gain (eye/head velocity) can be increased via training that induces an incrementally increasing retinal image slip error signal to drive VOR adaptation. Using the unilateral incremental VOR adaptation technique and horizontal active head impulses as the vestibular stimulus, we sought to determine the factors important for VOR adaptation including: the total training time, ratio and number of head impulses to each side (adapting and non-adapting sides; the adapting side was pseudo-randomised left or right) and exposure time to the visual target during each head impulse. We tested 11 normal subjects, each over 5 separate sessions and training protocols. The basic training protocol (protocol one) consisted of unilateral incremental VOR adaptation training lasting 15 min with the ratio of head impulses to each side 1:1. Each protocol varied from the basic. For protocol two, the ratio of impulses were in favour of the adapting side by 2:1. For protocol three, all head impulses were towards the adapting side and the training only lasted 7.5 min. For protocol four, all impulses were towards the adapting side and lasted 15 min. For protocol five, all head impulses were to the adapting side and the exposure time to the visual target during each impulse was doubled. We measured the active and passive VOR gains before and after the training. Albeit with small sample size, our data suggest that the total training time and the visual target exposure time for each head impulse affected adaptation, whereas the total number and repetition rate of head impulses did not. These data have implications for vestibular rehabilitation, suggesting that quality and duration of VOR adaptation exercises are more important than rapid repetition of exercises.
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Affiliation(s)
- M Muntaseer Mahfuz
- Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick, NSW, 2031, Australia
- University of New South Wales, Sydney, NSW, 2033, Australia
| | - Michael C Schubert
- Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - William V C Figtree
- Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick, NSW, 2031, Australia
- University of New South Wales, Sydney, NSW, 2033, Australia
| | - Christopher J Todd
- Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick, NSW, 2031, Australia
- University of New South Wales, Sydney, NSW, 2033, Australia
| | - Americo A Migliaccio
- Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick, NSW, 2031, Australia.
- University of New South Wales, Sydney, NSW, 2033, Australia.
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, 21205, USA.
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Plasticity within excitatory and inhibitory pathways of the vestibulo-spinal circuitry guides changes in motor performance. Sci Rep 2017; 7:853. [PMID: 28405011 PMCID: PMC5429812 DOI: 10.1038/s41598-017-00956-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/20/2017] [Indexed: 11/09/2022] Open
Abstract
Investigations of behaviors with well-characterized circuitry are required to understand how the brain learns new motor skills and ensures existing behaviors remain appropriately calibrated over time. Accordingly, here we recorded from neurons within different sites of the vestibulo-spinal circuitry of behaving macaque monkeys during temporally precise activation of vestibular afferents. Behaviorally relevant patterns of vestibular nerve activation generated a rapid and substantial decrease in the monosynaptic responses recorded at the first central stage of processing from neurons receiving direct input from vestibular afferents within minutes, as well as a decrease in the compensatory reflex response that lasted up to 8 hours. In contrast, afferent responses to this same stimulation remained constant, indicating that plasticity was not induced at the level of the periphery but rather at the afferent-central neuron synapse. Strikingly, the responses of neurons within indirect brainstem pathways also remained constant, even though the efficacy of their central input was significantly reduced. Taken together, our results show that rapid plasticity at the first central stage of vestibulo-spinal pathways can guide changes in motor performance, and that complementary plasticity on the same millisecond time scale within inhibitory vestibular nuclei networks contributes to ensuring a relatively robust behavioral output.
