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Ambrad Giovannetti E, Rancz E. Behind mouse eyes: The function and control of eye movements in mice. Neurosci Biobehav Rev 2024; 161:105671. [PMID: 38604571 DOI: 10.1016/j.neubiorev.2024.105671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/12/2024] [Accepted: 04/08/2024] [Indexed: 04/13/2024]
Abstract
The mouse visual system has become the most popular model to study the cellular and circuit mechanisms of sensory processing. However, the importance of eye movements only started to be appreciated recently. Eye movements provide a basis for predictive sensing and deliver insights into various brain functions and dysfunctions. A plethora of knowledge on the central control of eye movements and their role in perception and behaviour arose from work on primates. However, an overview of various eye movements in mice and a comparison to primates is missing. Here, we review the eye movement types described to date in mice and compare them to those observed in primates. We discuss the central neuronal mechanisms for their generation and control. Furthermore, we review the mounting literature on eye movements in mice during head-fixed and freely moving behaviours. Finally, we highlight gaps in our understanding and suggest future directions for research.
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Affiliation(s)
| | - Ede Rancz
- INMED, INSERM, Aix-Marseille University, Marseille, France.
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2
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Baizer JS. Functional and Neuropathological Evidence for a Role of the Brainstem in Autism. Front Integr Neurosci 2021; 15:748977. [PMID: 34744648 PMCID: PMC8565487 DOI: 10.3389/fnint.2021.748977] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/21/2021] [Indexed: 12/27/2022] Open
Abstract
The brainstem includes many nuclei and fiber tracts that mediate a wide range of functions. Data from two parallel approaches to the study of autistic spectrum disorder (ASD) implicate many brainstem structures. The first approach is to identify the functions affected in ASD and then trace the neural systems mediating those functions. While not included as core symptoms, three areas of function are frequently impaired in ASD: (1) Motor control both of the limbs and body and the control of eye movements; (2) Sensory information processing in vestibular and auditory systems; (3) Control of affect. There are critical brainstem nuclei mediating each of those functions. There are many nuclei critical for eye movement control including the superior colliculus. Vestibular information is first processed in the four nuclei of the vestibular nuclear complex. Auditory information is relayed to the dorsal and ventral cochlear nuclei and subsequently processed in multiple other brainstem nuclei. Critical structures in affect regulation are the brainstem sources of serotonin and norepinephrine, the raphe nuclei and the locus ceruleus. The second approach is the analysis of abnormalities from direct study of ASD brains. The structure most commonly identified as abnormal in neuropathological studies is the cerebellum. It is classically a major component of the motor system, critical for coordination. It has also been implicated in cognitive and language functions, among the core symptoms of ASD. This structure works very closely with the cerebral cortex; the cortex and the cerebellum show parallel enlargement over evolution. The cerebellum receives input from cortex via relays in the pontine nuclei. In addition, climbing fiber input to cerebellum comes from the inferior olive of the medulla. Mossy fiber input comes from the arcuate nucleus of the medulla as well as the pontine nuclei. The cerebellum projects to several brainstem nuclei including the vestibular nuclear complex and the red nucleus. There are thus multiple brainstem nuclei distributed at all levels of the brainstem, medulla, pons, and midbrain, that participate in functions affected in ASD. There is direct evidence that the cerebellum may be abnormal in ASD. The evidence strongly indicates that analysis of these structures could add to our understanding of the neural basis of ASD.
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Affiliation(s)
- Joan S. Baizer
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
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3
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温 超, 陈 太, 邓 巧, 刘 强, 王 巍, 徐 开, 阮 宏, 林 鹏. [Study on normal reference range of smooth tracking gain for healthy young people]. LIN CHUANG ER BI YAN HOU TOU JING WAI KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY, HEAD, AND NECK SURGERY 2020; 34:733-736. [PMID: 32842208 PMCID: PMC10127913 DOI: 10.13201/j.issn.2096-7993.2020.08.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Indexed: 06/11/2023]
Abstract
Objective:Analysis of normal reference value of smooth pursuit test for normal young people. Method:Thirty normal young volunteers were tested by Synapsys videonystagmography. The maximum horizontal tracking angle was 30 °, the vertical maximum tracking angle was 20°, and the frequency was 0.30 Hz, 0.45 Hz and 0.60 Hz, respectively, and the gain under different conditions is used as the observation index. Result:When the frequency is 0.3 Hz, 0.45 Hz, 0.60 Hz, the left and right horizontal gain is 0.92±0.07/0.93±0.07, 0.87±0.08/0.88±0.11, 0.79±0.11/0.78±0.13, respectively, and the asymmetry of left/right gain is 0.021±0.017, 0.031±0.026, 0.037±0.040; the up and down vertical gain is 0.82±0.16/0.80±0.16, 0.78±0.17/0.72±0.15, 0.68±0.20/0.61±0.15, and the asymmetry of the upper/lower gain is 0.046±0.045, 0.069±0.058, 0.109±0.076. Comparing and analyzing the paired left and right gain values of the three frequencies by paired t test, the differences were not statistically significant (P>0.05). Paired t -test of gain value for different frequency of up and down stationary tracking, the difference was not statistically significant at 0.30 Hz(P>0.05), but the gain at 0.45 Hz and 0.60 Hz has significant difference(P<0.05). Comparing the gains of different frequencies in the same direction, the differences in analysis of variance were statistically significant(P<0.05). Conclusion:The gain value of smooth pursuit test for normal young people can be affected by tracking frequency and direction. At the same frequency, the left/right tracking of 3 frequencies and the up/down tracking gain values of 0.30 Hz are symmetrical, but at 0.45 Hz and 0.6 Hz, the up tracking gain is greater than the down tracking gain, and the gain value in the same direction gradually decreases with the increase of frequency, is the clinical smooth pursuit test is mainly based on 0.30 Hz.
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Affiliation(s)
- 超 温
- 天津医科大学一中心临床学院(天津, 300192)The First Center Clinical College of Tianjin Medical University, Tianjin, 300192, China
| | - 太生 陈
- 天津市第一中心医院耳鼻咽喉头颈外科 天津市耳鼻喉科研究所 天津市临床重点学科(耳鼻咽喉科学) 天津市听觉言 语与平衡医学重点实验室 天津市耳鼻喉科质量控制中心Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Institute of Otorhinolaryngology of Tianjin, Key Clinical Discipline (Otorhinolaryngology) of Tianjin, Key Laboratory of Auditory, Verbal and Balance Medicine of Tianjin, Center of Otorhinolaryngology Clinical Quality Control of Tianjin
| | - 巧媚 邓
- 天津市第一中心医院耳鼻咽喉头颈外科 天津市耳鼻喉科研究所 天津市临床重点学科(耳鼻咽喉科学) 天津市听觉言 语与平衡医学重点实验室 天津市耳鼻喉科质量控制中心Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Institute of Otorhinolaryngology of Tianjin, Key Clinical Discipline (Otorhinolaryngology) of Tianjin, Key Laboratory of Auditory, Verbal and Balance Medicine of Tianjin, Center of Otorhinolaryngology Clinical Quality Control of Tianjin
| | - 强 刘
- 天津市第一中心医院耳鼻咽喉头颈外科 天津市耳鼻喉科研究所 天津市临床重点学科(耳鼻咽喉科学) 天津市听觉言 语与平衡医学重点实验室 天津市耳鼻喉科质量控制中心Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Institute of Otorhinolaryngology of Tianjin, Key Clinical Discipline (Otorhinolaryngology) of Tianjin, Key Laboratory of Auditory, Verbal and Balance Medicine of Tianjin, Center of Otorhinolaryngology Clinical Quality Control of Tianjin
| | - 巍 王
- 天津市第一中心医院耳鼻咽喉头颈外科 天津市耳鼻喉科研究所 天津市临床重点学科(耳鼻咽喉科学) 天津市听觉言 语与平衡医学重点实验室 天津市耳鼻喉科质量控制中心Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Institute of Otorhinolaryngology of Tianjin, Key Clinical Discipline (Otorhinolaryngology) of Tianjin, Key Laboratory of Auditory, Verbal and Balance Medicine of Tianjin, Center of Otorhinolaryngology Clinical Quality Control of Tianjin
| | - 开旭 徐
- 天津市第一中心医院耳鼻咽喉头颈外科 天津市耳鼻喉科研究所 天津市临床重点学科(耳鼻咽喉科学) 天津市听觉言 语与平衡医学重点实验室 天津市耳鼻喉科质量控制中心Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Institute of Otorhinolaryngology of Tianjin, Key Clinical Discipline (Otorhinolaryngology) of Tianjin, Key Laboratory of Auditory, Verbal and Balance Medicine of Tianjin, Center of Otorhinolaryngology Clinical Quality Control of Tianjin
| | - 宏莹 阮
- 天津市第一中心医院耳鼻咽喉头颈外科 天津市耳鼻喉科研究所 天津市临床重点学科(耳鼻咽喉科学) 天津市听觉言 语与平衡医学重点实验室 天津市耳鼻喉科质量控制中心Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Institute of Otorhinolaryngology of Tianjin, Key Clinical Discipline (Otorhinolaryngology) of Tianjin, Key Laboratory of Auditory, Verbal and Balance Medicine of Tianjin, Center of Otorhinolaryngology Clinical Quality Control of Tianjin
| | - 鹏 林
- 天津市第一中心医院耳鼻咽喉头颈外科 天津市耳鼻喉科研究所 天津市临床重点学科(耳鼻咽喉科学) 天津市听觉言 语与平衡医学重点实验室 天津市耳鼻喉科质量控制中心Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Institute of Otorhinolaryngology of Tianjin, Key Clinical Discipline (Otorhinolaryngology) of Tianjin, Key Laboratory of Auditory, Verbal and Balance Medicine of Tianjin, Center of Otorhinolaryngology Clinical Quality Control of Tianjin
