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Bohlen MO, Bui K, Stahl JS, May PJ, Warren S. Mouse Extraocular Muscles and the Musculotopic Organization of Their Innervation. Anat Rec (Hoboken) 2019; 302:1865-1885. [PMID: 30993879 DOI: 10.1002/ar.24141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/18/2018] [Accepted: 11/25/2018] [Indexed: 12/24/2022]
Abstract
The organization of extraocular muscles (EOMs) and their motor nuclei was investigated in the mouse due to the increased importance of this model for oculomotor research. Mice showed a standard EOM organization pattern, although their eyes are set at the side of the head. They do have more prominent oblique muscles, whose insertion points differ from those of frontal-eyed species. Retrograde tracers revealed that the motoneuron layout aligns with the general vertebrate plan with respect to nuclei and laterality. The mouse departed in some significant respects from previously studied species. First, more overlap between the distributions of muscle-specific motoneuronal pools was present in the oculomotor nucleus (III). Furthermore, motoneuron dendrites for each pool filled the entire III and extended beyond the edge of the abducens nucleus (VI). This suggests mouse extraocular motoneuron afferents must target specific pools based on features other than dendritic distribution and nuclear borders. Second, abducens internuclear neurons are located outside the VI. We concluded this because no unlabeled abducens internuclear neurons were observed following lateral rectus muscle injections and because retrograde tracer injections into the III labeled cells immediately ventral and ventrolateral to the VI, not within it. This may provide an anatomical substrate for differential input to motoneurons and internuclear neurons that allows rodents to move their eyes more independently. Finally, while soma size measurements suggested motoneuron subpopulations supplying multiply and singly innervated muscle fibers are present, markers for neurofilaments and perineuronal nets indicated overlap in the size distributions of the two populations. Anat Rec, 302:1865-1885, 2019. © 2019 American Association for Anatomy.
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Affiliation(s)
- Martin O Bohlen
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Kevin Bui
- Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| | - John S Stahl
- Neurology Service, Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio.,Department of Neurology, Case Western Reserve University, Cleveland, Ohio
| | - Paul J May
- Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi.,Department of Ophthalmology, University of Mississippi Medical Center, Jackson, Mississippi.,Department of Neurology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Susan Warren
- Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
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Shimizu N, Wood S, Kushiro K, Perachio A, Makishima T. The role of GABAB receptors in the vestibular oculomotor system in mice. Behav Brain Res 2016; 302:152-9. [PMID: 26778789 DOI: 10.1016/j.bbr.2016.01.017] [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: 06/18/2015] [Revised: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 11/28/2022]
Abstract
Systemic administration of a gamma-amino butyric acid type B (GABAB) receptor agonist, baclofen, affects various physiological and psychological processes. To date, the effects on oculomotor system have been well characterized in primates, however those in mice have not been explored. In this study, we investigated the effects of baclofen focusing on vestibular-related eye movements. Two rotational paradigms, i.e. sinusoidal rotation and counter rotation were employed to stimulate semicircular canals and otolith organs in the inner ear. Experimental conditions (dosage, routes and onset of recording) were determined based on the prior studies exploring the behavioral effects of baclofen in mice. With an increase in dosage, both canal and otolith induced ocular responses were gradually affected. There was a clear distinction in the drug sensitivity showing that eye movements derived from direct vestibulo-ocular reflex pathways were relatively unaltered, while the responses through higher-order neural networks in the vestibular system were substantially decreased. These findings were consistent with those observed in primates suggesting a well-conserved role of GABAB receptors in the oculomotor system across frontal-eyed and lateral-eyed animals. We showed here a previously unrecognized effect of baclofen on the vestibular oculomotor function in mice. When interpreting general animal performance under the drug, the potential contribution of altered balance system should be taken into consideration.
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Affiliation(s)
- Naoki Shimizu
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA.
| | - Scott Wood
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA; Department of Psychology, Azusa Pacific University, Azusa California, USA
| | - Keisuke Kushiro
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Adrian Perachio
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Tomoko Makishima
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA.
