Extraocular muscles involved in convergence are innervated by an additional set of palisade endings that may differ in their excitability: A human study

Lienbacher, Karoline; Sänger, Kathrin; Strassburger, Sebastian; Ehrt, Oliver; Rudolph, Günther; Barnerssoi, Miriam; Horn, Anja K. E.

doi:10.1016/bs.pbr.2019.04.005

Cited by 10 publications

(16 citation statements)

References 30 publications

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“…That palisade endings originate from sensory-like neurons has been proposed in the two previous studies. 18,19 Specifically, following distal EOM tracer injection, involving the palisade zone and en grappe motor terminals, two morphologically distinct populations of neurons have been identified in the EOM motor nuclei of monkeys: multipolar neurons and another group, resembling spindleshaped neurons. It has been assumed that the latter group, which might be similar to mesencephalic sensory neurons, is the source of palisade endings.…”

Section: Anatomical Verification Of Continuity Between Mif Inputs Andmentioning

confidence: 99%

“…It has been assumed that the latter group, which might be similar to mesencephalic sensory neurons, is the source of palisade endings. 18,19 If this is true, sensory nerve fibers with molecular characteristics of motoneurons and MIF motoneuron innervations pattern, would supply palisade endings. As a consequence, this would mean that MIF motoneurons are both sensory and motor, which, however, does not seem to be easily compatible.…”

Section: Anatomical Verification Of Continuity Between Mif Inputs Andmentioning

confidence: 99%

“…8,35 Further, in two primate species (man and monkey) many palisade endings located in the medial rectus muscle and a lower number of palisade endings of the inferior rectus muscle express calretinin, whereas palisade endings of the other two rectus muscles lack calretinin. 19,34 Calretinin is a calcium-blinding protein and, although its functional role is unclear, the authors have hypothesized that calretinin-positive palisade endings represent a specialized, probable more excitable, type of palisade ending needed for convergent eye movement. 19,34 Recently, it has been demonstrated that MIF motoneurons participate in the whole repertoire of eye movements.…”

Section: Functional Considerationsmentioning

confidence: 99%

“…19,34 Calretinin is a calcium-blinding protein and, although its functional role is unclear, the authors have hypothesized that calretinin-positive palisade endings represent a specialized, probable more excitable, type of palisade ending needed for convergent eye movement. 19,34 Recently, it has been demonstrated that MIF motoneurons participate in the whole repertoire of eye movements. 49 Due to the fact that palisade endings are extensions of MIF motoneurons axons, this suggests that palisade endings despite their unknown function, are relevant for all types of eye movement.…”

Section: Functional Considerationsmentioning

confidence: 99%

“…[15][16][17] Other studies suggest that palisade endings might arise from a separate population of neurons in the oculomotor nuclei with morphology reminiscent of sensory pseudounipolar neurons. 18,19 So far, no receptors for cholinergic transmission (i.e. acetylcholine receptors [AChR]), have been found on muscle fibers opposed to palisade endings in investigated species with the exception of rabbits and rats, 20 whose palisade endings, however, have a simplified morphology.…”

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confidence: 99%

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Palisade Endings Have an Exocytotic Machinery But Lack Acetylcholine Receptors and Distinct Acetylcholinesterase Activity

Blumer

Streicher

Carrero-Rojas

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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Section: Anatomical Verification Of Continuity Between Mif Inputs Andmentioning

confidence: 99%

Section: Anatomical Verification Of Continuity Between Mif Inputs Andmentioning

confidence: 99%

Section: Functional Considerationsmentioning

confidence: 99%

Section: Functional Considerationsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Palisade Endings Have an Exocytotic Machinery But Lack Acetylcholine Receptors and Distinct Acetylcholinesterase Activity

Blumer

Streicher

Carrero-Rojas

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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Proprioceptive contribution to oculomotor control in humans

Balslev

Mitchell

Faria

et al. 2022

Human Brain Mapping

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Stretch receptors in the extraocular muscles (EOMs) inform the central nervous system about the rotation of one's own eyes in the orbits. Whereas fine control of the skeletal muscles hinges critically on proprioceptive feedback, the role of proprioception in oculomotor control remains unclear. Human behavioural studies provide evidence for EOM proprioception in oculomotor control, however, behavioural and electrophysiological studies in the macaque do not. Unlike macaques, humans possess numerous muscle spindles in their EOMs. To find out whether the human oculomotor nuclei respond to proprioceptive feedback we used functional magnetic resonance imaging (fMRI). With their eyes closed, participants placed their right index finger on the eyelid at the outer corner of the right eye. When prompted by a sound, they pushed the eyeball gently and briefly towards the nose. Control conditions separated out motor and tactile task components. The stretch of the right lateral rectus muscle was associated with activation of the left oculomotor nucleus and subthreshold activation of the left abducens nucleus. Because these nuclei control the horizontal movements of the left eye, we hypothesized that proprioceptive stimulation of the right EOM triggered left eye movement. To test this, we followed up with an eye-tracking experiment in complete darkness using the same behavioural task as in the fMRI study. The left eye moved actively in the direction of the passive displacement of the right eye, albeit with a smaller amplitude. Eye tracking corroborated neuroimaging findings to suggest a proprioceptive contribution to ocular alignment.

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Spinal cord from body donors is suitable for multicolor immunofluorescence

Reissig

Carrero-Rojas

Maierhofer

et al. 2022

Histochem Cell Biol

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Immunohistochemistry is a powerful tool for studying neuronal tissue from humans at the molecular level. Obtaining fresh neuronal tissue from human organ donors is difficult and sometimes impossible. In anatomical body donations, neuronal tissue is dedicated to research purposes and because of its easier availability, it may be an alternative source for research. In this study, we harvested spinal cord from a single organ donor 2 h (h) postmortem and spinal cord from body donors 24, 48, and 72 h postmortem and tested how long after death, valid multi-color immunofluorescence or horseradish peroxidase (HRP) immunohistochemistry is possible. We used general and specific neuronal markers and glial markers for immunolabeling experiments. Here we showed that it is possible to visualize molecularly different neuronal elements with high precision in the body donor spinal cord 24 h postmortem and the quality of the image data was comparable to those from the fresh organ donor spinal cord. High-contrast multicolor images of the 24-h spinal cords allowed accurate automated quantification of different neuronal elements in the same sample. Although there was antibody-specific signal reduction over postmortem intervals, the signal quality for most antibodies was acceptable at 48 h but no longer at 72 h postmortem. In conclusion, our study has defined a postmortem time window of more than 24 h during which valid immunohistochemical information can be obtained from the body donor spinal cord. Due to the easier availability, neuronal tissue from body donors is an alternative source for basic and clinical research.

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Extraocular muscles involved in convergence are innervated by an additional set of palisade endings that may differ in their excitability: A human study

Cited by 10 publications

References 30 publications

Palisade Endings Have an Exocytotic Machinery But Lack Acetylcholine Receptors and Distinct Acetylcholinesterase Activity

Palisade Endings Have an Exocytotic Machinery But Lack Acetylcholine Receptors and Distinct Acetylcholinesterase Activity

Proprioceptive contribution to oculomotor control in humans

Spinal cord from body donors is suitable for multicolor immunofluorescence

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