Bilateral innervation of the superior oblique muscle by the trochlear nucleus

Miyazaki, Shigeo

doi:10.1016/0006-8993(85)90358-0

Cited by 27 publications

(6 citation statements)

References 15 publications

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“…Consequentially, we would incorrectly label any ipsilaterally innervating SO or SR motoneurons or contralaterally innervating IO, IR, or MR motoneurons. Several earlier studies have reported infrequent ipsilateral innervation of SO or SR, by <5% of the total motoneuron pool in each case (Luiten and de Vlieger, ; Graf and Baker, ; Miyazaki, ; Murphy et al, ; Evinger et al, ; Sonntag and Fritzsch, ; Sun and May, ), and one study reported rare contralateral IR motoneurons (El Hassni et al, ). The low numbers seen in other organisms lead us to believe that few, if any, motoneurons were incorrectly labeled in our study.…”

Section: Discussionmentioning

confidence: 94%

Extraocular motoneuron pools develop along a dorsoventral axis in zebrafish, Danio rerio

Greaney

Privorotskiy

D’Elia

et al. 2016

J of Comparative Neurology

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Both spatial and temporal cues determine the fate of immature neurons. A major challenge at the interface of developmental and systems neuroscience is to relate this spatiotemporal trajectory of maturation to circuit‐level functional organization. This study examined the development of two extraocular motor nuclei (nIII and nIV), structures in which a motoneuron's identity, or choice of muscle partner, defines its behavioral role. We used retro‐orbital dye fills, in combination with fluorescent markers for motoneuron location and birthdate, to probe spatial and temporal organization of the oculomotor (nIII) and trochlear (nIV) nuclei in the larval zebrafish. We describe a dorsoventral organization of the four nIII motoneuron pools, in which inferior and medial rectus motoneurons occupy dorsal nIII, while inferior oblique and superior rectus motoneurons occupy distinct divisions of ventral nIII. Dorsal nIII motoneurons are, moreover, born before motoneurons of ventral nIII and nIV. The order of neurogenesis can therefore account for the dorsoventral organization of nIII and may play a primary role in determining motoneuron identity. We propose that the temporal development of extraocular motoneurons plays a key role in assembling a functional oculomotor circuit. J. Comp. Neurol. 525:65–78, 2017. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

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Section: Discussionmentioning

confidence: 94%

Extraocular motoneuron pools develop along a dorsoventral axis in zebrafish, Danio rerio

Greaney

Privorotskiy

D’Elia

et al. 2016

J of Comparative Neurology

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“…The trochlear nucleus consists of ϳ100 motoneurons in the frog (Knöpfel et al 1984), 400 in rat (Eberhorn et al 2006), and 900 in rabbit (Miyazaki 1985;Murphy et al 1986). Thus the turtle Ncl.…”

Section: Morphology Of the Turtle Ncl IVmentioning

confidence: 99%

Morphology, Intrinsic Membrane Properties, and Rotation-Evoked Responses of Trochlear Motoneurons in the Turtle

Jones¹,

Ariel²

2008

Journal of Neurophysiology

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Jones MS, Ariel M. Morphology, intrinsic membrane properties, and rotation-evoked responses of trochlear motoneurons in the turtle. J Neurophysiol 99: 1187-1200, 2008. First published December 26, 2007 doi:10.1152/jn.01205.2007. Intrinsic properties and rotationevoked responses of trochlear motoneurons were investigated in the turtle using an in vitro preparation consisting of the brain stem with attached temporal bones that retain functional semicircular canals. Motoneurons were divided into two classes based on intrinsic properties. The first class exhibited higher impedance (123.0 Ϯ 11.0 M⍀), wider spikes (0.99 Ϯ 0.05 ms), a single spike afterhyperpolarization (AHP), little or no spike frequency adaptation (SFA), and anomalous rectification, characterized by an initial "sag" in membrane potential in response to hyperpolarizing current injection. The second class exhibited lower impedance (21.8 Ϯ 2.5 M⍀), narrower spikes (0.74 Ϯ 0.03 ms), a double AHP, substantial SFA, and little or no rectification. Vestibular responses were evoked by horizontal sinusoidal rotation (1/12-1/3 Hz; peak velocity: 30 -100°/s). Spiking in higher-impedance cells was recruited earlier in the response and exhibited a more limited dynamic range relative to that of lower impedance cells. Spiking evoked by injecting depolarizing current during rotation was blocked during contraversive motion and was consistent with a shunting inhibition. No morphological features were identified in neurobiotinfilled cells that correlated with the two physiological classes. Recovered motoneurons were multipolar but exhibited a less-complex dendritic morphology than ocular motoneurons of similarly sized mammals. The two physiologically defined cell classes have homologues in other vertebrates, suggesting that intrinsic membrane properties play an important role in oculomotor processing. I N T R O D U C T I O NMotoneurons in the oculomotor, trochlear, and abducens nuclei comprise the common final output pathway for the control of eye movement. A variety of descending and brain stem projections converge on these motoneurons (ButtnerEnnever and Horn 1997), which transform a complex spatiotemporal pattern of synaptic input into a rate-coded spike train that drives the extraocular muscles in a coordinated and precise fashion. These neurons are not only responsible for the generation of voluntary eye movements but also participate in critical brain stem reflexes such as the vestibuloocular reflex (VOR), a compensatory movement of the eyes during motion of the head that acts to stabilize the visual scene on the retina (Wilson and Melvill-Jones 1976).There has been intensive study of oculomotor physiology and the VOR over the last few decades, motivated not only by its clinical relevance but also the utility of the system as a model of neural control (Schwarz 1976;Young 1995). One issue that remains poorly understood is the role of intrinsic membrane properties in shaping motoneuron output. In the spinal cord, the role of intrinsic properties in influencing syna...

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“…1986). The decussation of the trochlear nerve is not complete: 5 o/o of the motoneurons in the cat and rabbit give rise to uncrossed projections (Miyazaki 1985a;Murphy eta!. 1988).…”

Section: Eye Muscle Nucleimentioning

confidence: 99%