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Tuma J, Kolinko Y, Vozeh F, Cendelin J. Mutation-related differences in exploratory, spatial, and depressive-like behavior in pcd and Lurcher cerebellar mutant mice. Front Behav Neurosci 2015; 9:116. [PMID: 26029065 PMCID: PMC4429248 DOI: 10.3389/fnbeh.2015.00116] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 04/21/2015] [Indexed: 01/16/2023] Open
Abstract
The cerebellum is not only essential for motor coordination but is also involved in cognitive and affective processes. These functions of the cerebellum and mechanisms of their disorders in cerebellar injury are not completely understood. There is a wide spectrum of cerebellar mutant mice which are used as models of hereditary cerebellar degenerations. Nevertheless, they differ in pathogenesis of manifestation of the particular mutation and also in the strain background. The aim of this work was to compare spatial navigation, learning, and memory in pcd and Lurcher mice, two of the most frequently used cerebellar mutants. The mice were tested in the open field for exploration behavior, in the Morris water maze with visible as well as reversal hidden platform tasks and in the forced swimming test for motivation assessment. Lurcher mice showed different space exploration activity in the open field and a lower tendency to depressive-like behavior in the forced swimming test compared with pcd mice. Severe deficit of spatial navigation was shown in both cerebellar mutants. However, the overall performance of Lurcher mice was better than that of pcd mutants. Lurcher mice showed the ability of visual guidance despite difficulties with the direct swim toward a goal. In the probe trial test, Lurcher mice preferred the visible platform rather than the more recent localization of the hidden goal.
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Affiliation(s)
- Jan Tuma
- Laboratory of Neurodegenerative Disorders, Faculty of Medicine in Pilsen, Biomedical Centre, Charles University in Prague Pilsen, Czech Republic ; Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
| | - Yaroslav Kolinko
- Laboratory of Neurodegenerative Disorders, Faculty of Medicine in Pilsen, Biomedical Centre, Charles University in Prague Pilsen, Czech Republic ; Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
| | - Frantisek Vozeh
- Laboratory of Neurodegenerative Disorders, Faculty of Medicine in Pilsen, Biomedical Centre, Charles University in Prague Pilsen, Czech Republic ; Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
| | - Jan Cendelin
- Laboratory of Neurodegenerative Disorders, Faculty of Medicine in Pilsen, Biomedical Centre, Charles University in Prague Pilsen, Czech Republic ; Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
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Shimizu N, Wood S, Kushiro K, Yanai S, Perachio A, Makishima T. Dynamic characteristics of otolith ocular response during counter rotation about dual yaw axes in mice. Neuroscience 2015; 285:204-14. [PMID: 25446357 DOI: 10.1016/j.neuroscience.2014.11.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/05/2014] [Accepted: 11/13/2014] [Indexed: 11/17/2022]
Abstract
The central vestibular system plays an important role in higher neural functions such as self-motion perception and spatial orientation. Its ability to store head angular velocity is called velocity storage mechanism (VSM), which has been thoroughly investigated across a wide range of species. However, little is known about the mouse VSM, because the mouse lacks typical ocular responses such as optokinetic after nystagmus or a dominant time constant of vestibulo-ocular reflex for which the VSM is critical. Experiments were conducted to examine the otolith-driven eye movements related to the VSM and verify its characteristics in mice. We used a novel approach to generate a similar rotating vector as a traditional off-vertical axis rotation (OVAR) but with a larger resultant gravito-inertial force (>1g) by using counter rotation centrifugation. Similar to results previously described in other animals during OVAR, two components of eye movements were induced, i.e. a sinusoidal modulatory eye movement (modulation component) on which a unidirectional nystagmus (bias component) was superimposed. Each response is considered to derive from different mechanisms; modulations arise predominantly through linear vestibulo-ocular reflex, whereas for the bias, the VSM is responsible. Data indicate that the mouse also has a well-developed vestibular system through otoliths inputs, showing its highly conserved nature across mammalian species. On the other hand, to reach a plateau state of bias, a higher frequency rotation or a larger gravito-inertial force was considered to be necessary than other larger animals. Compared with modulation, the bias had a more variable profile, suggesting an inherent complexity of higher-order neural processes in the brain. Our data provide the basis for further study of the central vestibular system in mice, however, the underlying individual variability should be taken into consideration.
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Affiliation(s)
- N Shimizu
- Department of Otolaryngology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, USA.
| | - S Wood
- Department of Otolaryngology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, USA; Department of Psychology, Azusa Pacific University, Azusa, CA, USA
| | - K Kushiro
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - S Yanai
- Aging Neuroscience Research Team, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - A Perachio
- Department of Otolaryngology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, USA
| | - T Makishima
- Department of Otolaryngology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, USA.