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Pallus A, Walton MMG. Abnormal Tuning in Nucleus Prepositus Hypoglossi of Monkeys With "A" Pattern Exotropia. Invest Ophthalmol Vis Sci 2020; 61:45. [PMID: 32446250 PMCID: PMC7405765 DOI: 10.1167/iovs.61.5.45] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose In many individuals with pattern strabismus, the vertical misalignment varies with horizontal eye position. It has been proposed that these cross-axis effects result from abnormal cross-talk between brainstem structures that would normally encode horizontal and vertical eye position and velocity. The nucleus prepositus hypoglossi (NPH) is an ideal structure to test this overarching hypothesis. Neurons in the NPH are believed to mathematically integrate eye velocity signals to generate a tonic signal related to horizontal eye position. We hypothesized that, in monkeys with A-pattern exotropia and vertical inconcomitance, these neurons would show an abnormally large sensitivity to vertical eye position. Methods Three rhesus monkeys (1 normal and 2 with A-pattern exotropia) were trained to maintain fixation on a visual target as it stepped to various locations on a tangent screen. Extracellular neural activity was recorded from neurons in the NPH. Each neuron's sensitivity to horizontal and vertical eye position was estimated using multiple linear regression and preferred directions computed for each eye. Results Unexpectedly, the mean preferred directions for the left eye were normal in the monkeys with A-pattern exotropia. For the right eye, there was a clear upward deviation for the right NPH and a downward deviation for the left NPH. In addition, the R2 values were significantly lower for model fits for neurons recorded from the exotropic monkeys. Conclusions We suggest that vertical inconcomitance results from inappropriate vertical-to-horizontal cross-talk that affects the two eyes differently.
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5
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Abstract
BACKGROUND The brainstem contains numerous structures including afferent and efferent fibers that are involved in generation and control of eye movements. EVIDENCE ACQUISITION These structures give rise to distinct patterns of abnormal eye movements when damaged. Defining these ocular motor abnormalities allows a topographic diagnosis of a lesion within the brainstem. RESULTS Although diverse patterns of impaired eye movements may be observed in lesions of the brainstem, medullary lesions primarily cause various patterns of nystagmus and impaired vestibular eye movements without obvious ophthalmoplegia. By contrast, pontine ophthalmoplegia is characterized by abnormal eye movements in the horizontal plane, while midbrain lesions typically show vertical ophthalmoplegia in addition to pupillary and eyelid abnormalities. CONCLUSIONS Recognition of the patterns and characteristics of abnormal eye movements observed in brainstem lesions is important in understanding the roles of each neural structure and circuit in ocular motor control as well as in localizing the offending lesion.
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6
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Albert ST, Hadjiosif AM, Jang J, Zimnik AJ, Soteropoulos DS, Baker SN, Churchland MM, Krakauer JW, Shadmehr R. Postural control of arm and fingers through integration of movement commands. eLife 2020; 9:e52507. [PMID: 32043973 PMCID: PMC7062460 DOI: 10.7554/elife.52507] [Citation(s) in RCA: 20] [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: 10/06/2019] [Accepted: 02/03/2020] [Indexed: 12/29/2022] Open
Abstract
Every movement ends in a period of stillness. Current models assume that commands that hold the limb at a target location do not depend on the commands that moved the limb to that location. Here, we report a surprising relationship between movement and posture in primates: on a within-trial basis, the commands that hold the arm and finger at a target location depend on the mathematical integration of the commands that moved the limb to that location. Following damage to the corticospinal tract, both the move and hold period commands become more variable. However, the hold period commands retain their dependence on the integral of the move period commands. Thus, our data suggest that the postural controller possesses a feedforward module that uses move commands to calculate a component of hold commands. This computation may arise within an unknown subcortical system that integrates cortical commands to stabilize limb posture.
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Affiliation(s)
- Scott T Albert
- Department of Biomedical Engineering, Johns Hopkins School of MedicineBaltimoreUnited States
| | - Alkis M Hadjiosif
- Department of Neurology, Johns Hopkins School of MedicineBaltimoreUnited States
| | - Jihoon Jang
- Department of Biomedical Engineering, Johns Hopkins School of MedicineBaltimoreUnited States
| | - Andrew J Zimnik
- Department of Neuroscience, Columbia UniversityNew YorkUnited States
| | | | - Stuart N Baker
- Institute of Neuroscience, Newcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Mark M Churchland
- Department of Neuroscience, Columbia UniversityNew YorkUnited States
| | - John W Krakauer
- Department of Neurology, Johns Hopkins School of MedicineBaltimoreUnited States
| | - Reza Shadmehr
- Department of Biomedical Engineering, Johns Hopkins School of MedicineBaltimoreUnited States
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7
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Walton MMG, Mustari MJ. Comparison of three models of saccade disconjugacy in strabismus. J Neurophysiol 2017; 118:3175-3193. [PMID: 28904108 DOI: 10.1152/jn.00983.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 12/12/2022] Open
Abstract
In pattern strabismus the horizontal and vertical misalignments vary with eye position along the orthogonal axis. The disorder is typically described in terms of overaction or underaction of oblique muscles. Recent behavioral studies in humans and monkeys, however, have reported that such actions are insufficient to fully explain the patterns of directional and amplitude disconjugacy of saccades. There is mounting evidence that the oculomotor abnormalities associated with strabismus are at least partially attributable to neurophysiological abnormalities. A number of control systems models have been developed to simulate the kinematic characteristics of saccades in normal primates. In the present study we sought to determine whether these models could simulate the abnormalities of saccades in strabismus by making two assumptions: 1) in strabismus the burst generator gains differ for the two eyes and 2) abnormal crosstalk exists between the horizontal and vertical saccadic circuits in the brain stem. We tested three models, distinguished by the location of the horizontal-vertical crosstalk. All three models were able to simulate amplitude and directional saccade disconjugacy, postsaccadic drift, and a pattern strabismus for static fixation, but they made different predictions about the dynamics of saccades. By assuming that crosstalk occurs at multiple nodes, the Distributed Crosstalk Model correctly predicted the dynamics of saccades. These new models make additional predictions that can be tested with future neurophysiological experiments.NEW & NOTEWORTHY Over the past several decades, numerous control systems models have been devised to simulate the known kinematic features of saccades in normal primates. These models have proven valuable to neurophysiology, as a means of generating testable predictions. The present manuscript, as far as we are aware, is the first to present control systems models to simulate the known abnormalities of saccades in strabismus.
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Affiliation(s)
- Mark M G Walton
- Washington National Primate Research Center, University of Washington, Seattle, Washington;
| | - Michael J Mustari
- Washington National Primate Research Center, University of Washington, Seattle, Washington.,Department of Ophthalmology, University of Washington, Seattle, Washington; and.,Department of Biological Structure, University of Washington, Seattle, Washington
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8
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Vishwanathan A, Daie K, Ramirez AD, Lichtman JW, Aksay ERF, Seung HS. Electron Microscopic Reconstruction of Functionally Identified Cells in a Neural Integrator. Curr Biol 2017; 27:2137-2147.e3. [PMID: 28712570 PMCID: PMC5569574 DOI: 10.1016/j.cub.2017.06.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/02/2017] [Accepted: 06/09/2017] [Indexed: 11/27/2022]
Abstract
Neural integrators are involved in a variety of sensorimotor and cognitive behaviors. The oculomotor system contains a simple example, a hindbrain neural circuit that takes velocity signals as inputs and temporally integrates them to control eye position. Here we investigated the structural underpinnings of temporal integration in the larval zebrafish by first identifying integrator neurons using two-photon calcium imaging and then reconstructing the same neurons through serial electron microscopic analysis. Integrator neurons were identified as those neurons with activities highly correlated with eye position during spontaneous eye movements. Three morphological classes of neurons were observed: ipsilaterally projecting neurons located medially, contralaterally projecting neurons located more laterally, and a population at the extreme lateral edge of the hindbrain for which we were not able to identify axons. Based on their somatic locations, we inferred that neurons with only ipsilaterally projecting axons are glutamatergic, whereas neurons with only contralaterally projecting axons are largely GABAergic. Dendritic and synaptic organization of the ipsilaterally projecting neurons suggests a broad sampling from inputs on the ipsilateral side. We also observed the first conclusive evidence of synapses between integrator neurons, which have long been hypothesized by recurrent network models of integration via positive feedback.
