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'Extraocular Muscles Actions' (62)


Dec
2017

Comparison of three models of saccade disconjugacy in strabismus.

J Neurophysiol 2017 Dec 13;118(6):3175-3193. Epub 2017 Sep 13.
Mark M G Walton, Michael J Mustari
In pattern strabismus the horizontal and vertical misalignments vary with eye position along the orthogonal axis. The disorder is typically described in terms of overaction or underaction of oblique muscles. Recent behavioral studies in humans and monkeys, however, have reported that such actions are insufficient to fully explain the patterns of directional and amplitude disconjugacy of saccades.

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Jun
2016

Upper eyelid movement depends on the antagonistic actions of orbicularis oculi muscle and levator aponeurosis. Blepharoptosis is an abnormal drooping of upper eyelid margin with the eye in primary position of gaze. Transconjunctival incisions for upper eyelid ptosis correction have been a well-developed technique.

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Jan
2016

Anatomical studies demonstrate selective compartmental innervation of most human extraocular muscles (EOMs), suggesting the potential for differential compartmental control. This was supported by magnetic resonance imaging (MRI) demonstrating differential lateral rectus (LR) compartmental contraction during ocular counterrolling, differential medial rectus (MR) compartmental contraction during asymmetric convergence, and differential LR, inferior rectus (IR), and superior oblique (SO) compartmental contraction during vertical vergence. To ascertain possible differential compartmental EOM contraction during vertical ductions, surface coil MRI was performed over a range of target-controlled vertical gaze positions in 25 orbits of 13 normal volunteers.

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Apr
2015

Vertical fusional vergence (VFV) normally compensates for slight vertical heterophorias. We employed magnetic resonance imaging to clarify extraocular muscle contributions to VFV induced by monocular two-prism diopter (1.15°) base-up prism in 14 normal adults.

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Dec
1969

Developmental and evolutionary data from vertebrates are beginning to elucidate the origin of the sensorimotor pathway that links gravity and motion detection to image-stabilizing eye movements--the vestibulo-ocular reflex (VOR). Conserved transcription factors coordinate the development of the vertebrate ear into three functional sensory compartments (graviception/translational linear acceleration, angular acceleration and sound perception). These sensory components connect to specific populations of vestibular and auditory projection neurons in the dorsal hindbrain through undetermined molecular mechanisms.

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Oct
2013

Past rewards capture spatial attention and action choices.

Exp Brain Res 2013 Oct 14;230(3):291-300. Epub 2013 Aug 14.
E Camara, S Manohar, M Husain
The desire to increase rewards and minimize punishing events is a powerful driver in behaviour. Here, we assess how the value of a location affects subsequent deployment of goal-directed attention as well as involuntary capture of attention on a trial-to-trial basis. By tracking eye position, we investigated whether the ability of an irrelevant, salient visual stimulus to capture gaze (stimulus-driven attention) is modulated by that location's previous value.

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Aug
2013

To determine whether surgery to correct decompensated exotropia in adulthood had an impact on common visually guided manual tasks in the postoperative period.
Case report.
Three adult patients with long-standing strabismus.

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Aug
2013

Horizontal eye movements are conducted by the medial rectus and the lateral rectus muscles, which are innervated by the oculomotor nerve (cranial nerve III) and the abducens nerve (cranial nerve VI), respectively. The oculomotor and the abducens nuclei are interconnected by a tract in the brainstem named the medial longitudinal fasciculus (MLF). Through the MLF, the actions of the oculomotor and the abducens nuclei are coordinated, generating conjugate horizontal eye movements.

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Dec
2012

Intramuscular innervation of horizontal rectus extraocular muscles (EOMs) is segregated into superior and inferior (transverse) compartments, while all EOMs are also divided into global (GL) and orbital (OL) layers with scleral and pulley insertions, respectively. We sought evidence of potential independent action by examining passive mechanical coupling between EOM compartments.
Putative compartments of each of the six whole bovine anatomical EOMs were separately clamped to a physiologically controlled, dual channel microtensile load cell (5-mN force resolution) driven by independent, high-speed, linear motors having 20-nm position resolution.