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Grasso C, Li Volsi G, Cataldo E, Manzoni D, Barresi M. Effects of bicuculline application on the somatosensory responses of secondary vestibular neurons. Neuroscience 2016; 335:122-33. [PMID: 27579770 DOI: 10.1016/j.neuroscience.2016.08.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/19/2016] [Accepted: 08/21/2016] [Indexed: 01/05/2023]
Abstract
Limb somatosensory signals modify the discharge of vestibular neurons and elicit postural reflexes, which stabilize the body position. The aim of this study was to investigate the contribution of the γ-amino-butyric-acid (GABA) to the responsiveness of vestibular neurons to somatosensory inputs. The activity of 128 vestibular units was recorded in anesthetized rats in resting conditions and during sinusoidal foreleg rotation around the elbow or shoulder joints (0.026-0.625Hz, 45° peak amplitude). None of the recorded units was influenced by elbow rotation, while 40% of them responded to shoulder rotation. The selective GABAA antagonist receptor, bicuculline methiodine (BIC), was applied by microiontophoresis on single vestibular neurons and the changes in their activity at rest and during somatosensory stimulation was studied. In about half of cells the resting activity increased after the BIC application: 75% of these neurons showed also an increased response to somatosensory inputs whereas 17% exhibited a decrease. Changes in responsiveness in both directions were detected also in the units whose resting activity was not influenced by BIC. These data suggest that the responses of vestibular neurons to somatosensory inputs are modulated by GABA through a tonic release, which modifies the membrane response to the synaptic current. It is also possible that a phasic release of GABA occurs during foreleg rotation, shaping the stimulus-elicited current passing through the membrane. If this is the case, the changes in the relative position of body segments would modify the GABA release inducing changes in the vestibular reflexes and in learning processes that modify their spatio-temporal development.
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Affiliation(s)
- C Grasso
- Department of Biomedical and Biotechnological Sciences - Section of Physiology, University of Catania, I-95125 Catania, Italy
| | - G Li Volsi
- Department of Biomedical and Biotechnological Sciences - Section of Physiology, University of Catania, I-95125 Catania, Italy
| | - E Cataldo
- Department of Physics, University of Pisa, I-56127 Pisa, Italy
| | - D Manzoni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, I-56127 Pisa, Italy
| | - M Barresi
- Department of Drug Sciences, University of Catania, I-95125 Catania, Italy.
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Newlands SD, Wei M, Morgan D, Luan H. Responses of non-eye-movement central vestibular neurons to sinusoidal yaw rotation in compensated macaques after unilateral semicircular canal plugging. J Neurophysiol 2016; 116:1871-1884. [PMID: 27489364 DOI: 10.1152/jn.00212.2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 07/27/2016] [Indexed: 01/24/2023] Open
Abstract
After vestibular labyrinth injury, behavioral measures of vestibular performance recover to variable degrees (vestibular compensation). Central neuronal responses after unilateral labyrinthectomy (UL), which eliminates both afferent resting activity and sensitivity to movement, have been well-studied. However, unilateral semicircular canal plugging (UCP), which attenuates angular-velocity detection while leaving afferent resting activity intact, has not been extensively studied. The current study reports response properties of yaw-sensitive non-eye-movement rhesus macaque vestibular neurons after compensation from UCP. The responses at a series of frequencies (0.1-2 Hz) and peak velocities (15-210°/s) were compared between neurons recorded before and at least 6 wk after UCP. The gain (sp/s/°/s) of central type I neurons (responding to ipsilateral yaw rotation) on the side of UCP was reduced relative to normal controls at 0.5 Hz, ±60°/s [0.48 ± 0.30 (SD) normal, 0.32 ± 0.15 ipsilesion; 0.44 ± 0.2 contralesion]. Type II neurons (responding to contralateral yaw rotation) after UCP have reduced gain (0.40 ± 0.27 normal, 0.35 ± 0.25 ipsilesion; 0.25 ± 0.18 contralesion). The difference between responses after UCP and after UL is primarily the distribution of type I and type II neurons in the vestibular nuclei (type I neurons comprise 66% in vestibular nuclei normally; 51% ipsilesion UCP; 59% contralesion UCP; 38% ipsilesion UL; 65% contralesion UL) and the magnitude of the responses of type II neurons ipsilateral to the lesion. These differences suggest that the need to compensate for unilateral loss of resting vestibular nerve activity after UL necessitates a different strategy for recovery of dynamic vestibular responses compared to after UCP.