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Affiliation(s)
| | - Kayvon Daie
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10021, USA
| | - Alexandro D Ramirez
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10021, USA
| | - Jeff W Lichtman
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Emre R F Aksay
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10021, USA
| | - H Sebastian Seung
- Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Computer Science Department, Princeton University, Princeton, NJ 08544, USA.
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Butler WN, Smith KS, van der Meer MAA, Taube JS. The Head-Direction Signal Plays a Functional Role as a Neural Compass during Navigation. Curr Biol 2017; 27:1259-1267. [PMID: 28416119 DOI: 10.1016/j.cub.2017.03.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/24/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
Abstract
The rat limbic system contains head direction (HD) cells that fire according to heading in the horizontal plane, and these cells are thought to provide animals with an internal compass. Previous work has found that HD cell tuning correlates with behavior on navigational tasks, but a direct, causal link between HD cells and navigation has not been demonstrated. Here, we show that pathway-specific optogenetic inhibition of the nucleus prepositus caused HD cells to become directionally unstable under dark conditions without affecting the animals' locomotion. Then, using the same technique, we found that this decoupling of the HD signal in the absence of visual cues caused the animals to make directional homing errors and that the magnitude and direction of these errors were in a range that corresponded to the degree of instability observed in the HD signal. These results provide evidence that the HD signal plays a causal role as a neural compass in navigation.
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Affiliation(s)
- William N Butler
- Department of Psychological and Brain Sciences, Dartmouth College, 6207 Moore Hall, Hanover, NH 03755, USA
| | - Kyle S Smith
- Department of Psychological and Brain Sciences, Dartmouth College, 6207 Moore Hall, Hanover, NH 03755, USA
| | - Matthijs A A van der Meer
- Department of Psychological and Brain Sciences, Dartmouth College, 6207 Moore Hall, Hanover, NH 03755, USA
| | - Jeffrey S Taube
- Department of Psychological and Brain Sciences, Dartmouth College, 6207 Moore Hall, Hanover, NH 03755, USA.
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Walton MMG, Pallus A, Fleuriet J, Mustari MJ, Tarczy-Hornoch K. Neural mechanisms of oculomotor abnormalities in the infantile strabismus syndrome. J Neurophysiol 2017; 118:280-299. [PMID: 28404829 DOI: 10.1152/jn.00934.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/03/2017] [Accepted: 04/07/2017] [Indexed: 02/08/2023] Open
Abstract
Infantile strabismus is characterized by numerous visual and oculomotor abnormalities. Recently nonhuman primate models of infantile strabismus have been established, with characteristics that closely match those observed in human patients. This has made it possible to study the neural basis for visual and oculomotor symptoms in infantile strabismus. In this review, we consider the available evidence for neural abnormalities in structures related to oculomotor pathways ranging from visual cortex to oculomotor nuclei. These studies provide compelling evidence that a disturbance of binocular vision during a sensitive period early in life, whatever the cause, results in a cascade of abnormalities through numerous brain areas involved in visual functions and eye movements.
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Affiliation(s)
- Mark M G Walton
- Washington National Primate Research Center, University of Washington, Seattle, Washington;
| | - Adam Pallus
- Washington National Primate Research Center, University of Washington, Seattle, Washington.,Department of Ophthalmology, University of Washington, Seattle, Washington
| | - Jérome Fleuriet
- Washington National Primate Research Center, University of Washington, Seattle, Washington.,Department of Ophthalmology, University of Washington, Seattle, Washington
| | - Michael J Mustari
- Washington National Primate Research Center, University of Washington, Seattle, Washington.,Department of Ophthalmology, University of Washington, Seattle, Washington.,Department of Biological Structure, University of Washington, Seattle, Washington; and
| | - Kristina Tarczy-Hornoch
- Department of Ophthalmology, University of Washington, Seattle, Washington.,Seattle Children's Hospital, Seattle, Washington
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11
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Kim SH, Zee DS, du Lac S, Kim HJ, Kim JS. Nucleus prepositus hypoglossi lesions produce a unique ocular motor syndrome. Neurology 2016; 87:2026-2033. [PMID: 27733568 DOI: 10.1212/wnl.0000000000003316] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/27/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To describe the ocular motor abnormalities in 9 patients with a lesion involving the nucleus prepositus hypoglossi (NPH), a key constituent of a vestibular-cerebellar-brainstem neural network that ensures that the eyes are held steady in all positions of gaze. METHODS We recorded eye movements, including the vestibulo-ocular reflex during head impulses, in patients with vertigo and a lesion involving the NPH. RESULTS Our patients showed an ipsilesional-beating spontaneous nystagmus, horizontal gaze-evoked nystagmus more intense on looking toward the ipsilesional side, impaired pursuit more to the ipsilesional side, central patterns of head-shaking nystagmus, contralateral eye deviation, and decreased vestibulo-ocular reflex gain during contralesionally directed head impulses. CONCLUSIONS We attribute these findings to an imbalance in the NPH-inferior olive-flocculus-vestibular nucleus loop, and the ocular motor abnormalities provide a new brainstem localization for patients with acute vertigo.
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Affiliation(s)
- Sung-Hee Kim
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - David S Zee
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - Sascha du Lac
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - Hyo Jung Kim
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea
| | - Ji-Soo Kim
- From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea.
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12
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Lee SU, Park SH, Park JJ, Kim HJ, Han MK, Bae HJ, Kim JS. Dorsal Medullary Infarction. Stroke 2015; 46:3081-7. [DOI: 10.1161/strokeaha.115.010972] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 09/09/2015] [Indexed: 12/24/2022]
Affiliation(s)
- Sun-Uk Lee
- From the Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, Korea (S.-U.L.); Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea (S.-H.P., M.-K.H., H.-J.B., J.-S.K.); Department of Radiology, Samsung Medical Center, Seoul, South Korea (J.-J.P.); and Department of Biomedical Laboratory Science, Kyungdong University, Goseong-Gun, Gangwon-do, Korea (H.J.K.)
| | - Seong-Ho Park
- From the Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, Korea (S.-U.L.); Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea (S.-H.P., M.-K.H., H.-J.B., J.-S.K.); Department of Radiology, Samsung Medical Center, Seoul, South Korea (J.-J.P.); and Department of Biomedical Laboratory Science, Kyungdong University, Goseong-Gun, Gangwon-do, Korea (H.J.K.)
| | - Jeong-Jin Park
- From the Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, Korea (S.-U.L.); Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea (S.-H.P., M.-K.H., H.-J.B., J.-S.K.); Department of Radiology, Samsung Medical Center, Seoul, South Korea (J.-J.P.); and Department of Biomedical Laboratory Science, Kyungdong University, Goseong-Gun, Gangwon-do, Korea (H.J.K.)
| | - Hyo Jung Kim
- From the Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, Korea (S.-U.L.); Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea (S.-H.P., M.-K.H., H.-J.B., J.-S.K.); Department of Radiology, Samsung Medical Center, Seoul, South Korea (J.-J.P.); and Department of Biomedical Laboratory Science, Kyungdong University, Goseong-Gun, Gangwon-do, Korea (H.J.K.)
| | - Moon-Ku Han
- From the Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, Korea (S.-U.L.); Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea (S.-H.P., M.-K.H., H.-J.B., J.-S.K.); Department of Radiology, Samsung Medical Center, Seoul, South Korea (J.-J.P.); and Department of Biomedical Laboratory Science, Kyungdong University, Goseong-Gun, Gangwon-do, Korea (H.J.K.)
| | - Hee-Joon Bae
- From the Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, Korea (S.-U.L.); Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea (S.-H.P., M.-K.H., H.-J.B., J.-S.K.); Department of Radiology, Samsung Medical Center, Seoul, South Korea (J.-J.P.); and Department of Biomedical Laboratory Science, Kyungdong University, Goseong-Gun, Gangwon-do, Korea (H.J.K.)
| | - Ji-Soo Kim
- From the Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, Korea (S.-U.L.); Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea (S.-H.P., M.-K.H., H.-J.B., J.-S.K.); Department of Radiology, Samsung Medical Center, Seoul, South Korea (J.-J.P.); and Department of Biomedical Laboratory Science, Kyungdong University, Goseong-Gun, Gangwon-do, Korea (H.J.K.)