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Dec
1969

A major challenge in computational neurobiology is to understand how populations of noisy, broadly-tuned neurons produce accurate goal-directed actions such as saccades. Saccades are high-velocity eye movements that have stereotyped, nonlinear kinematics; their duration increases with amplitude, while peak eye-velocity saturates for large saccades. Recent theories suggest that these characteristics reflect a deliberate strategy that optimizes a speed-accuracy tradeoff in the presence of signal-dependent noise in the neural control signals.

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Jun
2012

To elucidate the aetiology of congenital Brown syndrome.
Four consecutive patients diagnosed with unilateral congenital Brown syndrome had a comprehensive standardized ocular motility examination. Any compensatory head posture was measured.

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May
2011

Humans tend to create and maintain internal representations of the environment that help guiding actions during the everyday activities. Previous studies have shown that the oculomotor system is involved in coding and maintenance of locations in visual-spatial working memory. In these studies selection of the relevant location for maintenance in working memory took place on the screen (selecting the location of a dot presented on the screen).

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Dec
1969

[Orbital decompression in Grave's ophtalmopathy].

Rev Laryngol Otol Rhinol (Bord) 2010 ;131(2):145-52
E Longueville
Graves disease orbitopathy is a complex progressive inflammatory disease. Medical treatment remains in all cases the proposed treatment of choice. Surgical treatment by bone decompression can be considered as an emergency mainly in cases of optic neuropathy or ocular hypertension not being controlled medically or in post-traumatic exophthalmos stage.

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Jun
2011

Uniocular and binocular fields of rotation measures: Octopus versus Goldmann.

Graefes Arch Clin Exp Ophthalmol 2011 Jun 18;249(6):909-19. Epub 2011 Jan 18.
Fiona J Rowe, Sahira Hanif
To compare the range of ocular rotations measured by Octopus versus Goldmann perimetry.
Forty subjects (20 controls and 20 patients with impaired ocular movements) were prospectively recruited, age range 21-83 years. Range of uniocular rotations was measured in six vectors corresponding to extraocular muscle actions: 0°, 67°, 141°, 180°, 216°, 293°.

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Apr
2011

It has been proposed that the lateral rectus (LR), like many skeletal and craniofacial muscles, comprises multiple neuromuscular compartments subserving different physiological functions. To explore the anatomic potential of compartmentalization in all four rectus extraocular muscles (EOMs), evidence was sought of possible regional selectivity in intramuscular innervation of all rectus EOMs.
Whole orbits of two humans and one macaque monkey were serially sectioned at 10 μm thickness and stained with Masson's trichrome.

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Sep
2010

Skeletal and craniofacial muscles are frequently composed of multiple neuromuscular compartments that serve different physiological functions. Evidence of possible regional selectivity in LR intramuscular innervation was sought in a study of the anatomic potential of lateral rectus (LR) muscle compartmentalization.
Whole orbits of two humans and five macaque monkeys were serially sectioned at 10-microm thickness and stained with Masson trichrome.

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Apr
2010

The spatial arrangement of the semicircular canals and extraocular muscles of the eye has been of considerable interest, particularly to researchers working on adaptations of the vestibulo-ocular reflex. Here we offer the first, extensive comparative analysis of the spatial relationships between each extraocular muscle and the canal providing its primary excitatory stimulus. The sample consisted of 113 specimens, representing 51 extant mammalian species.

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Nov
2009

Urocortin 1 (Ucn 1) is an endogenous peptide related to the corticotropin-releasing factor (CRF). Ucn 1 is mainly expressed in the perioculomotor area (pIII), and its involvement in alcohol self-administration is well confirmed in mice. In other species, the relationship between the perioculomotor Ucn 1-containing population of neurons (pIIIu) and alcohol consumption needs further investigation.

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Dec
1969

A great demand for brain-machine and, more generally, man-machine interfaces is arising nowadays, pushed by several promising scientific and technological results, which are encouraging the concentration of efforts in this field. The possibility of measuring, processing and decoding brain activity, so as to interpret neural signals, is often looked at as a possibility to bypass lost or damaged neural and/or motor structures. Beyond that, such interfaces currently show a potential for applications in other fields, space science being certainly one of them.

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Feb
2009

In subjects trained extensively to indicate a perceptual decision with an action, neural commands that generate the action can represent the process of forming the decision. However, it is unknown whether this representation requires overtraining or reflects a more general link between perceptual and motor processing. We examined how perceptual processing is represented in motor commands in naive monkeys being trained on a demanding perceptual task, as they first establish the sensory-motor association and then learn to form more accurate perceptual judgments.