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Blödow A, Blödow J, Bloching MB, Helbig R, Walther LE. Horizontal VOR function shows frequency dynamics in vestibular schwannoma. Eur Arch Otorhinolaryngol 2014; 272:2143-8. [PMID: 24789061 DOI: 10.1007/s00405-014-3042-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/30/2014] [Indexed: 12/20/2022]
Abstract
The objective of this retrospective study was to investigate the horizontal vestibulo-ocular reflex (hVOR) pathway with caloric test (low-frequency hVOR) and video head impulse test (vHIT) (high-frequency hVOR) in patients with sporadic vestibular schwannoma (69 patients, 27-86 years, mean age 58.1 years) and to compare both test methods in terms of their sensitivity and specificity to detect a retrocochlear lesion. Test results with a unilateral weakness (UWCaloric) >25 % (caloric test) or a Mean-GainvHIT <0.79/asymmetry ratio of Gain (AR-GainvHIT) >8.5 % and accompanied refixation saccades (vHIT) were considered abnormal. The overall sensitivity of the caloric test was 72 %. The evaluation of AR-GainvHIT detected more abnormal cases than did Mean-GainvHIT (44 vs. 36 %). In up to 4 %, a normal caloric test result was related to an abnormal vHIT. There was only a moderate correlation of UWCaloric and AR-GainvHIT (r = 0.54, p < 0.05) with a linear regression line intercept/slope of 32.2/0.9 (p < 0.05). Receiver operating characteristics curve analysis exhibited at a UWCaloric of 50 % a vHIT sensitivity/specificity/positive predictive value/negative predictive value of 0.45/0.9/0.94/0.42. Vestibular testing at varying frequencies provides deeper insights into hVOR function and is helpful in detecting a cerebello-pontine lesion. Whereas caloric test yields a high sensitivity for nerve dysfunction, vHIT test reveals a remaining function of hVOR in the high-frequency range.
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Affiliation(s)
- Alexander Blödow
- Department of Otorhinolaryngology, Head and Neck Surgery and Communication Disorders, HELIOS-Clinic Berlin-Buch, Schwanebecker Chaussee 50, 13125, Berlin, Germany,
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Choi JY, Kim JS, Jung JM, Kwon DY, Park MH, Kim C, Choi J. Reversed Corrective Saccades during Head Impulse Test in Acute Cerebellar Dysfunction. THE CEREBELLUM 2013; 13:243-7. [DOI: 10.1007/s12311-013-0535-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Beraneck M, McKee JL, Aleisa M, Cullen KE. Asymmetric recovery in cerebellar-deficient mice following unilateral labyrinthectomy. J Neurophysiol 2008; 100:945-58. [PMID: 18509072 DOI: 10.1152/jn.90319.2008] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The term "vestibular compensation" refers to the resolution of motor deficits resulting from a peripheral vestibular lesion. We investigated the role of the cerebellum in the compensation process by characterizing the vestibuloocular reflex (VOR) evoked by head rotations at frequencies and velocities similar to those in natural behaviors in wild-type (WT) versus cerebellar-deficient Lurcher (Lc/+) mice. We found that during exploratory activity, normal mice produce head rotations largely consisting of frequencies < or =4 Hz and velocities and accelerations as large as 400 degrees/s and 5,000 degrees/s2, respectively. Accordingly, the VOR was characterized using sinusoidal rotations (0.2-4 Hz) as well as transient impulses (approximately 400 degrees/s; approximately 2,000 degrees/s2). Before lesions, WT and Lc/+ mice produced similar VOR responses to sinusoidal rotation. Lc/+ mice, however, had significantly reduced gains for transient stimuli. After unilateral labyrinthectomy, VOR recovery followed a similar course for WT and Lc/+ groups during the first week: gain was reduced by 80% for ipsilesionally directed head rotations on day 1 and improved for both strains to values of approximately 0.4 by day 5. Moreover, responses evoked by contralesionally directed rotations returned to prelesion in both strains within this period. However, unlike WT, which showed improving responses to ipsilesionally directed rotations, recovery plateaued after first week for Lc/+ mice. Our results show that despite nearly normal recovery in the acute phase, long-term compensation is compromised in Lc/+. We conclude that cerebellar pathways are critical for long-term restoration of VOR during head rotation toward the lesioned side, while noncerebellar pathways are sufficient to restore proper gaze stabilization during contralesionally directed movements.
