Absence of muscle spindles in avian extraocular muscles

Maier, Andrea B.; Santis, Mark De; Eldred, Earl

doi:10.1016/0014-4835(71)90145-x

Cited by 14 publications

(7 citation statements)

References 8 publications

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“…The amplitude (position) sensitivity measured when the eye had reached its ¢nal, de£ected position, ranged from 0.9 to 8 impulses s 71 deg 71 ; these values were una¡ected by the velocity with which the eye was displaced. These position sensitivities are rather similar to the range in the goat and perhaps the cat (see above) and it is interesting that the maximum sensitivity in the pigeon, which has no spindles in its EOM (Maier et al 1971), is at least as great as that recorded from ungulate EOM spindles under maximum gamma drive. During the displacement, units were found to show velocity sensitivity, though this seems rather smallöthe maximum was 0.2 impulses s 71 deg 71 .…”

Section: (Iv) Pigeonsupporting

confidence: 64%

“…We shall have occasion to discuss all these in detail later. Although we do know that they do not include muscle spindles (Maier et al 1971), we know nothing positive about the morphology of the pigeon EOM receptors. In other speciesöungulates, cats, monkeys and Manöwe do know of a range of receptors that the EOM have at their disposal, so to speak.…”

Section: (D) Other Endingsmentioning

confidence: 97%

“…Cats have no spindles in their EOM (Maier et al 1974) but make saccades, have a VOR that has been extensively studied, and optokinetic nystagmus (OKN) and most cats show vergence also (Hughes 1972). Pigeons have saccades of eyes as well as head (Bloch et al 1981;Lemeignan et al 1992; I. M. L. Donaldson, unpublished data), VOR (Anastasio & Correia 1988;Gioanni 1988a) and OKN (Gioanni 1988b) and an intriguingly fast vergence to targets in the binocular ¢eld (Bloch et al 1984(Bloch et al , 1987ö their EOM contain no muscle spindles (Maier et al 1971). No doubt these examples could be multiplied but they are su¤cient to leave no doubt that there is no simple correlation between the possession of eye muscle spindles and complexity of oculomotor repertoire.…”

Section: Why Do Some Animals Have Muscle Spindles In Their Extraoculamentioning

confidence: 99%

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The functions of the proprioceptors of the eye muscles

Donaldson

2000

Phil. Trans. R. Soc. Lond. B

171

142

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This article sets out to present a fairly comprehensive review of our knowledge about the functions of the receptors that have been found in the extraocular muscles--the six muscles that move each eye of vertebrates in its orbit--of all the animals in which they have been sought, including Man. Since their discovery at the beginning of the 20th century these receptors have, at various times, been credited with important roles in the control of eye movement and the construction of extrapersonal space and have also been denied any function whatsoever. Experiments intended to study the actions of eye muscle receptors and, even more so, opinions (and indeed polemic) derived from these observations have been influenced by the changing fashions and beliefs about the more general question of how limb position and movement is detected by the brain and which signals contribute to those aspects of this that are perceived (kinaesthesis). But the conclusions drawn from studies on the eye have also influenced beliefs about the mechanisms of kinaesthesis and, arguably, this influence has been even larger than that in the converse direction. Experimental evidence accumulated over rather more than a century is set out and discussed. It supports the view that, at the beginning of the 21st century, there are excellent grounds for believing that the receptors in the extraocular muscles are indeed proprioceptors, that is to say that the signals that they send into the brain are used to provide information about the position and movement of the eye in the orbit. It seems that this information is important in the control of eye movements of at least some types, and in the determination by the brain of the direction of gaze and the relationship of the organism to its environment. In addition, signals from these receptors in the eye muscles are seen to be necessary for the development of normal mechanisms of visual analysis in the mammalian visual cortex and for both the development and maintenance of normal visuomotor behaviour. Man is among those vertebrates to whose brains eye muscle proprioceptive signals provide information apparently used in normal sensorimotor functions; these include various aspects of perception, and of the control of eye movement. It is possible that abnormalities of the eye muscle proprioceptors and their signals may play a part in the genesis of some types of human squint (strabismus); conversely studies of patients with squint in the course of their surgical or pharmacological treatment have yielded much interesting evidence about the central actions of the proprioceptive signals from the extraocular muscles. The results of experiments on the eye have played a large part in the historical controversy, now in at least its third century, about the origin of signals that inform the brain about movement of parts of the body. Some of these results, and more of the interpretations of them, now need to be critically re-examined. The re-examination in the light of recent experiments that is presented here does not ...