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Affiliation(s)
- Shawn D Newlands
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, New York
| | - Min Wei
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, New York
| | - David Morgan
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, New York
| | - Hongge Luan
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, New York
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Gnanasegaram JJ, Parkes WJ, Cushing SL, McKnight CL, Papsin BC, Gordon KA. Stimulation from Cochlear Implant Electrodes Assists with Recovery from Asymmetric Perceptual Tilt: Evidence from the Subjective Visual Vertical Test. Front Integr Neurosci 2016; 10:32. [PMID: 27679562 PMCID: PMC5020067 DOI: 10.3389/fnint.2016.00032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/30/2016] [Indexed: 11/13/2022] Open
Abstract
Vestibular end organ impairment is highly prevalent in children who have sensorineural hearing loss (SNHL) rehabilitated with cochlear implants (CIs). As a result, spatial perception is likely to be impacted in this population. Of particular interest is the perception of visual vertical because it reflects a perceptual tilt in the roll axis and is sensitive to an imbalance in otolith function. The objectives of the present study were thus to identify abnormalities in perception of the vertical plane in children with SNHL and determine whether such abnormalities could be resolved with stimulation from the CI. Participants included 53 children (15.2 ± 4.0 years of age) with SNHL and vestibular loss, confirmed with vestibular evoked myogenic potential (VEMP) testing. Testing protocol was validated in a sample of nine young adults with normal hearing (28.8 ± 7.7 years). Perception of visual vertical was assessed using the static Subjective Visual Vertical (SVV) test performed with and without stimulation in the participants with cochleovestibular loss. Trains of electrical pulses were delivered by an electrode in the left and/or right ear. Asymmetric spatial orientation deficits were found in nearly half of the participants with CIs (24/53 [45%]). The abnormal perception in this cohort was exacerbated by visual tilts in the direction of their deficit. Electric pulse trains delivered using the CI shifted this abnormal perception towards center (i.e., normal; p = 0.007). Importantly, this benefit was realized regardless of which ear was stimulated. These results suggest a role for CI stimulation beyond the auditory system, in particular, for improving vestibular/balance function.
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Affiliation(s)
- Joshua J Gnanasegaram
- Archie's Cochlear Implant Laboratory, Department of Otolaryngology, The Hospital for Sick ChildrenToronto, ON, Canada; The Institute of Medical Science, University of TorontoToronto, ON, Canada
| | - William J Parkes
- Archie's Cochlear Implant Laboratory, Department of Otolaryngology, The Hospital for Sick ChildrenToronto, ON, Canada; Department of Otolaryngology-Head and Neck Surgery, University of TorontoToronto, ON, Canada
| | - Sharon L Cushing
- Archie's Cochlear Implant Laboratory, Department of Otolaryngology, The Hospital for Sick ChildrenToronto, ON, Canada; Department of Otolaryngology-Head and Neck Surgery, University of TorontoToronto, ON, Canada
| | - Carmen L McKnight
- Archie's Cochlear Implant Laboratory, Department of Otolaryngology, The Hospital for Sick Children Toronto, ON, Canada
| | - Blake C Papsin
- Archie's Cochlear Implant Laboratory, Department of Otolaryngology, The Hospital for Sick ChildrenToronto, ON, Canada; The Institute of Medical Science, University of TorontoToronto, ON, Canada; Department of Otolaryngology-Head and Neck Surgery, University of TorontoToronto, ON, Canada
| | - Karen A Gordon
- Archie's Cochlear Implant Laboratory, Department of Otolaryngology, The Hospital for Sick ChildrenToronto, ON, Canada; The Institute of Medical Science, University of TorontoToronto, ON, Canada
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DiGiovanna J, Nguyen TAK, Guinand N, Pérez-Fornos A, Micera S. Neural Network Model of Vestibular Nuclei Reaction to Onset of Vestibular Prosthetic Stimulation. Front Bioeng Biotechnol 2016; 4:34. [PMID: 27148528 PMCID: PMC4837148 DOI: 10.3389/fbioe.2016.00034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/30/2016] [Indexed: 11/24/2022] Open
Abstract
