Distribution of the Vestibular Neurons Projecting to the Oculomotor and Trochlear Nuclei in Rabbits

Labandeira‐Garcia, Jose L.; Guerra-Seijas, M.J.; Labandeira-García, Javier; Barreiro, F.

doi:10.1159/000114352

Cited by 19 publications

(10 citation statements)

References 23 publications

(56 reference statements)

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“…These findings agree with the present observations that only floccular zones 1 and 3, which are involved in the vertical compensatory eye movements (i.e., eye movements dominated by the vertical recti and oblique muscles), project to the SVN (see also Van Der Steen et al, 1991;Simpson et al, 1992). The excitatory second-order flocculi receiving neurons in the SVN innervate contralateral superior rectus and inferior oblique motoneurons, whereas the inhibitory ones innervate ipsilateral inferior rectus and superior oblique motoneurons (Highstein, 1973a;Ito et al, 1976;Yamamoto et al, 1978;Highstein and Reisine, 1979;Sat0 and Kawasaki, 1990b;Labandeira-Garcia et al, 1991).…”

Section: Open and Closed Anatomical Pathways Involved In Compensatorysupporting

confidence: 91%

Projections of individual purkinje cells of identified zones in the flocculus to the vestibular and cerebellar nuclei in the rabbit

Wylie

Zeeuw

DiGiorgi

et al. 1994

J of Comparative Neurology

205

118

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The rabbit flocculus can be divided into five zones (zones 1, 2, 3, 4, and C2) with the use of acetylcholinesterase histochemistry. The projections of individual Purkinje cells in these zones to the vestibular and cerebellar nuclei were studied by using biocytin as an anterograde tracer. The zones were physiologically identified in terms of the Purkinje cell complex spike modulation occurring in response to optokinetic stimulation. In zones 1 and 3 neurons respond best to rotation about a horizontal axis that is close to perpendicular to the ipsilateral anterior semicircular canal, whereas in zones 2 and 4 neurons respond best to rotation about the vertical axis. Complex spike activity in zone C2 is unresponsive to optokinetic stimulation. Collectively, Purkinje cells of zone 1 projected to the ventral dentate nucleus, dorsal group y, and superior vestibular nucleus; Purkinje cells of zones 2 and 4 projected to the magnocellular and parvicellular parts of the medial vestibular nucleus; Purkinje cells of zone 3 projected to dorsal group y, ventral group y, and the superior vestibular nucleus; and Purkinje cells of zone C2 projected to the interposed posterior nucleus and dorsal group y. Some of the labeled Purkinje cell axons branched and innervated two nuclei. Branching axons from zone 1 either innervated both the ventral dentate nucleus and the superior vestibular nucleus or both dorsal group y and the superior vestibular nucleus. Branching axons from zones 2 and 4 innervated both the magnocellular and the parvicellular parts of the medial vestibular nucleus. Branching axons from zone 3 innervated both dorsal group y and the superior vestibular nucleus, or both ventral group y and the superior vestibular nucleus. Branching axons from zone C2 innervated both the interposed posterior nucleus and dorsal group y. Some of the target nuclei of the floccular Purkinje cell axons (e.g., dorsal group y and interposed posterior nucleus) project to the part of the inferior olive that, in turn, projects to the corresponding floccular zone, thus completing a closed pathway consisting of the inferior olive, the cerebellar cortex, and the cerebellar and vestibular nuclei. Other target nuclei (e.g., superior vestibular nucleus and medial vestibular nucleus) do not project back to the olivary subnuclei that innervate the flocculus and are part of an open olivofloccular pathway. An individual Purkinje cell thus can innervate a nucleus in the closed pathway as well as a nucleus in the open pathway.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Open and Closed Anatomical Pathways Involved In Compensatorysupporting

confidence: 91%

Projections of individual purkinje cells of identified zones in the flocculus to the vestibular and cerebellar nuclei in the rabbit

Wylie

Zeeuw

DiGiorgi

et al. 1994

J of Comparative Neurology

205

118

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“…Except for the flatfish, which shows adaptive changes in the pattern of vestibulo-oculomotor connections at metamorphosis Baker, 1983, 1985, 19901, the basic pattern of secondary vestibular projection to the oculomotor nucleus appears to be similar to that reported for other vertebrates, in which the oculomotor nucleus receives mainly ipsilateral projections from the anterior (or superior) octaval nucleus and contralateral projections from the magnocellular and descending octaval nucleus (amphibians, Will et al, 1985;Will, 1988;Gonzalez and Munoz, 1989;reptiles, Bangma and ten Donkelaar, 1983;ten Donkelaar et al, 1985;birds, Wold, 1978;Labandeira-Garcia et al, 1989;Petursdbttir, 1990;mammals, Graybiel and Hartwieg, 1974;Gaceck, 1977;Steiger and Buttner-Ennever, 1979;Carleton and Carpenter, 1983;Carpenter and Cowie, 1985;Labandeira-Garciaet al, 1991). Our results in lamprey, however, show that projections from the AON to the oculomotor nucleus are predominantly contralateral, while projections from the ION are mainly ipsilateral, and there are no vestibulo-oculomotor projections from the PON (Pombal et al, 1994b).…”