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Section: (Iv) Pigeonsupporting

confidence: 64%

Section: (D) Other Endingsmentioning

confidence: 97%

Section: Why Do Some Animals Have Muscle Spindles In Their Extraoculamentioning

confidence: 99%

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The functions of the proprioceptors of the eye muscles

Donaldson

2000

Phil. Trans. R. Soc. Lond. B

171

142

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“…Our study carried out in the African black ostrich, from the 28 th day of incubation until 3 years of age, assessed all the EOMs and revealed that the muscle fibres were larger and the perimysium increased in thickness in groups II to V. An external capsule was Acta Biologica Hungarica 69, 2018 visible in group III, while transverse striation was noted from the groups II to V. The number, diameter and length of the muscle fibres as well as the diameter of the fascicles grew linearly with age in all the age groups. Similarly to the study of Maier et al [22], we found an absence of muscle spindles in the EOMs. The confirmation or contradiction of the presence of muscle spindles in these birds requires immunohistochemical and ultrastructural examinations.…”

Section: Discussionsupporting

confidence: 90%

Morphology of the extraocular muscles (m. bulbi) in the pre-hatchling and post-hatchling african black ostriches (struthio camelus domesticus L., 1758) (Aves: Struthioniformes)

Klećkowska‐Nawrot

Goździewska‐Harłajczuk

Barszcz

et al. 2018

Acta Biologica Hungarica

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The aim of the study was to describe the morphology and the development of the extraocular muscles (EOMs) in the pre-hatchling and post-hatchling African black ostrich. The study involved 50 birds aged between 28 days and 3 years. The EOMs were analyzed morphologically with respect to the location and length of the straight and oblique muscles and the third eyelid muscles, the length and breadth of their tendons as well as the distance and shape of the muscle tendon insertions at the corneal limbus. A histological and histometric analysis were also carried out. The greatest increase in the length of the EOMs was noted in groups III-V. A marked increase in the length of the tendons of the dorsal straight muscle was found in groups II and III, in the tendons of the nasal straight muscle in groups IV and V, in the tendons of the dorsal oblique muscle in groups III to V and in the tendons of the ventral oblique muscle in groups IV and V. There was a significant increase in the breadth of the dorsal straight and ventral oblique muscle tendons in groups IV and V and the tendons of the pyramidal muscle in groups III and V. The distance of the distal insertion of the tendon at the corneal limbus increased steadily with age in all the examined groups. The number of fascicles and muscle fibres, their diameter and length in all the studied EOMs were different in the different groups.

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“…In the cat, MesV cells are labeled after eye muscle injections (Alvarado-Mallart et al, 1975). In several avian species including the duck, however, spindles are lacking in extraocular muscles (Azzena et al, 1970;Maier et al, 1971).…”

Section: Discussionmentioning

confidence: 99%

Central connections of the nucleus mesencephalicus nervi trigemini in the mallard (Anas platyrhynchosL.).

1997

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Background In the mallard duck, functionally distinct groups of jaw muscles are each innervated by a different subnucleus of the main trigeminal (mV) or facial (mVII) motor nucleus. The other subnuclei of mV and mVII innervate several head muscles, including lingual muscles. The reticular premotor cells of the trigeminal and facial jaw motor subnuclei occupy different areas in the parvocellular reticular formation (RPc). The cell bodies of jaw muscle spindle afferents are situated in the mesencephalic nucleus (MesV). In the present study, the central connections of MesV with jaw motor subnuclei and their premotor areas are investigated. Methods In a first series of experiments, horseradish peroxidase (HRP) injections were made in electrophysiologically identified trigeminal and facial subnuclei. In a second series of experiments, HRP was delivered iontophoretically at different parts of RPc. Anterograde tracing with tritiated leucine was used to confirm the central connections of MesV. Double labeling with fluorescent tracers was used to investigate whether MesV collaterals reach both the rostral and caudal parts of RPc. Results MesV projects to only two of the five different subnuclei of the trigeminal motor nucleus. The subnuclei that receive spindle afferents innervate jaw adductor muscles (mV2) or pro‐ and retractors of the mandible (pterygoid muscles; mV1). The three other subnuclei innervate jaw‐opener muscles or other head muscles. MesV fibers also project to the rostral part of the dorsolateral RPc (RPcdl), which serves as a premotor area for the motor subnuclei of adductor and pterygoid muscles. The intermediate part of RPcdl does not contain premotor cells of mV or mVII, and a clear projection of MesV to this area is absent. The caudal part of RPcdl projects to the mV and mVII subnuclei that innervate jaw‐opener muscles. This part of RPc receives a projection from the same MesV cells as the rostral RPcdl. The MesV projection to RPc does not include premotor cells of mV and mVII in the ventromedial part of RPc (RPcvm). Conclusions Spindle afferents from jaw‐closer muscles project only to mV subnuclei innervating jaw‐closer muscles (mV1, mV2) and to a population of premotor cells in the rostral RPcdl that innervates these subnuclei. The mixed population of premotor cells in RPcvm, which innervates both jaw‐opener and jaw‐closer subnuclei, does not receive a MesV projection. However, a premotor area for jaw‐opener subnuclei in the caudal part of RPcdl does receive MesV input and may serve as a relay through which proprioceptive information from jaw closer spindles can reach jaw opener muscles. Anat. Rec. 248:554‐565, 1997. © 1997 Wiley‐Liss, Inc.

show abstract

Absence of muscle spindles in avian extraocular muscles

Cited by 14 publications

References 8 publications

The functions of the proprioceptors of the eye muscles

The functions of the proprioceptors of the eye muscles

Morphology of the extraocular muscles (m. bulbi) in the pre-hatchling and post-hatchling african black ostriches (struthio camelus domesticus L., 1758) (Aves: Struthioniformes)

Central connections of the nucleus mesencephalicus nervi trigemini in the mallard (Anas platyrhynchosL.).

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