The vestibular system incorporates multiple sensory pathways to provide crucial information about head and body motion. Damage to the semicircular canals, the peripheral vestibular organs that sense rotational velocities of the head, can severely degrade the ability to perform activities of daily life. Vestibular prosthetics address this problem by using stimulating electrodes that can trigger primary vestibular afferents to modulate their firing rates, thus encoding head movement. These prostheses have been demonstrated chronically in multiple animal models and acutely tested in short-duration trials within the clinic in humans. However, mainly, due to limited opportunities to fully characterize stimulation parameters, there is a lack of understanding of “optimal” stimulation configurations for humans. Here, we model possible adaptive plasticity in the vestibular pathway. Specifically, this model highlights the influence of adaptation of synaptic strengths and offsets in the vestibular nuclei to compensate for the initial activation of the prosthetic. By changing the synaptic strengths, the model is able to replicate the clinical observation that erroneous eye movements are attenuated within 30 minutes without any change to the prosthetic stimulation rate. Although our model was only built to match this time point, we further examined how it affected subsequent pulse rate modulation (PRM) and pulse amplitude modulation (PAM). PAM was more effective than PRM for nearly all stimulation configurations during these acute tests. Two non-intuitive relationships highlighted by our model explain this performance discrepancy. Specifically, the attenuation of synaptic strengths for afferents stimulated during baseline adaptation and the discontinuity between baseline and residual firing rates both disproportionally boost PAM. Comodulation of pulse rate and amplitude has been experimentally shown to induce both excitatory and inhibitory eye movements even at high baseline stimulation rates. We also modeled comodulation and found synergistic combinations of stimulation parameters to achieve equivalent output to only amplitude modulation. This may be an important strategy to reduce current spread and misalignment. The model outputs reflected observed trends in clinical testing and aspects of existing vestibular prosthetic literature. Importantly, the model provided insight to efficiently explore the stimulation parameter space, which was helpful, given limited available patient time.
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Affiliation(s)
- Jack DiGiovanna
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
| | - T A K Nguyen
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
| | - Nils Guinand
- Cochlear Implant Center for French Speaking Switzerland, Service of Otorhinolaryngology - Head and Neck Surgery, Geneva University Hospitals , Geneva , Switzerland
| | - Angelica Pérez-Fornos
- Cochlear Implant Center for French Speaking Switzerland, Service of Otorhinolaryngology - Head and Neck Surgery, Geneva University Hospitals , Geneva , Switzerland
| | - Silvestro Micera
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
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Straka H, Zwergal A, Cullen KE. Vestibular animal models: contributions to understanding physiology and disease. J Neurol 2016; 263 Suppl 1:S10-23. [PMID: 27083880 PMCID: PMC4833800 DOI: 10.1007/s00415-015-7909-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/11/2015] [Accepted: 09/12/2015] [Indexed: 12/20/2022]
Abstract
Our knowledge of the vestibular sensory system, its functional significance for gaze and posture stabilization, and its capability to ensure accurate spatial orientation perception and spatial navigation has greatly benefitted from experimental approaches using a variety of vertebrate species. This review summarizes the attempts to establish the roles of semicircular canal and otolith endorgans in these functions followed by an overview of the most relevant fields of vestibular research including major findings that have advanced our understanding of how this system exerts its influence on reflexive and cognitive challenges encountered during daily life. In particular, we highlight the contributions of different animal models and the advantage of using a comparative research approach. Cross-species comparisons have established that the morpho-physiological properties underlying vestibular signal processing are evolutionarily inherent, thereby disclosing general principles. Based on the documented success of this approach, we suggest that future research employing a balanced spectrum of standard animal models such as fish/frog, mouse and primate will optimize our progress in understanding vestibular processing in health and disease. Moreover, we propose that this should be further supplemented by research employing more “exotic” species that offer unique experimental access and/or have specific vestibular adaptations due to unusual locomotor capabilities or lifestyles. Taken together this strategy will expedite our understanding of the basic principles underlying vestibular computations to reveal relevant translational aspects. Accordingly, studies employing animal models are indispensible and even mandatory for the development of new treatments, medication and technical aids (implants) for patients with vestibular pathologies.