Section: Comparison With Other Vertebratessupporting

confidence: 73%

Secondary vestibulo-oculomotor projections in larval sea lamprey: Anterior octavomotor nucleus

Pombal

Rodicio

Anadón³

1996

J. Comp. Neurol.

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The ventral octavolateral area of lampreys contains three nuclei: the anterior, intermediate and posterior octavomotor nuclei, formed of large neurons that are contacted by thick primary vestibular fibres. We used horseradish peroxidase (HRP) or fluorescein-dextran-amine (FDA) labelling to study the projections of the anterior octavomotor nucleus (AON) in the larval sea lamprey, Petromyzon marinus. The tracers were injected either in the AON, the oculomotor nucleus or the rostralmost spinal cord. HRP injection in the AON labelled thick axons that coursed to the basal mesencephalic tegmentum, where most decussate and project to the oculomotor nucleus and the third Müller cell. Electron microscopy confirmed that AON axons contact with the contralateral third Müller cell and with oculomotor neurons. Some AON axons run in the mesencephalic tegmentum and the ventral diencephalon. An AON axon was observed to run close to the axon of the contralateral third Müller cell, establishing what appeared to be en passant contacts. HRP injection in the AON also revealed commissural fibres projecting to the contralateral octavolateral area. HRP or FDA injections in the oculomotor nucleus labelled both large and small neurons of the AON, mostly contralateral to the injection site, as well as of cells in the intermediate octavomotor nucleus, mainly ipsilateral. HRP injection in the AON or in the rostral spinal cord did not reveal any projections from the AON to the spinal cord. Our results indicate that the pattern of octavo-oculomotor connections in the lamprey is different from that observed in other vertebrates.

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“…Premotor neurons to the abducens and trochlear motor nuclei are also in the pontine reticular formation (699,1115,1344,1420). All three motor nuclei receive input from the vestibular nuclei as part of the vestibulo-ocular reflex (225,341,434,685,699,943,1051,1283). Some of these premotor neurons are GABAergic (superior vestibular nucleus) or cholinergic (the medial vestibular nucleus; Refs.…”

Section: B Afferent Projections To Orofacial Motor Nucleimentioning

confidence: 99%

“…Some of these premotor neurons are GABAergic (superior vestibular nucleus) or cholinergic (the medial vestibular nucleus; Refs. 191,685,1346). Coordination between motoneurons in the oculomotor and abducens nuclei is partly mediated by GABAergic internuclear neurons projecting contralaterally between the nuclei (284,817,1346).…”

Section: B Afferent Projections To Orofacial Motor Nucleimentioning

confidence: 99%

Synaptic Control of Motoneuronal Excitability

Rekling

Funk

Bayliss

et al. 2000

Physiological Reviews

531

482

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Movement, the fundamental component of behavior and the principal extrinsic action of the brain, is produced when skeletal muscles contract and relax in response to patterns of action potentials generated by motoneurons. The processes that determine the firing behavior of motoneurons are therefore important in understanding the transformation of neural activity to motor behavior. Here, we review recent studies on the control of motoneuronal excitability, focusing on synaptic and cellular properties. We first present a background description of motoneurons: their development, anatomical organization, and membrane properties, both passive and active. We then describe the general anatomical organization of synaptic input to motoneurons, followed by a description of the major transmitter systems that affect motoneuronal excitability, including ligands, receptor distribution, pre-and postsynaptic actions, signal transduction, and functional role. Glutamate is the main excitatory, and GABA and glycine are the main inhibitory transmitters acting through ionotropic receptors. These amino acids signal the principal motor commands from peripheral, spinal, and supraspinal structures. Amines, such as serotonin and norepinephrine, and neuropeptides, as well as the glutamate and GABA acting at metabotropic receptors, modulate motoneuronal excitability through pre-and postsynaptic actions. Acting principally via second messenger systems, their actions converge on common effectors, e.g., leak K + current, cationic inward current, hyperpolarization-activated inward current, Ca 2+ channels, or presynaptic release processes. Together, these numerous inputs mediate and modify incoming motor commands, ultimately generating the coordinated firing patterns that underlie muscle contractions during motor behavior.

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Distribution of the Vestibular Neurons Projecting to the Oculomotor and Trochlear Nuclei in Rabbits

Cited by 19 publications

References 23 publications

Projections of individual purkinje cells of identified zones in the flocculus to the vestibular and cerebellar nuclei in the rabbit

Projections of individual purkinje cells of identified zones in the flocculus to the vestibular and cerebellar nuclei in the rabbit

Secondary vestibulo-oculomotor projections in larval sea lamprey: Anterior octavomotor nucleus

Synaptic Control of Motoneuronal Excitability

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