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Affiliation(s)
- M Beraneck
- Department of Physiology, McGill University, Montreal, Quebec, Canada.
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Rotational responses of vestibular-nerve afferents innervating the semicircular canals in the C57BL/6 mouse. J Assoc Res Otolaryngol 2008; 9:334-48. [PMID: 18473139 DOI: 10.1007/s10162-008-0120-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 03/28/2008] [Indexed: 01/07/2023] Open
Abstract
Extracellular recordings were made from vestibular-nerve afferents innervating the semicircular canals in anesthetized C57BL/6 mice ranging in age from 4-24 weeks. A normalized coefficient of variation was used to divide afferents into regular (CV*<0.1) and irregular (CV*>0.1) groups. There were three overall conclusions from this study. First, mouse afferents resemble those of other mammals in properties such as resting discharge rate and dependence of response dynamics on discharge regularity. Second, there are differences in mouse afferents relative to other mammals that are likely related to the smaller size of the semicircular canals. The rotational sensitivity of mouse afferents is approximately threefold lower than that reported for afferents in other mammals. One consequence of the lower sensitivity is that mouse afferents have a larger linear range for encoding head velocity. The long time constant of afferent discharge, which is a measure of low-frequency response dynamics, is shorter in mouse afferents than in other species. Third, juvenile mice (age 4-7 weeks) appear to lack a class of low-sensitivity, highly irregular afferents that are present in adult animals (age 10-24 weeks). By analogy to studies in the chinchilla, these irregular afferents with low sensitivities for lower rotational frequencies correspond to calyx-only afferents. These findings suggest that, although the calyx ending on to type I hair cells is morphologically complete in mice by the age of about 1 month, the physiological response properties in these juvenile animals are not equivalent to those in adults.
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Oommen BS, Stahl JS. Eye orientation during static tilts and its relationship to spontaneous head pitch in the laboratory mouse. Brain Res 2007; 1193:57-66. [PMID: 18178173 DOI: 10.1016/j.brainres.2007.11.053] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2007] [Revised: 11/20/2007] [Accepted: 11/20/2007] [Indexed: 10/22/2022]
Abstract
Both eye position and head orientation are influenced by the macular (otolith) organs, via the tilt maculo-ocular reflex (tiltMOR) and the vestibulo-collic reflexes, respectively. The mechanisms that control head position also influence the rest position of the eye because head orientation influences eye position through the tiltMOR. Despite the increasing popularity of mice for studies of vestibular and ocular motor functions, relatively little is known in this species about tiltMOR, spontaneous orientation of the head, and their interrelationship. We used 2D video oculography to determine in C57BL/6 mice the absolute horizontal and vertical positions of the eyes over body orientations spanning 360 degrees about the pitch and roll axes. We also determined head pitch during ambulation in the same animals. Eye elevation varied approximately sinusoidally as functions of pitch or roll angle. Over the central +/-30 degrees of pitch, sensitivity and gain in the light were 31.7 degrees/g and 0.53, respectively. The corresponding values for roll were 31.5 degrees/g and 0.52. Absolute positions adopted in light and darkness differed only slightly. During ambulation, mice carried the lambda-bregma plane at a downward pitch of 29 degrees , corresponding to a horizontal eye position of 64 degrees and a vertical eye position of 22 degrees . The vertical position is near the center of the range of eye movements produced by the pitch tiltMOR. The results indicate that the tiltMOR is robust in this species and favor standardizing pitch orientation across laboratories. The robust tiltMOR also has significant methodological implications for the practice of pupil-tracking video oculography in this species.