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Affiliation(s)
- Hans Straka
- Department Biology II, Ludwig-Maximilians-University Munich, Grosshaderner Str. 2, 82152, Planegg, Germany. .,German Center for Vertigo and Balance Disorders, DSGZ, Ludwig-Maximilians-University of Munich, Munich, Germany.
| | - Andreas Zwergal
- German Center for Vertigo and Balance Disorders, DSGZ, Ludwig-Maximilians-University of Munich, Munich, Germany.,Department of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Kathleen E Cullen
- Department of Physiology, McGill University, Montreal, QC, H3A 0G4, Canada
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Lacour M, Helmchen C, Vidal PP. Vestibular compensation: the neuro-otologist's best friend. J Neurol 2016; 263 Suppl 1:S54-64. [PMID: 27083885 PMCID: PMC4833803 DOI: 10.1007/s00415-015-7903-4] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 02/05/2023]
Abstract
Why vestibular compensation (VC) after an acute unilateral vestibular loss is the neuro-otologist’s best friend is the question at the heart of this paper. The different plasticity mechanisms underlying VC are first reviewed, and the authors present thereafter the dual concept of vestibulo-centric versus distributed learning processes to explain the compensation of deficits resulting from the static versus dynamic vestibular imbalance. The main challenges for the plastic events occurring in the vestibular nuclei (VN) during a post-lesion critical period are neural protection, structural reorganization and rebalance of VN activity on both sides. Data from animal models show that modulation of the ipsilesional VN activity by the contralateral drive substitutes for the normal push–pull mechanism. On the other hand, sensory and behavioural substitutions are the main mechanisms implicated in the recovery of the dynamic functions. These newly elaborated sensorimotor reorganizations are vicarious idiosyncratic strategies implicating the VN and multisensory brain regions. Imaging studies in unilateral vestibular loss patients show the implication of a large neuronal network (VN, commissural pathways, vestibulo-cerebellum, thalamus, temporoparietal cortex, hippocampus, somatosensory and visual cortical areas). Changes in gray matter volume in these multisensory brain regions are structural changes supporting the sensory substitution mechanisms of VC. Finally, the authors summarize the two ways to improve VC in humans (neuropharmacology and vestibular rehabilitation therapy), and they conclude that VC would follow a “top-down” strategy in patients with acute vestibular lesions. Future challenges to understand VC are proposed.
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Affiliation(s)
- Michel Lacour
- Université Aix-Marseille/CNRS, UMR 7260, Fédération de Recherche 3C, Centre de St Charles, 3 Place Victor Hugo, 13331, Marseille Cedex 03, France. .,, 21 Impasse des Vertus, 13710, Fuveau, France.
| | - Christoph Helmchen
- Department of Neurology, University Hospitals Schleswig-Holstein, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Pierre-Paul Vidal
- Université Paris Descartes/CNRS, UMR-MD-SSA, COGNAC-G (COGNition and Action Group), 45 Rue des Saints Pères, 75270, Paris Cedex 06, France
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Modulation of central nystagmus by vision, proprioception, and efference copy signals: a systematic evaluation. J Neurol 2016; 263:735-42. [DOI: 10.1007/s00415-016-8032-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 01/11/2016] [Accepted: 01/12/2016] [Indexed: 10/22/2022]
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Abstract
The relative simplicity of the neural circuits that mediate vestibular reflexes is well suited for linking systems and cellular levels of analyses. Notably, a distinctive feature of the vestibular system is that neurons at the first central stage of sensory processing in the vestibular nuclei are premotor neurons; the same neurons that receive vestibular-nerve input also send direct projections to motor pathways. For example, the simplicity of the three-neuron pathway that mediates the vestibulo-ocular reflex leads to the generation of compensatory eye movements within ~5ms of a head movement. Similarly, relatively direct pathways between the labyrinth and spinal cord control vestibulospinal reflexes. A second distinctive feature of the vestibular system is that the first stage of central processing is strongly multimodal. This is because the vestibular nuclei receive inputs from a wide range of cortical, cerebellar, and other brainstem structures in addition to direct inputs from the vestibular nerve. Recent studies in alert animals have established how extravestibular signals shape these "simple" reflexes to meet the needs of current behavioral goal. Moreover, multimodal interactions at higher levels, such as the vestibular cerebellum, thalamus, and cortex, play a vital role in ensuring accurate self-motion and spatial orientation perception.
