Spatial distribution of semicircular canal nerve evoked monosynaptic response components in frog vestibular nuclei

Straka, Hans; Biesdorf, Stefan; Dieringer, N.

doi:10.1016/s0006-8993(00)02768-2

Cited by 18 publications

(32 citation statements)

References 35 publications

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“…Some of these differences might be related to differences in the recorded population of 2°VN. In our study, recorded neurons were equally distributed throughout the vestibular nuclear complex as in former studies (see Straka et al 1997Straka et al , 2000. Recordings in the cat, however, were obtained predominantly in the lateral and descending vestibular nucleus and only to a minor degree in the superior and medial vestibular nucleus Sato et al 2000;Zakir et al 2000;Zhang et al 2001).…”

Section: Convergence Pattern Of Afferent Otolith and Canal Signals Insupporting

confidence: 65%

“…During intracellular recordings, the stimulation intensity to evoke an antidromic spike was limited to 4 ϫ T. Vestibular neurons were recorded between 0.5 mm rostral and 0.8 mm caudal to the entry of the VIIIth nerve in a depth between 0.05 mm and 0.8 mm below the dorsal surface of the brain stem. This recording area included the superior, lateral, and descending vestibular nucleus and excluded the most medial parts of the medial vestibular nucleus (see Straka et al 2000). All vestibular neurons recorded in the isolated frog brain in this study were not spontaneously active as in earlier studies Dieringer 1996, 2000;Straka et al 1997), and only those with a membrane potential more than Ϫ55 mV (range: Ϫ55 to Ϫ81 mV) and amplitudes of evoked action potentials Ͼ60 mV (range: Ϫ60 to Ϫ90 mV) were included in this study.…”

Section: E T H O D Smentioning

confidence: 99%

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Patterns of Canal and Otolith Afferent Input Convergence in Frog Second-Order Vestibular Neurons

Straka

Holler

Goto

2002

Journal of Neurophysiology

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Straka, H., S. Holler, and F. Goto. Patterns of canal and otolith afferent input convergence in frog second-order vestibular neurons. J Neurophysiol 88: 2287-2301, 2002 10.1152/jn.00370.2002 were identified in the isolated frog brain by the presence of monosynaptic excitatory postsynaptic potentials (EPSPs) after separate electrical stimulation of individual vestibular nerve branches. Combinations of one macular and the three semicircular canal nerve branches or combinations of two macular nerve branches were stimulated separately in different sets of experiments. Monosynaptic EPSPs evoked from the utricle or from the lagena converged with monosynaptic EPSPs from one of the three semicircular canal organs in ϳ30% of 2°VN. Utricular afferent signals converged predominantly with horizontal canal afferent signals (74%), and lagenar afferent signals converged with anterior vertical (63%) or posterior vertical (37%) but not with horizontal canal afferent signals. This convergence pattern correlates with the coactivation of particular combinations of canal and otolith organs during natural head movements. A convergence of afferent saccular and canal signals was restricted to very few 2°VN (3%). In contrast to the considerable number of 2°VN that received an afferent input from the utricle or the lagena as well as from one of the three canal nerves (ϳ30%), smaller numbers of 2°VN (14% of each type of 2°otolith or 2°canal neuron) received an afferent input from only one particular otolith organ or from only one particular semicircular canal organ. Even fewer 2°VN received an afferent input from more than one semicircular canal or from more than one otolith nerve (ϳ7% each). Among 2°VN with afferent inputs from more than one otolith nerve, an afferent saccular nerve input was particularly rare (4 -5%). The restricted convergence of afferent saccular inputs with other afferent otolith or canal inputs as well as the termination pattern of saccular afferent fibers are compatible with a substrate vibration sensitivity of this otolith organ in frog. The ascending and/or descending projections of identified 2°VN were determined by the presence of antidromic spikes. 2°VN mediating afferent utricular and/or semicircular canal nerve signals had ascending and/or descending axons. 2°VN mediating afferent lagenar or saccular nerve signals had descending but no ascending axons. The latter result is consistent with the absence of short-latency macular signals on extraocular motoneurons during vertical linear acceleration. Comparison of data from frog and cat demonstrated the presence of a similar organization pattern of maculo-and canal-ocular reflexes in both species. I N T R O D U C T I O NComponents of linear and angular head acceleration are detected separately by the different otolith and semicircular canal organs in the labyrinth. These signals are mediated in parallel pathways by afferent nerve fibers to the vestibular nuclei, the brain stem reticular formation, and the cerebellum. Afferent nerve fibers from individual semicirc...