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Affiliation(s)
- Brian S Oommen
- Case Western Reserve University School of Medicine, Cleveland, OH 44106-5040, USA
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Beraneck M, Cullen KE. Activity of Vestibular Nuclei Neurons During Vestibular and Optokinetic Stimulation in the Alert Mouse. J Neurophysiol 2007; 98:1549-65. [PMID: 17625061 DOI: 10.1152/jn.00590.2007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As a result of the availability of genetic mutant strains and development of noninvasive eye movements recording techniques, the mouse stands as a very interesting model for bridging the gap among behavioral responses, neuronal response dynamics studied in vivo, and cellular mechanisms investigated in vitro. Here we characterized the responses of individual neurons in the mouse vestibular nuclei during vestibular (horizontal whole body rotations) and full field visual stimulation. The majority of neurons (∼2/3) were sensitive to vestibular stimulation but not to eye movements. During the vestibular-ocular reflex (VOR), these neurons discharged in a manner comparable to the “vestibular only” (VO) neurons that have been previously described in primates. The remaining neurons [eye-movement-sensitive (ES) neurons] encoded both head-velocity and eye-position information during the VOR. When vestibular and visual stimulation were applied so that there was sensory conflict, the behavioral gain of the VOR was reduced. In turn, the modulation of sensitivity of VO neurons remained unaffected, whereas that of ES neurons was reduced. ES neurons were also modulated in response to full field visual stimulation that evoked the optokinetic reflex (OKR). Mouse VO neurons, however, unlike their primate counterpart, were not modulated during OKR. Taken together, our results show that the integration of visual and vestibular information in the mouse vestibular nucleus is limited to a subpopulation of neurons which likely supports gaze stabilization for both VOR and OKR.
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Affiliation(s)
- M Beraneck
- Department of Physiology, McGill University, Montreal, Quebec, Canada.
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11
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Baker JF. Dynamics and directionality of the vestibulo-collic reflex (VCR) in mice. Exp Brain Res 2005; 167:108-13. [PMID: 16041514 DOI: 10.1007/s00221-005-0031-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2005] [Accepted: 06/06/2005] [Indexed: 11/30/2022]
Abstract
The vestibulo-collic reflex (VCR) stabilizes the head in space by excitation of neck muscles that oppose head rotation. Recently, the mouse vestibulo-ocular reflex (VOR) has been characterized so that genetic manipulations of the vestibular system can be examined. We have characterized the dynamics and directionality of the VCR in mice restrained at the neck so that studies of vestibular system genetics may include comparisons to normal VCR in addition to VOR. Head rotations were measured in darkness with a three-dimensional search coil system during whole body rotations. The VCR in four C57BL/6 mice was present in pitch, roll, and yaw directions with an overall average gain of 0.28. Phase was accurately compensatory to oppose head rotation across a wide range of frequencies from 0.02 Hz to 2.0 Hz. Compensatory head rotations were greatest in the direction opposing the applied stimulus and weak or absent in other directions. Constant velocity rotations about horizontal axes elicited head velocity modulation and bias similar to that observed in the VOR. We conclude that the VCR of mice is similar to that in other mammals.
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Affiliation(s)
- James F Baker
- Department of Physiology and Institute for Neuroscience Physiology/Medical, Ward 5-071, M211, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611-3008, USA.
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Sekerková G, Ilijic E, Mugnaini E, Baker JF. Otolith organ or semicircular canal stimulation induces c-fos expression in unipolar brush cells and granule cells of cat and squirrel monkey. Exp Brain Res 2005; 164:286-300. [PMID: 15940501 DOI: 10.1007/s00221-005-2252-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Accepted: 11/30/2004] [Indexed: 11/29/2022]
Abstract
Immediate early gene expression in the cerebellar vermis of cats and squirrel monkeys was stimulated by prolonged whole body rotations. Continuous, earth-horizontal axis rotations that excited only otoliths or high velocity vertical axis rotations that excited only semicircular canals resulted in c-fos immunoreactive nuclei concentrated in the granular layer of lobules X and ventral IX (the nodulus and ventral uvula), which represent the medial parts of the vestibulo-cerebellum. Large clusters of labeled nuclei consisting mainly of granule cells and calretinin-positive unipolar brush cells were present in the granular layer, whereas Purkinje cell nuclei were unlabeled, and labeled basket and stellate cell nuclei were scattered in the molecular layer. In other vermal lobules there was a significant but less dense label than in the nodulus and ventral uvula. Generally, the extent of c-fos labeling of molecular layer interneurons was in relation to nuclear labeling of granular layer neurons: labeling of both basket and stellate cells accompanied nuclear labeling of neurons throughout the depth of the granular layer, whereas only stellate cells were labeled when nuclear labeling was restricted to the superficial granular layer. Yaw horizontal or roll vertical rotations each stimulated c-fos expression in the cat medial vestibulo-cerebellum to approximately the same extent. Low-velocity rotations resulted in much less c-fos expression. Similar, albeit less intense, patterns of c-fos activation were observed in monkeys. Concentrated c-fos expression in the medial vestibulo-cerebellum after exposure to a strong head velocity signal that could originate from either otolith or canal excitation suggests that granule and unipolar brush cells participate in a neuronal network for estimating head velocity, irrespective of the signal source.
