GABAergic innervation of the ciliary ganglion in macaque monkeys - A light and electron microscopic study.

The vertebrate ciliary ganglion (CG) is a relay station in the parasympathetic pathway activating the iris sphincter and ciliary muscle to mediate pupillary constriction and lens accommodation, respectively. While the postganglionic motoneurons in the CG are cholinergic, as are their inputs, there is evidence from avian studies that GABA may also be involved. Here, we used light and electron microscopic methods to examine the GABAergic innervation of the CG in Macaca fascicularis monkeys.

Palisade Endings Are a Constant Feature in the Extraocular Muscles of Frontal-Eyed, But Not Lateral-Eyed, Animals.

Purpose: To test whether palisade endings are a general feature of mammalian extraocular muscles (EOMs).

Methods: Thirteen species, some frontal-eyed (human, monkey, cat, and ferret), and others lateral-eyed (pig, sheep, calf, horse, rabbit, rat, mouse, gerbil, and guinea pig) were analyzed. Palisade endings were labeled by using different combinations of immunofluorescence techniques.

Calretinin as a Marker for Premotor Neurons Involved in Upgaze in Human Brainstem.

Eye movements are generated by different premotor pathways. Damage to them can cause specific deficits of eye movements, such as saccades. For correlative clinico-anatomical post-mortem studies of cases with eye movement disorders it is essential to identify the functional cell groups of the oculomotor system in the human brain by marker proteins.

A central mesencephalic reticular formation projection to the Edinger-Westphal nuclei.

The central mesencephalic reticular formation, a region associated with horizontal gaze control, has recently been shown to project to the supraoculomotor area in primates. The Edinger-Westphal nucleus is found within the supraoculomotor area. It has two functionally and anatomically distinct divisions: (1) the preganglionic division, which contains motoneurons that control both the actions of the ciliary muscle, which focuses the lens, and the sphincter pupillae muscle, which constricts the iris, and (2) the centrally projecting division, which contains peptidergic neurons that play a role in food and fluid intake, and in stress responses.

Transmitter inputs to different motoneuron subgroups in the oculomotor and trochlear nucleus in monkey.

In all vertebrates the eyes are moved by six pairs of extraocular muscles enabling horizontal, vertical and rotatory movements. Recent work showed that each extraocular muscle is controlled by two motoneuronal groups: (1) Motoneurons of singly-innervated muscle fibers (SIF) that lie within the boundaries of motonuclei mediating a fast muscle contraction; and (2) motoneurons of multiply-innervated muscle fibers (MIF) in the periphery of motonuclei mediating a tonic muscle contraction. Currently only limited data about the transmitter inputs to the SIF and MIF motoneurons are available.

Saccadic Palsy following Cardiac Surgery: Possible Role of Perineuronal Nets.

Objective: Perineuronal nets (PN) form a specialized extracellular matrix around certain highly active neurons within the central nervous system and may help to stabilize synaptic contacts, promote local ion homeostasis, or play a protective role. Within the ocular motor system, excitatory burst neurons and omnipause neurons are highly active cells that generate rapid eye movements - saccades; both groups of neurons contain the calcium-binding protein parvalbumin and are ensheathed by PN. Experimental lesions of excitatory burst neurons and omnipause neurons cause slowing or complete loss of saccades.

Saccadic palsy following cardiac surgery: a review and new hypothesis.

The ocular motor system provides several advantages for studying the brain, including well-defined populations of neurons that contribute to specific eye movements. Generation of rapid eye movements (saccades) depends on excitatory burst neurons (EBN) and omnipause neurons (OPN) within the brainstem, both types of cells are highly active. Experimental lesions of EBN and OPN cause slowing or complete loss of saccades.

Internal organization of medial rectus and inferior rectus muscle neurons in the C group of the oculomotor nucleus in monkey.

Mammalian extraocular muscles contain singly innervated twitch muscle fibers (SIF) and multiply innervated nontwitch muscle fibers (MIF). In monkey, MIF motoneurons lie around the periphery of oculomotor nuclei and have premotor inputs different from those of the motoneurons inside the nuclei. The most prominent MIF motoneuron group is the C group, which innervates the medial rectus (MR) and inferior rectus (IR) muscle.