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13
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Daie K, Goldman MS, Aksay ERF. Spatial patterns of persistent neural activity vary with the behavioral context of short-term memory. Neuron 2015; 85:847-60. [PMID: 25661184 DOI: 10.1016/j.neuron.2015.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 08/25/2014] [Accepted: 01/06/2015] [Indexed: 10/24/2022]
Abstract
A short-term memory can be evoked by different inputs and control separate targets in different behavioral contexts. To address the circuit mechanisms underlying context-dependent memory function, we determined through optical imaging how memory is encoded at the whole-network level in two behavioral settings. Persistent neural activity maintaining a memory of desired eye position was imaged throughout the oculomotor integrator after saccadic or optokinetic stimulation. While eye position was encoded by the amplitude of network activity, the spatial patterns of firing were context dependent: cells located caudally generally were most persistent following saccadic input, whereas cells located rostrally were most persistent following optokinetic input. To explain these data, we computationally identified four independent modes of network activity and found these were differentially accessed by saccadic and optokinetic inputs. These results show how a circuit can simultaneously encode memory value and behavioral context, respectively, in its amplitude and spatial pattern of persistent firing.
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Affiliation(s)
- Kayvon Daie
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10065, USA; Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - Mark S Goldman
- Center for Neuroscience, Department of Neurobiology, Physiology, and Behavior, and Department of Ophthalmology and Vision Science, University of California, Davis, Davis, CA 95618, USA.
| | - Emre R F Aksay
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10065, USA.
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14
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Baizer JS. Unique features of the human brainstem and cerebellum. Front Hum Neurosci 2014; 8:202. [PMID: 24778611 PMCID: PMC3985031 DOI: 10.3389/fnhum.2014.00202] [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: 01/26/2014] [Accepted: 03/21/2014] [Indexed: 12/28/2022] Open
Abstract
The cerebral cortex is greatly expanded in the human brain. There is a parallel expansion of the cerebellum, which is interconnected with the cerebral cortex. We have asked if there are accompanying changes in the organization of pre-cerebellar brainstem structures. We have examined the cytoarchitectonic and neurochemical organization of the human medulla and pons. We studied human cases from the Witelson Normal Brain Collection, analyzing Nissl sections and sections processed for immunohistochemistry for multiple markers including the calcium-binding proteins calbindin, calretinin, and parvalbumin, non-phosphorylated neurofilament protein, and the synthetic enzyme for nitric oxide, nitric oxide synthase. We have also compared the neurochemical organization of the human brainstem to that of several other species including the chimpanzee, macaque and squirrel monkey, cat, and rodent, again using Nissl staining and immunohistochemistry. We found that there are major differences in the human brainstem, ranging from relatively subtle differences in the neurochemical organization of structures found in each of the species studied to the emergence of altogether new structures in the human brainstem. Two aspects of human cortical organization, individual differences and left–right asymmetry, are also seen in the brainstem (principal nucleus of the inferior olive) and the cerebellum (the dentate nucleus). We suggest that uniquely human motor and cognitive abilities derive from changes at all levels of the central nervous system, including the cerebellum and brainstem, and not just the cerebral cortex.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, University at Buffalo , Buffalo, NY , USA
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15
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Dale A, Cullen KE. The nucleus prepositus predominantly outputs eye movement-related information during passive and active self-motion. J Neurophysiol 2013; 109:1900-11. [PMID: 23324318 DOI: 10.1152/jn.00788.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Maintaining a constant representation of our heading as we move through the world requires the accurate estimate of spatial orientation. As one turns (or is turned) toward a new heading, signals from the semicircular canals are relayed through the vestibular system to higher-order centers that encode head direction. To date, there is no direct electrophysiological evidence confirming the first relay point of head-motion signals from the vestibular nuclei, but previous anatomical and lesion studies have identified the nucleus prepositus as a likely candidate. Whereas burst-tonic neurons encode only eye-movement signals during head-fixed eye motion and passive vestibular stimulation, these neurons have not been studied during self-generated movements. Here, we specifically address whether burst-tonic neurons encode head motion during active behaviors. Single-unit responses were recorded from the nucleus prepositus of rhesus monkeys and compared for head-restrained and active conditions with comparable eye velocities. We found that neurons consistently encoded eye position and velocity across conditions but did not exhibit significant sensitivity to head position or velocity. Additionally, response sensitivities varied as a function of eye velocity, similar to abducens motoneurons and consistent with their role in gaze control and stabilization. Thus our results demonstrate that the primate nucleus prepositus chiefly encodes eye movement even during active head-movement behaviors, a finding inconsistent with the proposal that this nucleus makes a direct contribution to head-direction cell tuning. Given its ascending projections, however, we speculate that this eye-movement information is integrated with other inputs in establishing higher-order spatial representations.
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Affiliation(s)
- Alexis Dale
- Department of Physiology, McGill University, Montreal, Quebec, Canada
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16
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Baizer JS, Paolone NA, Sherwood CC, Hof PR. Neurochemical organization of the vestibular brainstem in the common chimpanzee (Pan troglodytes). Brain Struct Funct 2012. [PMID: 23179862 DOI: 10.1007/s00429-012-0470-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chimpanzees are one of the closest living relatives of humans. However, the cognitive and motor abilities of chimpanzees and humans are quite different. The fact that humans are habitually bipedal and chimpanzees are not implies different uses of vestibular information in the control of posture and balance. Furthermore, bipedal locomotion permits the development of fine motor skills of the hand and tool use in humans, suggesting differences between species in the structures and circuitry for manual control. Much motor behavior is mediated via cerebro-cerebellar circuits that depend on brainstem relays. In this study, we investigated the organization of the vestibular brainstem in chimpanzees to gain insight into whether these structures differ in their anatomy from humans. We identified the four nuclei of vestibular nuclear complex in the chimpanzee and also looked at several other precerebellar structures. The size and arrangement of some of these nuclei differed between chimpanzees and humans, and also displayed considerable inter-individual variation. We identified regions within the cytoarchitectonically defined medial vestibular nucleus visualized by immunoreactivity to the calcium-binding proteins calretinin and calbindin as previously shown in other species including human. We have found that the nucleus paramedianus dorsalis, which is identified in the human but not in macaque monkeys, is present in the chimpanzee brainstem. However, the arcuate nucleus, which is present in humans, was not found in chimpanzees. The present study reveals major differences in the organization of the vestibular brainstem among Old World anthropoid primate species. Furthermore, in chimpanzees, as well as humans, there is individual variability in the organization of brainstem nuclei.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, NY, 14214, USA,
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17
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Baizer JS, Paolone NA, Witelson SF. Nonphosphorylated neurofilament protein is expressed by scattered neurons in the human vestibular brainstem. Brain Res 2011; 1382:45-56. [DOI: 10.1016/j.brainres.2011.01.079] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/21/2011] [Accepted: 01/22/2011] [Indexed: 12/25/2022]
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18
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Abstract
We review current concepts of nystagmus and saccadic oscillations, applying a pathophysiological approach. We begin by discussing how nystagmus may arise when the mechanisms that normally hold gaze steady are impaired. We then describe the clinical and laboratory evaluation of patients with ocular oscillations. Next, we systematically review the features of nystagmus arising from peripheral and central vestibular disorders, nystagmus due to an abnormal gaze-holding mechanism (neural integrator), and nystagmus occurring when vision is compromised. We then discuss forms of nystagmus for which the pathogenesis is not well understood, including acquired pendular nystagmus and congenital forms of nystagmus. We then summarize the spectrum of saccadic disorders that disrupt steady gaze, from intrusions to flutter and opsoclonus. Finally, we review current treatment options for nystagmus and saccadic oscillations, including drugs, surgery, and optical methods. Examples of each type of nystagmus are provided in the form of figures.