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Affiliation(s)
- Gabriella Sekerková
- Northwestern University Institute for Neuroscience, Searle 5-474, 320 E. Superior Street, Chicago, IL 60611, USA
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Faulstich BM, Onori KA, du Lac S. Comparison of plasticity and development of mouse optokinetic and vestibulo-ocular reflexes suggests differential gain control mechanisms. Vision Res 2005; 44:3419-27. [PMID: 15536010 DOI: 10.1016/j.visres.2004.09.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Revised: 08/23/2004] [Indexed: 01/20/2023]
Abstract
Image stability during self-motion is achieved via a combination of the optokinetic and vestibulo-ocular reflexes (OKR and VOR). To determine whether distinct neuronal mechanisms are used to calibrate eye movements driven by visual and vestibular signals, we examined the developmental maturation and adaptive plasticity of the OKR and VOR in mice. The combined performance of the OKR and VOR, measured with infrared video oculography, produces nearly perfect gaze stability both in adult mice and in juveniles (postnatal days 21-26). Analyses of the OKR and VOR in isolation, however, indicate that VOR gains in juveniles are lower than in adult mice, while OKR gains are higher, indicating that juveniles rely more strongly on vision to stabilize gaze than do adults. Adaptive plasticity in the mouse OKR and VOR could be induced by 30 min of visual-vestibular mismatch training. Examination of the effects of training on the OKR and VOR revealed differential mechanisms and persistence of adaptive plasticity. Increases in VOR gain induced by rotating mice in the opposite direction to the visual surround were short-lasting and were accompanied by long-lasting increases in OKR gain. In contrast, decreases in VOR gain induced by rotating mice in the same direction as the visual surround were persistent and were accompanied by long-lasting increases in OKR gain. Vestibular training had little effect on either the OKR or VOR, while visual training induced robust and long-lasting increases in the OKR but had no effect on the VOR. These data indicate that multiple mechanisms of plasticity operate over distinct time courses to optimize oculomotor performance in mice.
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Affiliation(s)
- Bernd Michael Faulstich
- Systems Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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14
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Stahl JS. Using eye movements to assess brain function in mice. Vision Res 2005; 44:3401-10. [PMID: 15536008 DOI: 10.1016/j.visres.2004.09.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Revised: 08/26/2004] [Indexed: 10/26/2022]
Abstract
Examining eye movements is an important part of the neurological evaluation of humans; the distribution of the neural circuits that control these movements is such that they are disrupted--often in highly characteristic fashions--by many disease processes. Technical advances have made it possible to measure accurately the eye movements of mice, so it is now possible to use the detective power of eye movement recording to characterize neurological dysfunction in genetically altered strains. Here we introduce analytical tools used in ocular motor research and demonstrate their ability to reveal disorders of the visual pathways, inner ear, and cerebellum.
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Affiliation(s)
- John S Stahl
- Department of Neurology, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106, USA.
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Killian JE, Baker JF. Electromyographic activity of dorsal neck muscles in squirrel monkeys during rotations in an upright or upside down posture. J Neurophysiol 2005; 93:2587-99. [PMID: 15647395 DOI: 10.1152/jn.01229.2004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electromyographic (EMG) activity was recorded from occipitoscapularis, semispinalis, and splenius neck muscles in five alert squirrel monkeys during 0.25-Hz rotations about horizontal axes oriented at 22.5 degrees intervals, including pitch, roll, and intermediate axes. The animals were oriented in either upright or upside down posture. In the upright posture, all monkeys exhibited compensatory EMG activity with maximal activation during rotations about axes between pitch in the pitch forward direction and contralaterally directed roll. Response timing varied across animals with EMG peaks ranging from near pitch forward head velocity to near pitch forward head position. When the head was upside down, response dynamics and directionality were altered to varying degrees in different monkeys. The greatest change in response to head inversion was seen in the monkey that had response phases closest to head position, the least in the animal with phases closest to head velocity. The monkey with EMG response peaks closest to position phase showed nearly 180 degrees inversion of responses when the head was upside down, suggesting that in this monkey a righting reflex mediated by utricular signals was activated in the upside down posture. The monkey with EMG response peaks closest to velocity phase may have lacked a righting response and exhibited only a canal-mediated compensatory vestibulocervical reflex in both upright and upside down postures. The results suggest that reflex contraction of neck muscles in response to passive head rotation includes an interplay of compensatory and righting responses that varies from animal to animal.
