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1.
Annu Rev Vis Sci ; 5: 201-221, 2019 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-31525140

RESUMO

Numerous studies have demonstrated the impact of imposed abnormal visual experience on the postnatal development of the visual system. These studies have provided fundamental insights into the mechanisms underlying neuroplasticity and its role in clinical care. However, the ocular motor responses of postnatal human infants largely define their visual experience in dynamic three-dimensional environments. Thus, the immature visual system needs to control its own visual experience. This review explores the interaction between the developing motor and sensory/perceptual visual systems, together with its importance in both typical development and the development of forms of strabismus and amblyopia.


Assuntos
Nervo Oculomotor/fisiologia , Visão Ocular/fisiologia , Percepção Visual/fisiologia , Acomodação Ocular/fisiologia , Ambliopia/fisiopatologia , Humanos , Hiperopia/fisiopatologia , Lactente , Recém-Nascido , Fenômenos Fisiológicos Oculares , Estrabismo/fisiopatologia , Visão Binocular/fisiologia
2.
Anat Rec (Hoboken) ; 302(3): 446-451, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29663710

RESUMO

The oculomotor (OM) complex is a combination of somatic and parasympatethic neurons. The correct development and wiring of this cranial pair is essential to perform basic functions: eyeball and eyelid movements, pupillary constriction, and lens accommodation. The improper formation or function of this nucleus leads pathologies such as strabismus. We describe the OM organization and function in different vertebrate brains, including chick, mouse, and human. The morphological localization is detailed, as well as the spatial relation with the trochlear nucleus in order to adjust some misleading anatomical topographic descriptions. We detailed the signaling processes needed for the specification of the OM neurons. The transcriptional programs driven the specification and differentiation of these neurons are partially determined. We summarized recent genetic studies that have led to the identification of guidance mechanisms involved in the migration, axon pathfinding, and targeting of the OM neurons. Finally, we overviewed the pathology associated to genetic malformations in the OM development and related clinical alterations. Anat Rec, 302:446-451, 2019. © 2018 Wiley Periodicals, Inc.


Assuntos
Nervos Cranianos/fisiologia , Movimentos Oculares/fisiologia , Neurônios Motores/fisiologia , Vias Neurais , Nervo Oculomotor/fisiologia , Animais , Diferenciação Celular , Movimento Celular , Galinhas , Nervos Cranianos/citologia , Humanos , Camundongos , Neurônios Motores/citologia , Nervo Oculomotor/citologia
3.
Nat Commun ; 9(1): 2907, 2018 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-30046066

RESUMO

A perceptual judgment is typically characterized by constructing psychometric and chronometric functions, i.e., by mapping the accuracies and reaction times of motor choices as functions of a sensory stimulus feature dimension. Here, we show that various saccade metrics (e.g., peak velocity) are similarly modulated as functions of sensory cue viewing time during performance of an urgent-decision task. Each of the newly discovered functions reveals the dynamics of the perceptual evaluation process inherent to the underlying judgment. Remarkably, saccade peak velocity correlates with statistical decision confidence, suggesting that saccade kinematics reflect the degree of certainty with which an urgent perceptual decision is made. The data were explained by a race-to-threshold model that also replicates standard performance measures and cortical oculomotor neuronal activity in the task. The results indicate that, although largely stereotyped, saccade metrics carry subtle but reliable traces of the underlying cognitive processes that give rise to each oculomotor choice.


Assuntos
Tomada de Decisões/fisiologia , Animais , Comportamento de Escolha/fisiologia , Macaca mulatta , Masculino , Modelos Teóricos , Nervo Oculomotor/fisiologia
4.
Nat Neurosci ; 21(5): 736-743, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29662213

RESUMO

The primary output cells of the cerebellar cortex, Purkinje cells, make kinematic predictions about ongoing movements via high-frequency simple spikes, but receive sensory error information about that movement via low-frequency complex spikes (CS). How is the vector space of sensory errors encoded by this low-frequency signal? Here we measured Purkinje cell activity in the oculomotor vermis of animals during saccades, then followed the chain of events from experience of visual error, generation of CS, modulation of simple spikes, and ultimately change in motor output. We found that while error direction affected the probability of CS, error magnitude altered its temporal distribution. Production of CS changed the simple spikes on the next trial, but regardless of the actual visual error, this change biased the movement only along a vector that was parallel to the Purkinje cell's preferred error. From these results, we inferred the anatomy of a sensory-to-motor adaptive controller that transformed visual error vectors into motor-corrections.


Assuntos
Cerebelo/fisiologia , Aprendizagem/fisiologia , Células de Purkinje/fisiologia , Animais , Comportamento Animal/fisiologia , Fenômenos Biomecânicos/fisiologia , Córtex Cerebelar/citologia , Córtex Cerebelar/fisiologia , Cerebelo/citologia , Fenômenos Eletrofisiológicos/fisiologia , Macaca mulatta , Nervo Oculomotor/citologia , Nervo Oculomotor/fisiologia , Desempenho Psicomotor/fisiologia , Movimentos Sacádicos
5.
J Clin Neurophysiol ; 35(1): 11-15, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29298208

RESUMO

The utility of extraocular cranial nerve electrophysiologic recordings lies primarily in the operating room during skull base surgeries. Surgical manipulation during skull base surgeries poses a risk of injury to multiple cranial nerves, including those innervating extraocular muscles. Because tumors distort normal anatomic relationships, it becomes particularly challenging to identify cranial nerve structures. Studies have reported the benefits of using intraoperative spontaneous electromyographic recordings and compound muscle action potentials evoked by electrical stimulation in preventing postoperative neurologic deficits. Apart from surgical applications, electromyography of extraocular muscles has also been used to guide botulinum toxin injections in patients with strabismus and as an adjuvant diagnostic test in myasthenia gravis. In this article, we briefly review the rationale, current available techniques to monitor extraocular cranial nerves, technical difficulties, clinical and surgical applications, as well as future directions for research.