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Section: Convergence Pattern Of Afferent Otolith and Canal Signals Insupporting

confidence: 65%

Section: E T H O D Smentioning

confidence: 99%

Patterns of Canal and Otolith Afferent Input Convergence in Frog Second-Order Vestibular Neurons

Straka

Holler

Goto

2002

Journal of Neurophysiology

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“…It is generally agreed that, in their central representation, each endorgans has a domain of almost exclusive projection and a domain of sparse projection overlapping with other endorgans, reproducing the peripheral distribution pattern at the level of the ganglion [16,26,59,68,75]. Such a partial functional as well as anatomical overlap is best known for the frog [9,92,93]. This central overlapping pattern may be a universal functional feature of the vestibular system to converge monosynaptically afferent canal and otolith inputs [93] to integrate multiple inputs, and yet to respond in precise and finely graded fashion to unique signals (Newlands and Perachio, this volume).…”

Section: Establishing Central Connectionsmentioning

confidence: 95%

Development of vestibular afferent projections into the hindbrain and their central targets

Maklad

Fritzsch

2003

Brain Research Bulletin

113

114

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In contrast to most other sensory systems, hardly anything is known about the neuroanatomical development of central projections of primary vestibular neurons and how their second order target neurons develop. Recent data suggest that afferent projections may develop not unlike other sensory systems, forming first the overall projection by molecular means followed by an as yet unspecified phase of activity mediated refinement. The latter aspect has not been tested critically and most molecules that guide the initial projection are unknown.The molecular and topological origin of the vestibular and cochlear nucleus neurons is also only partially understood. Auditory and vestibular nuclei form from several rhombomeres and a given rhombomere can contribute to two or more auditory or vestibular nuclei. Rhombomere compartments develop as functional subdivisions from a single column that extends from the hindbrain to the spinal cord. Suggestions are provided for the molecular origin of these columns but data on specific mutants testing these proposals are not yet available. Overall, the functional significance of both overlapping and segregated projections are not yet fully experimentally explored in mammals. Such lack of details of the adult organization compromises future developmental analysis.

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Section: Introductionmentioning

confidence: 98%

“…Similarities between mammalian and frog semicircular canal pathways extend from general patterns of afferent fiber projections down to precise locations within vestibular nuclei of canal-specific premotor projection neurons (Baker 1998;Birinyi et al 2001;Büttner-Ennever 1992;Straka et al 2000a). In frog, afferent nerve fibers from individual semicircular canals terminate differentially in the four major vestibular subnuclei (Birinyi et al 2001) in patterns that quantitatively match the spatial distribution of semicircular canal nerve-evoked monosynaptic responses as well as the locations of identified 2°canal neurons (Straka et al 2000a). Intracellular recordings demonstrated that monosynaptic responses of 2°VN predominately originated from only one ipsilateral semicircular canal in frog (Holler and Straka 2001;Straka et al 1997Straka et al , 2002b as in pigeon (Wilson and Felpel 1972) and cat (Kasahara and Uchino 1974;Sans et al 1972;Sato et al 2002).…”

Section: Introductionmentioning

confidence: 98%

Differential Spatial Organization of Otolith Signals in Frog Vestibular Nuclei

Holler¹,

Goto²,

Kolb³

et al. 2003

Journal of Neurophysiology

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. Activation maps of pre-and postsynaptic field potential components evoked by separate electrical stimulation of utricular, lagenar, and saccular nerve branches in the isolated frog hindbrain were recorded within a stereotactic outline of the vestibular nuclei. Utricular and lagenar nerveevoked activation maps overlapped strongly in the lateral and descending vestibular nuclei, whereas lagenar amplitudes were greater in the superior vestibular nucleus. In contrast, the saccular nerveevoked activation map coincided largely with the dorsal nucleus and the adjacent dorsal part of the lateral vestibular nucleus, corroborating a major auditory and lesser vestibular function of the frog saccule. The stereotactic position of individual second-order otolith neurons matched the distribution of the corresponding otolith nerve-evoked activation maps. Furthermore, particular types of second-order utricular and lagenar neurons were clustered with particular types of second-order canal neurons in a topology that anatomically mirrored the preferred convergence pattern of afferent otolith and canal signals in second-order vestibular neurons. Similarities in the spatial organization of functionally equivalent types of second-order otolith and canal neurons between frog and other vertebrates indicated conservation of a common topographical organization principle. However, the absence of a precise afferent sensory topography combined with the presence of spatially segregated groups of particular second-order vestibular neurons suggests that the vestibular circuitry is organized as a premotor map rather than an organotypical sensory map. Moreover, the conserved segmental location of individual vestibular neuronal phenotypes shows linkage of individual components of vestibulomotor pathways with the underlying genetically specified rhombomeric framework.

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Spatial distribution of semicircular canal nerve evoked monosynaptic response components in frog vestibular nuclei

Cited by 18 publications

References 35 publications

Patterns of Canal and Otolith Afferent Input Convergence in Frog Second-Order Vestibular Neurons

Patterns of Canal and Otolith Afferent Input Convergence in Frog Second-Order Vestibular Neurons

Development of vestibular afferent projections into the hindbrain and their central targets

Differential Spatial Organization of Otolith Signals in Frog Vestibular Nuclei

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