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Feb
2009

The actions of the individual extraocular muscles are best explained to medical students in a lecture format by showing the relationship of each muscle to the axes of the globe and the walls of the bony orbit. The lateral and medial rectus muscles cross only the vertical axis, and consequently, cause only abduction and adduction, respectively. These muscles can be tested simply by asking the patient to abduct or adduct.

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Dec
2007

Ocular misalignment and ophthalmoparesis result in the symptom of binocular diplopia. In the evaluation of diplopia, localization of the ocular motility disorder is the main objective. This requires a systematic approach and knowledge of the ocular motor pathways and actions of the extraocular muscles.

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Jul
2007

Oculomotor disorders.

Semin Neurol 2007 Jul;27(3):244-56
Janet C Rucker
Ocular misalignment and nystagmus result in the visual symptoms of binocular diplopia and oscillopsia, and are frequently encountered in neurological practice. Correct localization of the underlying problem is the first step to accurate diagnosis, and requires a systematic approach and knowledge of the ocular motor pathways and actions of the extraocular muscles. This article contains three segments: The first outlines the diagnostic approach with attention to fine historical and examination details helpful in localization; the second describes common localizations of diplopia including extraocular muscle, neuromuscular junction, cranial nerve and nuclei, and supranuclear structures with attention to examination features characteristic for each location; and the third describes the types of acquired nystagmus and their treatments.

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Dec
1969

The principles of surgery of the oblique muscles are different from those of the rectus muscles according to their anatomy and physiology. Their exposure is difficult as they are inserted on the sclera behind the equator and because they form an angle of 51s with the visual axis they have a triple action. The types of procedures one can practice on the oblique muscles are: weakening and strengthening of their actions.

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Jan
2006

Magnetic resonance imaging (MRI) was used to determine the effect of recessions and resections on horizontal extraocular muscle (EOM) paths and globe position.
Four adults with horizontal strabismus underwent contrast-enhanced, surface-coil MRI in central, secondary, and tertiary gazes, before and after horizontal EOM recessions and/or resections. EOM paths were determined from 2-mm thickness, quasicoronal MRI by analysis of cross-sectional area centroids in a normalized, oculocentric coordinate system.

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Sep
2005

The question whether general tetanus arises from the independent sum of multiple local tetani or results from the actions of the transynaptic tetanus neurotoxin (TeNT) in higher brain centres remains unresolved. Despite the blood-borne dissemination of TeNT from an infected wound, the access to the central nervous system is probably prevented by the blood-brain barrier. However, several long-term sequelae (e.

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Dec
2003

A fundamental question in primate neurobiology is to understand to what extent motor behaviors are driven by shared neural signals that also support conscious perception or by independent subconscious neural signals dedicated to motor control. Although it has clearly been established that cortical areas involved in processing visual motion support both perception and smooth pursuit eye movements, it remains unknown whether the same or different sets of neurons within these structures perform these two functions. Examination of the trial-by-trial variation in human perceptual and pursuit responses during a simultaneous psychophysical and oculomotor task reveals that the direction signals for pursuit and perception are not only similar on average but also co-vary on a trial-by-trial basis, even when performance is at or near chance and the decisions are determined largely by neural noise.

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Apr
2004

Early compensatory mechanisms between eyelid and eye-retraction motor systems following selective nerve and/or muscle lesions were studied in behaving rabbits. Reflex and conditioned eyelid responses were recorded in 1). controls and following 2).

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Jul
2002

Connective tissue pulleys serve as functional mechanical origins of the extraocular muscles (EOMs) and are normally stable relative to the orbit during gaze shifts. This study evaluated pulley stability in incomitant strabismus.
Contiguous 2- or 3-mm thick magnetic resonance images (MRIs) perpendicular to the orbital axis spanned the anteroposterior extents of 12 orbits of six patients with incomitant strabismus.

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Mar
2001

Diplopia caused by local anesthesia at the superior posterior alveolar nerve for the removal of the maxillary third molar is a rare complication. The diplopia is due to facial palsy of the oculomotor muscles of the globe. This paper describes the case of a 22-year-old woman, in whom diplopia was observed after an overall uncomplicated removal of the semi-impacted third molar.