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Affiliation(s)
- Matthew J Thurtell
- Departments of Neurology and Daroff-Dell'Osso Laboratory, Veterans Affairs Medical Center and University Hospitals, Case Western Reserve University, Cleveland, OH 44106, USA
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19
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Lai CH, Yiu CN, Lai SK, Ng KP, Yung KK, Shum DK, Chan YS. Maturation of canal-related brainstem neurons in the detection of horizontal angular acceleration in rats. J Comp Neurol 2010; 518:1742-63. [DOI: 10.1002/cne.22300] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Green AM, Angelaki DE. Internal models and neural computation in the vestibular system. Exp Brain Res 2010; 200:197-222. [PMID: 19937232 PMCID: PMC2853943 DOI: 10.1007/s00221-009-2054-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 10/08/2009] [Indexed: 10/20/2022]
Abstract
The vestibular system is vital for motor control and spatial self-motion perception. Afferents from the otolith organs and the semicircular canals converge with optokinetic, somatosensory and motor-related signals in the vestibular nuclei, which are reciprocally interconnected with the vestibulocerebellar cortex and deep cerebellar nuclei. Here, we review the properties of the many cell types in the vestibular nuclei, as well as some fundamental computations implemented within this brainstem-cerebellar circuitry. These include the sensorimotor transformations for reflex generation, the neural computations for inertial motion estimation, the distinction between active and passive head movements, as well as the integration of vestibular and proprioceptive information for body motion estimation. A common theme in the solution to such computational problems is the concept of internal models and their neural implementation. Recent studies have shed new insights into important organizational principles that closely resemble those proposed for other sensorimotor systems, where their neural basis has often been more difficult to identify. As such, the vestibular system provides an excellent model to explore common neural processing strategies relevant both for reflexive and for goal-directed, voluntary movement as well as perception.
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Affiliation(s)
- Andrea M Green
- Dépt. de Physiologie, Université de Montréal, 2960 Chemin de la Tour, Rm. 4141, Montreal, QC H3T 1J4, Canada.
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21
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Weiss AH, Doherty D, Parisi M, Shaw D, Glass I, Phillips JO. Eye movement abnormalities in Joubert syndrome. Invest Ophthalmol Vis Sci 2009; 50:4669-77. [PMID: 19443711 DOI: 10.1167/iovs.08-3299] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Joubert syndrome is a genetic disorder characterized by hypoplasia of the midline cerebellum and deficiency of crossed connections between neural structures in the brain stem that control eye movements. The goal of the study was to quantify the eye movement abnormalities that occur in Joubert syndrome. METHODS Eye movements were recorded in response to stationary stimuli and stimuli designed to elicit smooth pursuit, saccades, optokinetic nystagmus (OKN), vestibulo-ocular reflex (VOR), and vergence using video-oculography or Skalar search coils in 8 patients with Joubert syndrome. All patients underwent high-resolution magnetic resonance imaging (MRI). RESULTS All patients had the highly characteristic molar tooth sign on brain MRI. Six patients had conjugate pendular (n = 4) or see-saw nystagmus (n = 2); gaze holding was stable in four patients. Smooth-pursuit gains were 0.28 to 1.19, 0.11 to 0.68, and 0.33 to 0.73 at peak stimulus velocities of 10, 20, and 30 deg/s in six patients; smooth pursuit could not be elicited in four patients. Saccade gains in five patients ranged from 0.35 to 0.91 and velocities ranged from 60.9 to 259.5 deg/s. Targeted saccades could not be elicited in five patients. Horizontal OKN gain was uniformly reduced across gratings drifted at velocities of 15, 30, and 45 deg/s. VOR gain was 0.8 or higher and phase appropriate in three of seven subjects; VOR gain was 0.3 or less and phase was indeterminate in four subjects. CONCLUSIONS The abnormalities in gaze-holding and eye movements are consistent with the distributed abnormalities of midline cerebellum and brain stem regions associated with Joubert syndrome.
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Affiliation(s)
- Avery H Weiss
- Division of Ophthalmology, Children's Hospital and Regional Medical Center, Seattle, Washington 98115, USA.
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22
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Hogie M, Guerbet M, Reber A. The toxic effects of toluene on the optokinetic nystagmus in pigmented rats. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2009; 72:872-878. [PMID: 18397809 DOI: 10.1016/j.ecoenv.2008.02.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 02/18/2008] [Accepted: 02/24/2008] [Indexed: 05/26/2023]
Abstract
The effects of 375 mgm(-3) (100 ppm) toluene in air inhalation were evaluated on pigmented rats during either repeated exposures over five consecutive days 3h a day or during a single 4-h exposure. At the end of the inhalation period, the animals were returned to fresh air to evaluate their ability to recover optokinetic performance. The optokinetic responses were analyzed using a magnetic search coil technique previously described. After repeated toluene exposure, the eye position at rest of all the rats was unsteady. In response to visual stimulation, the eye velocity was slower and more irregular than in the control state. At the end of the stimulation, the environment of the animals became stationary, but the eye did not immediately return to a fixed stable position. A similar effect was observed after a single exposure. An increase of the optokinetic deficit was observed after single or repeated 375 mgm(-3) toluene exposures. No recovery was observed even after a single exposure. In view of the fact that toluene is a widely used solvent, these results show that inhalation of low concentrations, even for short single exposures, must be taken into account, because gaze destabilization could cause vertigo symptoms.
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Affiliation(s)
- Manuela Hogie
- Faculty of Sciences, Laboratory of Neurosciences and Environment, Rouen University, 76821 Mont Saint Aignan Cedex, France
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23
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Abstract
Smooth pursuit impairment is recognized clinically by the presence of saccadic tracking of a small object and quantified by reduction in pursuit gain, the ratio of smooth eye movement velocity to the velocity of a foveal target. Correlation of the site of brain lesions, identified by imaging or neuropathological examination, with defective smooth pursuit determines brain structures that are necessary for smooth pursuit. Paretic, low gain, pursuit occurs toward the side of lesions at the junction of the parietal, occipital and temporal lobes (area V5), the frontal eye field and their subcortical projections, including the posterior limb of the internal capsule, the midbrain and the basal pontine nuclei. Paresis of ipsiversive pursuit also results from damage to the ventral paraflocculus and caudal vermis of the cerebellum. Paresis of contraversive pursuit is a feature of damage to the lateral medulla. Retinotopic pursuit paresis consists of low gain pursuit in the visual hemifield contralateral to damage to the optic radiation, striate cortex or area V5. Craniotopic paresis of smooth pursuit consists of impaired smooth eye movement generation contralateral to the orbital midposition after acute unilateral frontal or parietal lobe damage. Omnidirectional saccadic pursuit is a most sensitive sign of bilateral or diffuse cerebral, cerebellar or brainstem disease. The anatomical and physiological bases of defective smooth pursuit are discussed here in the context of the effects of lesion in the human brain.
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Affiliation(s)
- James A Sharpe
- Division of Neurology, University Health Network WW5-440 TWH, University of Toronto, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8.
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24
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Baizer JS, Baker JF, Haas K, Lima R. Neurochemical organization of the nucleus paramedianus dorsalis in the human. Brain Res 2007; 1176:45-52. [PMID: 17869228 PMCID: PMC2078602 DOI: 10.1016/j.brainres.2007.08.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 08/07/2007] [Accepted: 08/08/2007] [Indexed: 11/26/2022]
Abstract
We have characterized the neurochemical organization of a small brainstem nucleus in the human brain, the nucleus paramedianus dorsalis (PMD). PMD is located adjacent and medial to the nucleus prepositus hypoglossi (PH) in the dorsal medulla and is distinguished by the pattern of immunoreactivity of cells and fibers to several markers including calcium-binding proteins, a synthetic enzyme for nitric oxide (neuronal nitric oxide synthase, nNOS) and a nonphosphorylated neurofilament protein (antibody SMI-32). In transverse sections, PMD is oval with its long axis aligned with the dorsal border of the brainstem. We identified PMD in eight human brainstems, but found some variability both in its cross-sectional area and in its A-P extent among cases. It includes calretinin immunoreactive large cells with oval or polygonal cell bodies. Cells in PMD are not immunoreactive for either calbindin or parvalbumin, but a few fibers immunoreactive to each protein are found within its central region. Cells in PMD are also immunoreactive to nNOS, and immunoreactivity to a neurofilament protein shows many labeled cells and fibers. No similar region is identified in atlases of the cat, mouse, rat or monkey brain, nor does immunoreactivity to any of the markers that delineate it in the human reveal a comparable region in those species. The territory that PMD occupies is included in PH in other species. Since anatomical and physiological data in animals suggest that PH may have multiple subregions, we suggest that the PMD in human may be a further differentiation of PH and may have functions related to the vestibular control of eye movements.