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Affiliation(s)
- K E Cullen
- Department of Physiology, McGill University, Montreal, Quebec, Canada.
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Mulavara AP, Kofman IS, De Dios YE, Miller C, Peters BT, Goel R, Galvan-Garza R, Bloomberg JJ. Using low levels of stochastic vestibular stimulation to improve locomotor stability. Front Syst Neurosci 2015; 9:117. [PMID: 26347619 PMCID: PMC4547107 DOI: 10.3389/fnsys.2015.00117] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 07/30/2015] [Indexed: 01/06/2023] Open
Abstract
Low levels of bipolar binaural white noise based imperceptible stochastic electrical stimulation to the vestibular system (stochastic vestibular stimulation, SVS) have been shown to improve stability during balance tasks in normal, healthy subjects by facilitating enhanced information transfer using stochastic resonance (SR) principles. We hypothesize that detection of time-critical sub-threshold sensory signals using low levels of bipolar binaural SVS based on SR principles will help improve stability of walking during support surface perturbations. In the current study 13 healthy subjects were exposed to short continuous support surface perturbations for 60 s while walking on a treadmill and simultaneously viewing perceptually matched linear optic flow. Low levels of bipolar binaural white noise based SVS were applied to the vestibular organs. Multiple trials of the treadmill locomotion test were performed with stimulation current levels varying in the range of 0–1500 μA, randomized across trials. The results show that subjects significantly improved their walking stability during support surface perturbations at stimulation levels with peak amplitude predominantly in the range of 100–500 μA consistent with the SR phenomenon. Additionally, objective perceptual motion thresholds were measured separately as estimates of internal noise while subjects sat on a chair with their eyes closed and received 1 Hz bipolar binaural sinusoidal electrical stimuli. The optimal improvement in walking stability was achieved on average with peak stimulation amplitudes of approximately 35% of perceptual motion threshold. This study shows the effectiveness of using low imperceptible levels of SVS to improve dynamic stability during walking on a laterally oscillating treadmill via the SR phenomenon.
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Affiliation(s)
| | - Igor S Kofman
- Wyle Science Technology and Engineering Group, Houston, TX USA
| | - Yiri E De Dios
- Wyle Science Technology and Engineering Group, Houston, TX USA
| | - Chris Miller
- Wyle Science Technology and Engineering Group, Houston, TX USA
| | - Brian T Peters
- Wyle Science Technology and Engineering Group, Houston, TX USA
| | | | | | - Jacob J Bloomberg
- Johnson Space Center, National Aeronautics and Space Administration, Houston, TX USA
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Carriot J, Jamali M, Cullen KE. Rapid adaptation of multisensory integration in vestibular pathways. Front Syst Neurosci 2015; 9:59. [PMID: 25932009 PMCID: PMC4399207 DOI: 10.3389/fnsys.2015.00059] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 03/29/2015] [Indexed: 12/02/2022] Open
Abstract
Sensing gravity is vital for our perception of spatial orientation, the control of upright posture, and generation of our everyday activities. When an astronaut transitions to microgravity or returns to earth, the vestibular input arising from self-motion will not match the brain's expectation. Our recent neurophysiological studies have provided insight into how the nervous system rapidly reorganizes when vestibular input becomes unreliable by both (1) updating its internal model of the sensory consequences of motion and (2) up-weighting more reliable extra-vestibular information. These neural strategies, in turn, are linked to improvements in sensorimotor performance (e.g., gaze and postural stability, locomotion, orienting) and perception characterized by similar time courses. We suggest that furthering our understanding of the neural mechanisms that underlie sensorimotor adaptation will have important implications for optimizing training programs for astronauts before and after space exploration missions and for the design of goal-oriented rehabilitation for patients.