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Apr
2002

Complex learned motor sequences can be composed of a combination of a small number of elementary actions. To investigate how the brain represents such sequences, we devised an oculomotor sequence task in which the monkey had to choose the target solely by the sequential context, not by the current stimulus combination. We found that many neurons in the supplementary eye field (SEF) became active with a specific target direction (D neuron) or a specific target/distractor combination (C neuron).

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Dec
1969

To obtain objective information about the effects of different amounts and directions of superior oblique muscle (SO) recession, on its three force components: torsional (incyclotorsion), vertical (depression), and horizontal (abduction).
A well known Biomechanical Model of Ocular Motility (Orbit 1.8 Gaze Mechanics Simulation), was used to simulate different amounts of recession of the superior oblique muscle, along three different and commonly used axes of recession: a) along its anatomical path (the hypothetical line uniting the trochlea and the scleral insertion of the SO); b) anteroposteriorly on the nasal side of the superior rectus muscle (recession with posterior transposition); and c) straightforward nasal transposition around the globe.

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Aug
2001

Two experiments were conducted in order to determine the patterns of transfer of visuomotor adaptation between arm and head pointing. An altered gain of display of pointing movements was used to induce a conflict between visual and somatosensory representations. Two subject groups participated in Experiment 1: group 1 adapted shoulder pointing movements, and group 2 adapted wrist pointing movements to a 0.

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Apr
2001

We previously reported an 8% incidence of double-bellied inferior oblique (IO) muscles at the surgical capture site (10-12 mm from insertion) in cadaveric specimens. This companion study sought to determine how often this anomaly is encountered at surgery for clinically overacting IO muscles and whether clinical findings or surgical outcomes in cases with double-bellied muscles differ from those with single-bellied muscles.
For 7 years we collected preoperative, intraoperative, and postoperative data on all patients for whom one surgeon performed primary IO weakening operations for overactions.

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Dec
2000

The functions of the proprioceptors of the eye muscles.

Philos Trans R Soc Lond B Biol Sci 2000 Dec;355(1404):1685-754
I M Donaldson
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).

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Nov
2000

To evaluate the reliability of strabismus assessment using telemedicine (TM) technology.
Two prospective interobserver agreement studies. One study compared the agreement between a standard and a TM examination, whereas the other assessed agreement between two independent standard examinations.

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Aug
1997

Movements of the head and eyes are known to be intimately related. Eye position has also been shown to be closely related to the electromyographic activity of dorsal neck muscles; however, extraocular muscle proprioception has not generally been considered to play a part in the control of such movements. We have previously shown that, in the pigeon, imposed movements of one eye modify the vestibular responses of several dorsal neck muscles in ways that are dependent on stimulus parameters such as the amplitude and velocity of imposed eye movement.

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Aug
1997

Surgical implications of the rectus extraocular muscle pulleys.

J Pediatr Ophthalmol Strabismus 1996 Jul-Aug;33(4):208-18
J L Demer, J M Miller, V Poukens
Magnetic resonance imaging (MRI) shows that the paths of rectus extraocular muscle bellies remain fixed in the orbit during large ocular rotations, and across large surgical transpositions of their insertions. This stability of muscle paths is due to their passage through pulleys which are coupled to the orbit and located in a coronal plane anterior to the muscle bellies near the equator of the globe. Autopsy studies have shown the pulleys to be fibroelastic sleeves consisting of dense bands of collagen and elastin, suspended from the orbit and adjacent extraocular muscle sleeves by bands of similar composition.

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Nov
1995

Recent physiological experiments in our laboratory suggest that extraocular muscle proprioceptive signals are involved in oculomotor control in the pigeon [e.g., Knox and Donaldson (1993) Proc.

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Jul
1994

Vertical saccadic movements recorded with electrooculography (EOG) and force development measured by means of a contact lens-strain gauge technique were investigated in 13 patients with a clinical diagnosis of unilateral superior oblique palsy (SOP) and 10 normal subjects. Upward and downward movements from the horizontal level to 5, 10 and 20 deg of deviation with monocular fixation were made in the 20 deg abduction and adduction fields of gaze. Peak velocity (Vp) and the ratio of downward over upward movement (VpD/U) of the paretic eye (PE) and the sound eye (SE) of the patients were compared with the values of the covered, non-fixating eye (CE) and the fixating eye (FE) of the normals respectively.