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Affiliation(s)
- Joan S. Baizer
- Department of Physiology and Biophysics, 123 Sherman Hall, University at Buffalo, State University of New York, Buffalo New York, 14214, phone: 716-829-3096, FAX: 716-829-2344,
| | - James F. Baker
- Department of Physiology, Institute for Neuroscience, Physiology/Medical, Ward 5-071, M211, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, ILL 60611-3008
| | - Kristin Haas
- Department of Physiology and Biophysics, 123 Sherman Hall, University at Buffalo, State University of New York, Buffalo New York, 14214, phone: 716-829-3096, FAX: 716-829-2344,
| | - Raquel Lima
- Department of Physiology and Biophysics, 123 Sherman Hall, University at Buffalo, State University of New York, Buffalo New York, 14214, phone: 716-829-3096, FAX: 716-829-2344,
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25
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Kralj-Hans I, Baizer JS, Swales C, Glickstein M. Independent roles for the dorsal paraflocculus and vermal lobule VII of the cerebellum in visuomotor coordination. Exp Brain Res 2006; 177:209-22. [PMID: 16951960 DOI: 10.1007/s00221-006-0661-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Accepted: 07/31/2006] [Indexed: 11/30/2022]
Abstract
Two distinct areas of cerebellar cortex, vermal lobule VII and the dorsal paraflocculus (DPFl) receive visual input. To help understand the visuomotor functions of these two regions, we compared their afferent and efferent connections using the tracers wheatgerm agglutinin horseradish peroxidase (WGA-HRP) and biotinilated dextran amine (BDA). The sources of both mossy fibre and climbing fibre input to the two areas are different. The main mossy fibre input to lobule VII is from the nucleus reticularis tegmenti pontis (NRTP), which relays visual information from the superior colliculus, while the main mossy fibre input to the DPFl is from the pontine nuclei, relaying information from cortical visual areas. The DPFl and lobule VII both also receive mossy fibre input from several common brainstem regions, but from different subsets of cells. These include visual input from the dorsolateral pons, and vestibular-oculomotor input from the medial vestibular nucleus (MVe) and the nucleus prepositus hypoglossi (Nph). The climbing fibre input to the two cerebellar regions is from different subdivisions of the inferior olivary nuclei. Climbing fibres from the caudal medial accessory olive (cMAO) project to lobule VII, while the rostral MAO (rMAO) and the principal olive (PO) project to the DPFl. The efferent projections from lobule VII and the DPF1 are to all of the recognised oculomotor and visual areas within the deep cerebellar nuclei, but to separate territories. Both regions play a role in eye movement control. The DPFl may also have a role in visually guided reaching.
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Affiliation(s)
- Ines Kralj-Hans
- Department of Anatomy, University College London, Gower Street, London, WC1E 6BT, England
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26
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Baizer JS, Baker JF. Neurochemically defined cell columns in the nucleus prepositus hypoglossi of the cat and monkey. Brain Res 2006; 1094:127-37. [PMID: 16701575 DOI: 10.1016/j.brainres.2006.03.113] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 03/29/2006] [Accepted: 03/30/2006] [Indexed: 10/24/2022]
Abstract
Many studies have shown that the nucleus prepositus hypoglossi (PH) participates with the vestibular nuclear complex, the cerebellum and the oculomotor nuclei in the control of eye movements. We have looked at the neurochemical organization of PH in the cat and monkey using a recently developed antibody, 8B3, that recognizes a chondroitin sulfate proteoglycan. In the cat, immunoreactivity to 8B3 labels a set of cells in PH. On frontal sections, these cells form a cluster that is seen over the entire anterior-posterior (A-P) extent of PH, but the number of cells in the cluster changes with A-P level. Earlier studies have identified an A-P cell column in PH of the cat whose neurons synthesize nitric oxide. We have used both single- and double-label protocols to investigate the relation between the two cell groups. Single-label studies show spatial overlap but that the cells immunoreactive to nitric oxide synthase (nNOS) are more numerous than cells immunoreactive to 8B3. Double-label studies show that all cells immunoreactive to 8B3 were also immunoreactive to nNOS, but, as suggested by the single-label data, there are many nNOS-immunoreactive cells not immunoreactive to 8B3. Populations of 8B3 and nNOS-immunoreactive cells are also found in PH of squirrel and macaque monkeys. The results suggest that nNOS-immunoreactive cells in PH may consist of two functionally different populations.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, University at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214-3078, USA.
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Metts BA, Kaufman GD, Perachio AA. Polysynaptic inputs to vestibular efferent neurons as revealed by viral transneuronal tracing. Exp Brain Res 2006; 172:261-74. [PMID: 16421729 DOI: 10.1007/s00221-005-0328-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Accepted: 12/07/2005] [Indexed: 10/25/2022]
Abstract
The Bartha strain of the alpha-herpes pseudorabies virus (PrV) was used as a retrograde transneuronal tracer to map synaptic inputs to the vestibular efferent neurons of the Mongolian gerbil, Meriones unguiculatus. Although previous experiments have shown that vestibular efferent neurons respond to visual motion and somatosensory stimuli, the anatomic connections mediating those responses are unknown. PrV was injected unilaterally into the horizontal semicircular canal neuroepithelium of gerbils, where it was taken up by efferent axon terminals. The virus was then retrogradely transported to efferent cell bodies, replicated, and transported into synaptic endings projecting onto the efferent cells. Thirty animals were sacrificed at approximately 5-h increments between 75 and 105 h post-infection after determining that shorter time points had no central infection. Infected cells were visualized immunohistochemically. Temporal progression of neuronal infection was used to determine the nature of primary and higher order projections to the vestibular efferent neurons. Animals sacrificed at 80-94 h post-inoculation exhibited immunostaining in the dorsal and ventral group of vestibular efferent neurons, predominately on the contralateral side. Neurons within the medial, gigantocellular, and lateral reticular formations were among the first cells infected thereafter. At 95 h, additional virus-labeled cell groups included the solitary, area postrema, pontine reticular, prepositus, dorsal raphe, tegmental, the subcoeruleus nuclei, the nucleus of Darkschewitsch, and the inferior olivary beta and ventrolateral subnuclei. Analysis beyond 95 h revealed virus-infected neurons located in the vestibulo-cerebellar and motor cortices. Paraventricular, lateral, and posterior hypothalamic cells, as well as central amygdala cells, were also labeled. Spinal cord tissue exhibited no labeling in the intermediolateral cell column, but scattered cells were found in the central cervical nucleus. The results suggest functional associations among efferent feedback regulation of labyrinthine sensory input and both behavioral and autonomic systems, and support a closed-looped vestibular feedback model with additional open-loop polysynaptic inputs.
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Affiliation(s)
- Brent A Metts
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Büttner U, Büttner-Ennever JA. Present concepts of oculomotor organization. PROGRESS IN BRAIN RESEARCH 2006; 151:1-42. [PMID: 16221584 DOI: 10.1016/s0079-6123(05)51001-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This chapter gives an introduction to the oculomotor system, thus providing a framework for the subsequent chapters. This chapter describes the characteristics, and outlines the structures involved, of the five basic types of eye movements, for gaze holding ("neural integrator") and eye movements in three dimensions (Listing's law, pulleys).
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Affiliation(s)
- U Büttner
- Department of Neurology, Institute of Anatomy, Ludwig-Maximilians University, Marchioninistr. 15, D-81377 Munich, Germany.
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29
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Abstract
The cytoarchitecture and the histochemistry of nucleus prepositus hypoglossi and its afferent and efferent connections to oculomotor structures are described. The functional significance of the afferent connections of the nucleus is discussed in terms of current knowledge of the firing behavior of prepositus neurons in alert animals. The efferent connections of the nucleus and the results of lesion experiments suggest that it plays a role in a variety of functions related to the control of gaze.
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Affiliation(s)
- Robert A McCrea
- Department of Neurobiology, Pharmacology and Physiology, University of Chicago, 947 E. 58th St., Chicago, IL 60637, USA.
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Huk AC, Shadlen MN. Neural activity in macaque parietal cortex reflects temporal integration of visual motion signals during perceptual decision making. J Neurosci 2005; 25:10420-36. [PMID: 16280581 PMCID: PMC6725829 DOI: 10.1523/jneurosci.4684-04.2005] [Citation(s) in RCA: 371] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Revised: 09/18/2005] [Accepted: 09/20/2005] [Indexed: 11/21/2022] Open
Abstract
Decision-making often requires the accumulation and maintenance of evidence over time. Although the neural signals underlying sensory processing have been studied extensively, little is known about how the brain accrues and holds these sensory signals to guide later actions. Previous work has suggested that neural activity in the lateral intraparietal area (LIP) of the monkey brain reflects the formation of perceptual decisions in a random dot direction-discrimination task in which monkeys communicate their decisions with eye-movement responses. We tested the hypothesis that decision-related neural activity in LIP represents the time integral of the momentary motion "evidence." By briefly perturbing the strength of the visual motion stimulus during the formation of perceptual decisions, we tested whether this LIP activity reflected a persistent, integrated "memory" of these brief sensory events. We found that the responses of LIP neurons reflected substantial temporal integration. Brief pulses had persistent effects on both the monkeys' choices and the responses of neurons in LIP, lasting up to 800 ms after appearance. These results demonstrate that LIP is involved in neural time integration underlying the accumulation of evidence in this task. Additional analyses suggest that decision-related LIP responses, as well as behavioral choices and reaction times, can be explained by near-perfect time integration that stops when a criterion amount of evidence has been accumulated. Temporal integration may be a fundamental computation underlying higher cognitive functions that are dissociated from immediate sensory inputs or motor outputs.