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Affiliation(s)
- Jerome Carriot
- Department of Physiology, McGill University Montreal, QC, Canada
| | - Mohsen Jamali
- Department of Physiology, McGill University Montreal, QC, Canada
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Sequential [(18)F]FDG µPET whole-brain imaging of central vestibular compensation: a model of deafferentation-induced brain plasticity. Brain Struct Funct 2014; 221:159-70. [PMID: 25269833 DOI: 10.1007/s00429-014-0899-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 09/22/2014] [Indexed: 10/24/2022]
Abstract
Unilateral inner ear damage is followed by a rapid behavioural recovery due to central vestibular compensation. In this study, we utilized serial [(18)F]Fluoro-deoxyglucose ([(18)F]FDG)-µPET imaging in the rat to visualize changes in brain glucose metabolism during behavioural recovery after surgical and chemical unilateral labyrinthectomy, to determine the extent and time-course of the involvement of different brain regions in vestibular compensation and test previously described hypotheses of underlying mechanisms. Systematic patterns of relative changes of glucose metabolism (rCGM) were observed during vestibular compensation. A significant asymmetry of rCGM appeared in the vestibular nuclei, vestibulocerebellum, thalamus, multisensory vestibular cortex, hippocampus and amygdala in the acute phase of vestibular imbalance (4 h). This was followed by early vestibular compensation over 1-2 days where rCGM re-balanced between the vestibular nuclei, thalami and temporoparietal cortices and bilateral rCGM increase appeared in the hippocampus and amygdala. Subsequently over 2-7 days, rCGM increased in the ipsilesional spinal trigeminal nucleus and later (7-9 days) rCGM increased in the vestibulocerebellum bilaterally and the hypothalamus and persisted in the hippocampus. These systematic dynamic rCGM patterns during vestibular compensation, were confirmed in a second rat model of chemical unilateral labyrinthectomy by serial [(18)F]FDG-µPET. These findings show that deafferentation-induced plasticity after unilateral labyrinthectomy involves early mechanisms of re-balancing predominantly in the brainstem vestibular nuclei but also in thalamo-cortical and limbic areas, and indicate the contribution of spinocerebellar sensory inputs and vestibulocerebellar adaptation at the later stages of behavioural recovery.
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Newlands SD, Lin N, Wei M. Responses of non-eye movement central vestibular neurons to sinusoidal horizontal translation in compensated macaques after unilateral labyrinthectomy. J Neurophysiol 2014; 112:9-21. [PMID: 24717349 DOI: 10.1152/jn.00748.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
After vestibular labyrinth injury, behavioral deficits partially recover through the process of vestibular compensation. The present study was performed to improve our understanding of the physiology of the macaque vestibular system in the compensated state (>7 wk) after unilateral labyrinthectomy (UL). Three groups of vestibular nucleus neurons were included: pre-UL control neurons, neurons ipsilateral to the lesion, and neurons contralateral to the lesion. The firing responses of neurons sensitive to linear acceleration in the horizontal plane were recorded during sinusoidal horizontal translation directed along six different orientations (30° apart) at 0.5 Hz and 0.2 g peak acceleration (196 cm/s(2)). This data defined the vector of best response for each neuron in the horizontal plane, along which sensitivity, symmetry, detection threshold, and variability of firing were determined. Additionally, the responses of the same cells to translation over a series of frequencies (0.25-5.0 Hz) either in the interaural or naso-occipital orientation were obtained to define the frequency response characteristics in each group. We found a decrease in sensitivity, increase in threshold, and alteration in orientation of best responses in the vestibular nuclei after UL. Additionally, the phase relationship of the best neural response to translational stimulation changed with UL. The symmetry of individual neuron responses in the excitatory and inhibitory directions was unchanged by UL. Bilateral central utricular neurons still demonstrated two-dimension tuning after UL, consistent with spatio-temporal convergence from a single vestibular end-organ. These neuronal data correlate with known behavioral deficits after unilateral vestibular compromise.