Delineation of motoneuron subgroups supplying individual eye muscles in the human oculomotor nucleus.

The oculomotor nucleus (nIII) contains the motoneurons of medial, inferior, and superior recti (MR, IR, and SR), inferior oblique (IO), and levator palpebrae (LP) muscles. The delineation of motoneuron subgroups for each muscle is well-known in monkey, but not in human. We studied the transmitter inputs to human nIII and the trochlear nucleus (nIV), which innervates the superior oblique muscle (SO), to outline individual motoneuron subgroups.

Characterization of neuronal populations in the human trigeminal ganglion and their association with latent herpes simplex virus-1 infection.

Following primary infection Herpes simplex virus-1 (HSV-1) establishes lifelong latency in the neurons of human sensory ganglia. Upon reactivation HSV-1 can cause neurological diseases such as facial palsy, vestibular neuritis or encephalitis. Certain populations of sensory neurons have been shown to be more susceptible to latent infection in the animal model, but this has not been addressed in human tissue.

Calretinin inputs are confined to motoneurons for upward eye movements in monkey.

Motoneurons of extraocular muscles are controlled by different premotor pathways, whose selective damage may cause directionally selective eye movement disorders. The fact that clinical disorders can affect only one direction, e.g.

Palisade endings and proprioception in extraocular muscles: a comparison with skeletal muscles.

This article describes current views on motor and sensory control of extraocular muscles (EOMs) based on anatomical data. The special morphology of EOMs, including their motor innervation, is described in comparison to classical skeletal limb and trunk muscles. The presence of proprioceptive organs is reviewed with emphasis on the palisade endings (PEs), which are unique to EOMs, but the function of which is still debated.

Immunohistochemical detection of intra-neuronal VZV proteins in snap-frozen human ganglia is confounded by antibodies directed against blood group A1-associated antigens.

Varicella-zoster virus (VZV) causes chickenpox, establishes latency in trigeminal (TG) and dorsal root ganglia (DRG), and can lead to herpes zoster upon reactivation. The VZV proteome expressed during latency remains ill-defined, and previous studies have shown discordant data on the spectrum and expression pattern of VZV proteins and transcripts in latently infected human ganglia. Recently, Zerboni and colleagues have provided new insight into this discrepancy (Zerboni et al.

Sources of calretinin inputs to motoneurons of extraocular muscles involved in upgaze.

Recent monkey studies showed that motoneurons of the oculomotor nucleus involved in upward eye movements receive a selective input from afferents containing calretinin (CR). Here, we investigated the sources of these CR-positive afferents. After injections of tract-tracers into the oculomotor nucleus (nIII) of two monkeys, the retrograde labeling was combined with CR-immunofluorescence in frozen brainstem sections.

Is there any sense in the Palisade endings of eye muscles?

Palisade endings (PEs), which are unique to the eye muscles, are associated with multiply innervated muscle fibers. They lie at the myotendinous junctions and form a cap around the muscle fiber tip. They are found in all animals investigated so far, but their function is not known.

The anatomy and physiology of the ocular motor system.

Accurate diagnosis of abnormal eye movements depends upon knowledge of the purpose, properties, and neural substrate of distinct functional classes of eye movement. Here, we summarize current concepts of the anatomy of eye movement control. Our approach is bottom-up, starting with the extraocular muscles and their innervation by the cranial nerves.

The Edinger-Westphal nucleus: a historical, structural, and functional perspective on a dichotomous terminology.

The eponymous term nucleus of Edinger-Westphal (EW) has come to be used to describe two juxtaposed and somewhat intermingled cell groups of the midbrain that differ dramatically in their connectivity and neurochemistry. On one hand, the classically defined EW is the part of the oculomotor complex that is the source of the parasympathetic preganglionic motoneuron input to the ciliary ganglion (CG), through which it controls pupil constriction and lens accommodation. On the other hand, EW is applied to a population of centrally projecting neurons involved in sympathetic, consumptive, and stress-related functions.

Do palisade endings in extraocular muscles arise from neurons in the motor nuclei?