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Affiliation(s)
- Alexander C Huk
- Center for Perceptual Systems, Department of Psychology, University of Texas, Austin, Texas 78712, USA.
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Abstract
The paramedian pontine reticular formation contains the premotoneuronal cell groups that constitute the saccadic burst generator and control saccadic eye movements. Despite years of study and numerous investigations, the rostral portion of this area has received comparatively little attention, particularly the cell type known as long-lead burst neurons (LLBNs). Several hypotheses about the functional role of LLBNs in saccade generation have been proposed, although there is little information with which to assess them. To address this issue, I mapped and recorded LLBNs in the rostral pons to measure their discharge characteristics and correlate those characteristics with the metrics of the concurrent saccades. On the basis of their discharge and location, I identified three types of LLBNs in the rostral pons: excitatory (eLLBN), dorsal (dLLBN), and nucleus reticularis tegmenti pontis (nrtp) LLBNs. The eLLBNs, encountered throughout the pons, discharge for ipsilateral saccades in proportion to saccade amplitude, velocity, and duration. The dLLBNs, found at the pontomesencephalic junction, discharge maximally for ipsilateral saccades of a particular amplitude, usually <10 degrees , and are not associated with a particular anatomical nucleus. The nrtp LLBNs, previously described as vector LLBNs, discharge for saccades of a particular direction and sometimes a particular amplitude. The discharge of the eLLBNs suggests they drive motor neurons. The anatomical projections of the nrtp LLBNs suggest that their involvement in saccade production is less direct. The discharge of dLLBNs is consistent with a role in providing the "trigger" signal that initiates saccades.
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Affiliation(s)
- Chris R S Kaneko
- Department of Physiology and Biophysics, Box 357290, and Washington National Primate Research Center, University of Washington, Seattle, WA 98195-7290, USA.
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32
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Baizer JS, Baker JF. Immunoreactivity for calcium-binding proteins defines subregions of the vestibular nuclear complex of the cat. Exp Brain Res 2005; 164:78-91. [PMID: 15662522 PMCID: PMC1201542 DOI: 10.1007/s00221-004-2211-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Accepted: 11/22/2004] [Indexed: 12/18/2022]
Abstract
The vestibular nuclear complex (VNC) is classically divided into four nuclei on the basis of cytoarchitectonics. However, anatomical data on the distribution of afferents to the VNC and the distribution of cells of origin of different efferent pathways suggest a more complex internal organization. Immunoreactivity for calcium-binding proteins has proven useful in many areas of the brain for revealing structure not visible with cell, fiber or Golgi stains. We have looked at the VNC of the cat using immunoreactivity for the calcium-binding proteins calbindin, calretinin and parvalbumin. Immunoreactivity for calretinin revealed a small, intensely stained region of cell bodies and processes just beneath the fourth ventricle in the medial vestibular nucleus. A presumably homologous region has been described in rodents. The calretinin-immunoreactive cells in this region were also immunoreactive for choline acetyltransferase. Evidence from other studies suggests that the calretinin region contributes to pathways involved in eye movement modulation but not generation. There were focal dense regions of fibers immunoreactive to calbindin in the medial and inferior nuclei, with an especially dense region of label at the border of the medial nucleus and the nucleus prepositus hypoglossi. There is anatomical evidence that suggests that the likely source of these calbindin-immunoreactive fibers is the flocculus of the cerebellum. The distribution of calbindin-immunoreactive fibers in the lateral and superior nuclei was much more uniform. Immunoreactivity to parvalbumin was widespread in fibers distributed throughout the VNC. The results suggest that neurochemical techniques may help to reveal the internal complexity in VNC organization.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, University at Buffalo, 123 Sherman Hall, Buffalo, NY, 14214-3078, USA.
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Sylvestre PA, Choi JTL, Cullen KE. Discharge dynamics of oculomotor neural integrator neurons during conjugate and disjunctive saccades and fixation. J Neurophysiol 2003; 90:739-54. [PMID: 12672779 DOI: 10.1152/jn.00123.2003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Burst-tonic (BT) neurons in the prepositus hypoglossi and adjacent medial vestibular nuclei are important elements of the neural integrator for horizontal eye movements. While the metrics of their discharges have been studied during conjugate saccades (where the eyes rotate with similar dynamics), their role during disjunctive saccades (where the eyes rotate with markedly different dynamics to account for differences in depths between saccadic targets) remains completely unexplored. In this report, we provide the first detailed quantification of the discharge dynamics of BT neurons during conjugate saccades, disjunctive saccades, and disjunctive fixation. We show that these neurons carry both significant eye position and eye velocity-related signals during conjugate saccades as well as smaller, yet important, "slide" and eye acceleration terms. Further, we demonstrate that a majority of BT neurons, during disjunctive fixation and disjunctive saccades, preferentially encode the position and the velocity of a single eye; only few BT neurons equally encode the movements of both eyes (i.e., have conjugate sensitivities). We argue that BT neurons in the nucleus prepositus hypoglossi/medial vestibular nucleus play an important role in the generation of unequal eye movements during disjunctive saccades, and carry appropriate information to shape the saccadic discharges of the abducens nucleus neurons to which they project.
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Affiliation(s)
- Pierre A Sylvestre
- Aerospace Medical Research Unit, Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Goldman MS, Kaneko CRS, Major G, Aksay E, Tank DW, Seung HS. Linear regression of eye velocity on eye position and head velocity suggests a common oculomotor neural integrator. J Neurophysiol 2002; 88:659-65. [PMID: 12163519 DOI: 10.1152/jn.2002.88.2.659] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The oculomotor system produces eye-position signals during fixations and head movements by integrating velocity-coded saccadic and vestibular inputs. A previous analysis of nucleus prepositus hypoglossi (nph) lesions in monkeys found that the integration time constant for maintaining fixations decreased, while that for the vestibulo-ocular reflex (VOR) did not. On this basis, it was concluded that saccadic inputs are integrated by the nph, but that the vestibular inputs are integrated elsewhere. We re-analyze the data from which this conclusion was drawn by performing a linear regression of eye velocity on eye position and head velocity to derive the time constant and velocity bias of an imperfect oculomotor neural integrator. The velocity-position regression procedure reveals that the integration time constants for both VOR and saccades decrease in tandem with consecutive nph lesions, consistent with the hypothesis of a single common integrator. The previous evaluation of the integrator time constant relied upon fitting methods that are prone to error in the presence of velocity bias and saccades. The algorithm used to evaluate imperfect fixations in the dark did not account for the nonzero null position of the eyes associated with velocity bias. The phase-shift analysis used in evaluating the response to sinusoidal vestibular input neglects the effect of saccadic resets of eye position on intersaccadic eye velocity, resulting in gross underestimates of the imperfections in integration during VOR. The linear regression method presented here is valid for both fixation and low head velocity VOR data and is easy to implement.
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Affiliation(s)
- Mark S Goldman
- Howard Hughes Medical Institute and Brain and Cognitive Sciences Department, Massachusetts Institute of Technology, Cambridge 02139, USA.