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Affiliation(s)
- Shawn D Newlands
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas
| | - Nan Lin
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas
| | - Min Wei
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas
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Yu XJ, Thomassen JS, Dickman JD, Newlands SD, Angelaki DE. Long-term deficits in motion detection thresholds and spike count variability after unilateral vestibular lesion. J Neurophysiol 2014; 112:870-89. [PMID: 24848470 DOI: 10.1152/jn.00280.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The vestibular system operates in a push-pull fashion using signals from both labyrinths and an intricate bilateral organization. Unilateral vestibular lesions cause well-characterized motor deficits that are partially compensated over time and whose neural correlates have been traced in the mean response modulation of vestibular nuclei cells. Here we compare both response gains and neural detection thresholds of vestibular nuclei and semicircular canal afferent neurons in intact vs. unilateral-lesioned macaques using three-dimensional rotation and translation stimuli. We found increased stimulus-driven spike count variability and detection thresholds in semicircular canal afferents, although mean responses were unchanged, after contralateral labyrinth lesion. Analysis of trial-by-trial spike count correlations of a limited number of simultaneously recorded pairs of canal afferents suggests increased noise correlations after lesion. In addition, we also found persistent, chronic deficits in rotation detection thresholds of vestibular nuclei neurons, which were larger in the ipsilesional than the contralesional brain stem. These deficits, which persisted several months after lesion, were due to lower rotational response gains, whereas spike count variability was similar in intact and lesioned animals. In contrast to persistent deficits in rotation threshold, translation detection thresholds were not different from those in intact animals. These findings suggest that, after compensation, a single labyrinth is sufficient to recover motion sensitivity and normal thresholds for the otolith, but not the semicircular canal, system.
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Affiliation(s)
- Xiong-Jie Yu
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas; Department of Anatomy & Neurobiology, Washington University, St. Louis, Missouri; and
| | - Jakob S Thomassen
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas; Department of Anatomy & Neurobiology, Washington University, St. Louis, Missouri; and
| | - J David Dickman
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas; Department of Anatomy & Neurobiology, Washington University, St. Louis, Missouri; and
| | - Shawn D Newlands
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, New York
| | - Dora E Angelaki
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas; Department of Anatomy & Neurobiology, Washington University, St. Louis, Missouri; and
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Cullen KE. The neural encoding of self-generated and externally applied movement: implications for the perception of self-motion and spatial memory. Front Integr Neurosci 2014; 7:108. [PMID: 24454282 PMCID: PMC3888934 DOI: 10.3389/fnint.2013.00108] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/23/2013] [Indexed: 12/03/2022] Open
Abstract
The vestibular system is vital for maintaining an accurate representation of self-motion. As one moves (or is moved) toward a new place in the environment, signals from the vestibular sensors are relayed to higher-order centers. It is generally assumed the vestibular system provides a veridical representation of head motion to these centers for the perception of self-motion and spatial memory. In support of this idea, evidence from lesion studies suggests that vestibular inputs are required for the directional tuning of head direction cells in the limbic system as well as neurons in areas of multimodal association cortex. However, recent investigations in monkeys and mice challenge the notion that early vestibular pathways encode an absolute representation of head motion. Instead, processing at the first central stage is inherently multimodal. This minireview highlights recent progress that has been made towards understanding how the brain processes and interprets self-motion signals encoded by the vestibular otoliths and semicircular canals during everyday life. The following interrelated questions are considered. What information is available to the higher-order centers that contribute to self-motion perception? How do we distinguish between our own self-generated movements and those of the external world? And lastly, what are the implications of differences in the processing of these active vs. passive movements for spatial memory?
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Affiliation(s)
- Kathleen E Cullen
- Aerospace Medical Research Unit, Department of Physiology, McGill University Montreal, QC, Canada
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