Purpose: The purpose of this study was to localize the cell bodies of palisade endings that are associated with the myotendinous junctions of the extraocular muscles.

Methods: Rhesus monkeys received tract-tracer injections (tetramethylrhodamine dextran [TMR-DA] or choleratoxin subunit B [CTB]) into the oculomotor and trochlear nuclei, which contain the motoneurons of extraocular muscles. All extraocular muscles were processed for the combined immunocytochemical detection of the tracer and SNAP-25 or synaptophysin for the visualization of the complete muscle innervation.

The Edinger-Westphal nucleus represents different functional cell groups in different species.

In all vertebrates, including humans, the Edinger-Westphal nucleus (EW) forms a circumscribed cell group dorsomedial to the oculomotor nucleus (nIII). Traditionally the EW is considered the location of parasympathetic preganglionic neurons of the ciliary ganglion, mediating pupillary constriction and accommodation. In a comparative study in rat, ferret, monkey, and human, the location of cholinergic neurons within and around the nIII, which includes motoneurons of the extra-ocular muscles and the preganglionic neurons of the ciliary ganglion, was compared to the location of urocortin-positive neurons.

Selective, circuit-wide sparing of floccular connections in hereditary olivopontine cerebellar atrophy with slow saccades.

We present a systems-oriented histopathologic analysis of the ocular motor control circuits in the cerebellum and brainstem from a patient with a hereditary form of olivopontine cerebellar atrophy of the Wadia type, which has a characteristic ocular motor presentation of slow saccades but relative preservation of smooth pursuit and gaze-holding. This differential pattern of clinical involvement is associated with a lobule-specific pattern of cerebellar degeneration. We asked whether these patterns of sparing and degeneration were consistent throughout the associated deep cerebellar and brainstem structures.

Brainstem circuits controlling lid-eye coordination in monkey.

In primate, the M-group is a cell cluster in the rostral mesencephalon which contains premotor neurons for the levator palpebrae (LP) and upward-pulling eye muscles. It is therefore thought to play a role in lid-eye coupling during vertical saccades. To further elucidate its role, the afferents to the M-group and LP motoneurons were studied in monkeys.

Neuronal signalling expression profiles of motoneurons supplying multiply or singly innervated extraocular muscle fibres in monkey.

Motoneurons of the oculomotor nucleus subserving multiply innervated muscle fibres (MIF) receive different afferent inputs from the motoneurons subserving singly innervated muscle fibres (SIF). We asked whether MIF and SIF motoneurons have different neurotransmitter signalling expression profiles. Adult rhesus monkey extraocular muscles were injected with the retrograde tracer cholera toxin.

Perioculomotor cell groups in monkey and man defined by their histochemical and functional properties: reappraisal of the Edinger-Westphal nucleus.

The perioculomotor region contains several functional cell groups, including parasympathetic preganglionic neurons of the ciliary ganglion, motoneurons of multiply innervated muscle fibers (MIF) of extraocular muscles, and urocortin-positive neurons. In this study, midbrain sections of monkey and human were treated with antibodies against choline acetyltransferase (ChAT), cytochrome oxidase (CytOx), nonphosphorylated neurofilaments (NP-NF), chondroitin sulfate proteoglycan (CSPG), and urocortin (UCN) to identify them by their histochemical properties. To facilitate the comparison between species, a new nomenclature was introduced (see also May et al.

Nucleus prepositus.

The cytoarchitecture and the histochemistry of nucleus prepositus hypoglossi and its afferent and efferent connections to oculomotor structures are described. The functional significance of the afferent connections of the nucleus is discussed in terms of current knowledge of the firing behavior of prepositus neurons in alert animals. The efferent connections of the nucleus and the results of lesion experiments suggest that it plays a role in a variety of functions related to the control of gaze.

The reticular formation.

The reticular formation of the brainstem contains functional cell groups that are important for the control of eye, head, or lid movements. The mesencephalic reticular formation is primarily involved in the control of vertical gaze, the paramedian pontine reticular formation in horizontal gaze, and the medullary pontine reticular formation in head movements and gaze holding. In this chapter, the locations, connections, and histochemical properties of the functional cell groups are reviewed and correlated with specific subdivisions of the reticular formation.