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35
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Arts MP, De Zeeuw CI, Lips J, Rosbak E, Simpson JI. Effects of nucleus prepositus hypoglossi lesions on visual climbing fiber activity in the rabbit flocculus. J Neurophysiol 2000; 84:2552-63. [PMID: 11067997 DOI: 10.1152/jn.2000.84.5.2552] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The caudal dorsal cap (dc) of the inferior olive is involved in the control of horizontal compensatory eye movements. It provides those climbing fibers to the vestibulocerebellum that modulate optimally to optokinetic stimulation about the vertical axis. This modulation is mediated at least in part via an excitatory input to the caudal dc from the pretectal nucleus of the optic tract and the dorsal terminal nucleus of the accessory optic system. In addition, the caudal dc receives a substantial GABAergic input from the nucleus prepositus hypoglossi (NPH). To investigate the possible contribution of this bilateral inhibitory projection to the visual responsiveness of caudal dc neurons, we recorded the climbing fiber activity (i.e., complex spikes) of vertical axis Purkinje cells in the flocculus of anesthetized rabbits before and after ablative lesions of the NPH. When the NPH ipsilateral to the recorded flocculus was lesioned, the spontaneous complex spike firing frequency did not change significantly; but when both NPHs were lesioned, the spontaneous complex spike firing frequency increased significantly. When only the contralateral NPH was lesioned, the spontaneous complex spike firing frequency decreased significantly. Neither unilateral nor bilateral lesions had a significant influence on the depth of complex spike modulation during constant velocity optokinetic stimulation or on the transient continuation of complex spike modulation that occurred when the constant velocity optokinetic stimulation stopped. The effects of the lesions on the spontaneous complex spike firing frequency could not be explained when only the projections from the NPH to the inferior olive were considered. Therefore we investigated at the electron microscopic level the nature of the commissural connection between the two NPHs. The terminals of this projection were found to be predominantly GABAergic and to terminate in part on GABAergic neurons. When this inhibitory commissural connection is taken into consideration, then the effects of NPH lesions on the spontaneous firing frequency of floccular complex spikes are qualitatively explicable in terms of relative weighting of the commissural and caudal dc projections of the NPH. In summary, we conclude that in the anesthetized rabbit the inhibitory projection of the NPH to the caudal dc influences the spontaneous firing frequency of floccular complex spikes but not their modulation by optokinetic stimulation.
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Affiliation(s)
- M P Arts
- Department of Physiology and Neuroscience, New York University School of Medicine, New York, New York 10016, USA
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36
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Aksay E, Baker R, Seung HS, Tank DW. Anatomy and discharge properties of pre-motor neurons in the goldfish medulla that have eye-position signals during fixations. J Neurophysiol 2000; 84:1035-49. [PMID: 10938326 DOI: 10.1152/jn.2000.84.2.1035] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous work in goldfish has suggested that the oculomotor velocity-to-position neural integrator for horizontal eye movements may be confined bilaterally to a distinct group of medullary neurons that show an eye-position signal. To establish this localization, the anatomy and discharge properties of these position neurons were characterized with single-cell Neurobiotin labeling and extracellular recording in awake goldfish while monitoring eye movements with the scleral search-coil method. All labeled somata (n = 9) were identified within a region of a medially located column of the inferior reticular formation that was approximately 350 microm in length, approximately 250 microm in depth, and approximately 125 microm in width. The dendrites of position neurons arborized over a wide extent of the ventral half of the medulla with especially heavy ramification in the initial 500 microm rostral of cell somata (n = 9). The axons either followed a well-defined ventral pathway toward the ipsilateral abducens (n = 4) or crossed the midline (n = 2) and projected toward the contralateral group of position neurons and the contralateral abducens. A mapping of the somatic region using extracellular single unit recording revealed that position neurons (n > 120) were the dominant eye-movement-related cell type in this area. Position neurons did not discharge below a threshold value of horizontal fixation position of the ipsilateral eye. Above this threshold, firing rates increased linearly with increasing temporal position [mean position sensitivity = 2.8 (spikes/s)/ degrees, n = 44]. For a given fixation position, average rates of firing were higher after a temporal saccade than a nasal one (n = 19/19); the magnitude of this hysteresis increased with increasing position sensitivity. Transitions in firing rate accompanying temporal saccades were overshooting (n = 43/44), beginning, on average, 17.2 ms before saccade onset (n = 17). Peak firing rate change accompanying temporal saccades was correlated with eye velocity (n = 36/41). The anatomical findings demonstrate that goldfish medullary position neurons have somata that are isolated from other parts of the oculomotor system, have dendritic fields overlapping with axonal terminations of neurons with velocity signals, and have axons that are capable of relaying commands to the abducens. The physiological findings demonstrate that the signals carried by position neurons could be used by motoneurons to set the fixation position of the eye. These results are consistent with a role for position neurons as elements of the velocity-to-position neural integrator for horizontal eye movements.
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Affiliation(s)
- E Aksay
- Biological Computation Research Department, Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974, USA
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37
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Abstract
OBJECTIVES To develop a hypothetical scheme to account for clinical disorders of vertical gaze based on recent insights gained from experimental studies. METHODS The authors critically reviewed reports of anatomy, physiology, and effects of pharmacologic inactivation of midbrain nuclei. RESULTS Vertical saccades are generated by burst neurons lying in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). Each burst neuron projects to motoneurons in a manner such that the eyes are tightly coordinated (yoked) during vertical saccades. Saccadic innervation from riMLF is unilateral to depressor muscles but bilateral to elevator muscles, with axons crossing within the oculomotor nucleus. Thus, riMLF lesions cause conjugate saccadic palsies that are usually either complete or selectively downward. Each riMLF contains burst neurons for both up and down saccades, but only for ipsilateral torsional saccades. Therefore, unilateral riMLF lesions can be detected at the bedside if torsional quick phases are absent during ipsidirectional head rotations in roll. The interstitial nucleus of Cajal (INC) is important for holding the eye in eccentric gaze after a vertical saccade and coordinating eye-head movements in roll. Bilateral INC lesions limit the range of vertical gaze. The posterior commissure (PC) is the route by which INC projects to ocular motoneurons. Inactivation of PC causes vertical gaze-evoked nystagmus, but destructive lesions cause a more profound defect of vertical gaze, probably due to involvement of the nucleus of the PC. Vestibular signals originating from each of the vertical labyrinthine canals ascend to the midbrain through several distinct pathways; normal vestibular function is best tested by rotating the patient's head in the planes of these canals. CONCLUSIONS Predictions of a current scheme to account for vertical gaze palsy can be tested at the bedside with systematic examination of each functional class of eye movements.
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Affiliation(s)
- R Bhidayasiri
- Department of Neurology, Department of Veterans Affairs Medical Center and University Hospitals, Case Western Reserve University, Cleveland, OH 44106-5040, USA
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Seung HS, Lee DD, Reis BY, Tank DW. Stability of the memory of eye position in a recurrent network of conductance-based model neurons. Neuron 2000; 26:259-71. [PMID: 10798409 DOI: 10.1016/s0896-6273(00)81155-1] [Citation(s) in RCA: 234] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Studies of the neural correlates of short-term memory in a wide variety of brain areas have found that transient inputs can cause persistent changes in rates of action potential firing, through a mechanism that remains unknown. In a premotor area that is responsible for holding the eyes still during fixation, persistent neural firing encodes the angular position of the eyes in a characteristic manner: below a threshold position the neuron is silent, and above it the firing rate is linearly related to position. Both the threshold and linear slope vary from neuron to neuron. We have reproduced this behavior in a biophysically plausible network model. Persistence depends on precise tuning of the strength of synaptic feedback, and a relatively long synaptic time constant improves the robustness to mistuning.
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Affiliation(s)
- H S Seung
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139, USA
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Priesol AJ, Jones GE, Tomlinson RD, Broussard DM. Frequency-dependent effects of glutamate antagonists on the vestibulo-ocular reflex of the cat. Brain Res 2000; 857:252-64. [PMID: 10700574 DOI: 10.1016/s0006-8993(99)02441-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the central nervous system, sensory and motor signals at different frequencies are transmitted most effectively by neural elements that have different dynamic characteristics. Dynamic differences may be due, in part, to the dynamics of neurotransmitter receptors. For example, N-methyl-D-aspartate (NMDA) receptors are thought to be a component of the "neural integrator" of the vestibulo-ocular reflex (VOR), which generates a signal proportional to eye position. We measured the effects of blockade of NMDA and AMPA/kainate receptors on the gain and phase of the VOR at frequencies between 0.1 and 8 Hz in alert cats. The competitive NMDA antagonist, APV, and the non-competitive antagonists, MK-801 and ketamine, all caused a pronounced reduction in VOR gain. Gain was more strongly attenuated at low frequencies (0.1-1 Hz) than at higher frequencies (2-8 Hz). The phase lead of the eye with respect to the head was increased up to 30 degrees. In contrast, the reduction in gain associated with drowsiness or surgical anesthesia was not frequency-dependent. Blockade of AMPA/kainate receptors by the competitive antagonists, CNQX and NBQX, reduced the gain of the VOR at all frequencies tested. We evaluated our results using a control systems model. Our data are consistent with participation of NMDA receptors in neural integration, but suggest that NMDA receptors also participate in transmission by other components of the VOR pathway, and that neural integration also employs other receptors. One possibility is that between 0.1 and 10 Hz, higher-frequency signals are transmitted primarily by AMPA/kainate receptors, and lower frequencies by NMDA receptors. This arrangement would provide a biological substrate for selective motor learning within a small frequency range.
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Affiliation(s)
- A J Priesol
- Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
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