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Affiliation(s)
- J Eric Killian
- Department of Physiology, Northwestern University, M211, 303 E. Chicago Ave., Chicago, IL 60611, USA
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Harrod CG, Baker JF. The vestibulo ocular reflex (VOR) in otoconia deficient head tilt (het) mutant mice versus wild type C57BL/6 mice. Brain Res 2003; 972:75-83. [PMID: 12711080 DOI: 10.1016/s0006-8993(03)02505-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The horizontal and vertical vestibulo ocular reflex (VOR) of head tilted (het) mutant mice was compared to C57BL/6 controls. Eye movements were recorded in darkness using a temporarily attached search coil. Contributions of semicircular canal versus otolith organ signals were investigated by providing a canal only (vertical axis) or canal plus otolith organ (horizontal axis) stimulus. In controls, rotations that stimulated only the canals (upright yaw and on tail roll) produced accurate VOR timing during middle frequency rotations at 0.5 Hz (gain 0.27, phase error 6 degrees), and a phase advanced VOR during low frequency rotations at 0.05 Hz (0.05, 115 degrees). In het mutant mice, these rotations produced a highly attenuated VOR response and phase errors at both 0.5 Hz (0.11, 42 degrees) and 0.05 Hz (0.01, 36 degrees). In controls, rotations that stimulated both the otolith organs and semicircular canals (upright roll and on tail yaw) produced higher VOR gains overall than were elicited during vertical axis rotations, with phase accurate VOR at both 0.5 Hz (0.52, 4 degrees) and 0.05 Hz (0.34, 9 degrees). In het mutant mice, these rotations produced a highly attenuated VOR response and phase errors at both 0.5 Hz (0.14, 51 degrees) and 0.05 Hz (0.01, 43 degrees). During constant velocity rotations about an earth horizontal axis, eye velocity bias and modulation were virtually absent in het mutant mice, while robust in controls. Control mice produced compensatory ocular deviations in response to static head tilt, but responses in het mice were weak and inconsistent. These results show that het mice not only lack all aspects of otolith mediated VOR, but also are deficient in canal mediated VOR. Because semicircular canals are normal in het mice, we conclude that central neurons of the canal VOR are dependent on otolith organ signals for normal performance.
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Affiliation(s)
- Christopher G Harrod
- Northwestern University, Department of Physiology and Institute for Neuroscience, 303 East Chicago Avenue, M211, Chicago, IL 60611, USA
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Abstract
In adult Lurcher mice virtually all cerebellar Purkinje cells have degenerated as a direct consequence of mutant gene action, providing a natural model for studying the effect of cerebellar cortical lesions on the generation of compensatory eye movements. Lurcher mice possess both optokinetic (OKR) and vestibular (VOR) compensatory reflexes. However, clear differences were observed in control of the OKR consisting of a large reduction in gain and a moderate increase in phase lag. Minor differences were also observed in the VOR in that gain and phase lead of the reflex were both increased in Lurcher animals. Subjecting Lurcher animals to eight days of visuovestibular training tested the assumption that increased VOR gain reflected an adaptive mechanism within remaining brainstem oculomotor pathways to compensate for the reduced OKR. Contrary to control animals, Lurcher animals were unable to modify either VOR or OKR in the course of training and therefore confirmed that an intact cerebellum is indispensable for the implementation of adaptive modifications to the oculomotor system.
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Affiliation(s)
- A M Van Alphen
- Department of Neuroscience, Erasmus University Rotterdam, Dr. Molewaterplein 50, 3000 DR Rotterdam, The Netherlands
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