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Aug
1993

The neurobiology of primate vision.

Baillieres Clin Neurol 1993 Aug;2(2):191-225
R J Douglas, K A Martin, J C Nelson
Studies of the visual system of the primate have taken two directions. One group of neurobiologists have studied the oculomotor system, while an entirely separate group have analysed sensory processing in the retinogeniculo-cortical circuits. However, the versatility and adaptability of the primate visual system is only possible because sensory and oculomotor processing are highly integrated.

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Aug
1993

Vertical diplopia.

Surv Ophthalmol 1993 Jul-Aug;38(1):31-62
R H Spector
An accurate clinical evaluation of vertical diplopia is predicated upon meticulous history-taking, observations regarding the presence and pattern of an anomalous head position, and the analysis of several subjective and objective tests of extraocular muscle function. To reach a final diagnosis with minimum risk and expense to the patient the examiner must be familiar with the neuroanatomy of the supranuclear and infranuclear pathways which control the actions of the vertically-acting extraocular muscles, the clinical methods and pitfalls of a number of clinical techniques which are used to identify an underacting extraocular muscle, and the hallmark characteristics of a supranuclear, infranuclear and restrictive ophthalmopathy.

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Apr
1990

[Vertical and tortional deviations in early strabismus].

Bull Soc Ophtalmol Fr 1990 Apr;90(4):373-8, 381-4
A Spielmann
The occlusion of one eye may trigger two types of deviation: 1) Heterophorias: the occluded eye deviates towards a horizontal, vertical or torsional abnormal position of rest. Fusion keeps the eyes straight during binocular fixation. 2) Dissociated deviations, horizontal (DHD), vertical (DVD), torsional (DTD): they are found in infantile strabismus.

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Dec
1969

The actions of extraocular muscles depend on their positions as a function of gaze. These positions vary with muscle forces, which are normal only in alert subjects making voluntary fixations. Magnetic Resonance Imaging (MRI) was used to view normal human orbits, with voluntary gaze varied over a circular field 77 deg in dia, centered on the orbital axis.

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Dec
1969

Contrasting views on the actions of the extraocular muscles are discussed. The contributions made by clinicians are compared to those made by investigators with a background in physical science. It is shown that a clear understanding of the mechanics of the extraocular muscles can be used to increase the efficiency of oculomotility tests.

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May
1984

Superior oblique muscle surgery.

Aust J Ophthalmol 1984 May;12(2):167-9
B Harcourt
The anatomy and actions of the superior oblique muscle are discussed as a basis for logical surgical procedures. Weakening procedures are indicated for overaction or for a short superior oblique tendon. Tenectomy is performed nasal to the superior rectus while selective tenotomies for bilateral overaction are performed temporal to the superior rectus.

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Apr
1983

The electric organs of Astroscopus are modified from extraocular muscles and innervated by the enlarged oculomotor nuclei. The electromotor neuron somata are contacted by fine processes with which they form gap junctions. Presynaptic vesicles and active zones are also present, although physiological data give no indication of chemically mediated transmission.

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Dec
1969

The vestibulo-ocular reflex rotates the eye about the axis of a head rotation at the same speed but in the opposite direction to make the visual axes in space independent of head motion. This reflex works in all three degrees of freedom: roll, pitch, and yaw. The rotations may be described by vectors and the reflex by a transformation in the form of a matrix.

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Feb
1981

The functions of cells in different parts of area 7 were studied in 5 hemispheres of three stumptail macaques (Macaca speciosa). Activity of groups of cells was recorded in non-anesthetized animals using course microelectrodes. Functional maps covering the exposed part of area 7 showed that purely visual and oculomotor responses occurred in area 7a (PG) whereas the skin was dominantly represented in area 7b (PF).

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Dec
1969

(1) In functional squints, it is necessary to assess, in each case, the exact and particular role played by innervational and viscoelastic impairments by carrying out a thorough clinical examination, an electro-oculographic recording and the anesthetic and muscle elongation tests. Such as appraisal is still only approximate, however. (2) Various surgical methods permit the suppression of the deviation but all the procedures are purely empirical, and their results have no pathogenetic significance.

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