Assuntos
Nervo Abducente/fisiologia , Eletromiografia/métodos , Músculos Oculomotores/inervação , Músculos Oculomotores/fisiologia , Nervo Oculomotor/fisiologia , Nervo Troclear/fisiologia , Nervo Abducente/fisiopatologia , Humanos , Procedimentos Neurocirúrgicos , Músculos Oculomotores/fisiopatologia , Nervo Oculomotor/fisiopatologia , Nervo Troclear/fisiopatologia
6.
Int. j. psychol. psychol. ther. (Ed. impr.) ; 18(1): 15-26, ene. 2018. graf, tab
Artigo em Inglês | IBECS | ID: ibc-171368

RESUMO

With an aim to examine behavioural and physiological changes during emotion elicitation, 30 participants were shown audio, video or audio-video versions of movie clips depicting anger, fear, happiness, sadness, surprise and neutral expressions. While watching these stimuli, the eye-tracking glass was used to record oculomotoric changes. Heart rate, blood volume and respiration rate were also recorded. After viewing each clip the participants had to label and rate the emotion depicted in the movie clip. The data was analyzed with respect to valence, motoric direction and arousal dimensions of emotions. Findings of the behavioural data and corresponding change in the respiration rate suggest that fear is the only emotion that equally impacted participants psychologically as well as physiologically. The number of fixations and saccades for positive and negative emotions differed significantly (AU)


No disponible


Assuntos
Humanos , Nervo Oculomotor/fisiologia , Emoções/fisiologia , Biorretroalimentação Psicológica , Pressão Sanguínea/fisiologia , Volume Sanguíneo/fisiologia , Movimentos Oculares/fisiologia
7.
Acta Ophthalmol ; 96(2): e111-e118, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27874249

RESUMO

PURPOSE: To evaluate the role of neural integrators (NI) in the oculomotor system. METHODS: A literature search was carried out using several electronic databases during the months of June 2014 to March 2015. The following keywords were used to generate focused results: 'neural integrators', 'gaze-holding', 'oculomotor integration', 'impaired gaze-holding', 'gaze evoked nystagmus' and 'gaze dysfunction'. Further materials were found through searching relevant articles within reference lists. Seventy-one articles were sourced for this review which analysed animal and human subjects and network models; 45 were studies of humans, 16 studies of primates, three studies of felines and one study from rats and network models. The remaining articles were literature reviews. RESULTS: The horizontal and vertical, including torsional, NI are located logically in the brainstem, nearby their appropriate target extraocular motoneuron nuclei for stable eye position in eccentric position. The nucleus prepositus hypoglossi (NPH) and medial vestibular nuclei (MVN) are closely linked at the caudal pons and dorsal rostral medulla, integrating horizontal conjugate eye movement. The interstitial nucleus of Cajal (INC) integrates vertical and torsional eye movement at the upper midbrain. The integrator time constant is averaged to 25 seconds in human horizontal and animal vertical NI to perform its function. Case reports revealed that dysfunction of horizontal NI also resulted in vertical ocular deviations, indicating some overlap of horizontal and vertical gaze control. Furthermore, pharmacological inactivation of NI exposed a population of inhibitory neurotransmitters that permits its mechanism of action; allowing for smooth conjugate movement. CONCLUSIONS: Neural integrators operate to integrate eye velocity and eye position information to provide signals to extraocular motoneurons to attain and maintain a new position. Therefore, NI allow image stabilization during horizontal and vertical eye movements at eccentric positions for comfortable single vision.


Assuntos
Movimentos Oculares/fisiologia , Fixação Ocular/fisiologia , Nervo Oculomotor/fisiologia , Células Receptoras Sensoriais/fisiologia , Animais , Humanos , Campos Visuais/fisiologia
8.
Klin Monbl Augenheilkd ; 234(11): 1334-1343, 2017 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-28898914

RESUMO

After just a clinical examination, the experienced neurologist can assign specific symptoms quite precisely to distinct lesions within the brain and other parts of the nervous system, on the basis of his neuroanatomical knowledge. This also holds true for lesions affecting the oculomotor system. The aim of this article is to give a comprehensive overview of the neuroanatomical basis of the oculomotor system, in order to facilitate the precise spatial assignment of potential lesions affecting the control of eye movements. After a brief introduction, the components of the system are discussed, including the extraocular muscles and their innervating nerves. The following section will then cover the control of eye movements and will specifically address distinct patterns of eye movements and areas within the central nervous system controlling these. This article also gives a brief overview of the intraocular muscles and their control.


Assuntos
Movimentos Oculares/fisiologia , Nervo Oculomotor/anatomia & histologia , Acomodação Ocular/fisiologia , Mapeamento Encefálico , Convergência Ocular/fisiologia , Corpos Geniculados/anatomia & histologia , Corpos Geniculados/fisiologia , Mesencéfalo/anatomia & histologia , Mesencéfalo/fisiologia , Vias Neurais/anatomia & histologia , Vias Neurais/fisiologia , Neurônios/ultraestrutura , Músculos Oculomotores/inervação , Nervo Oculomotor/fisiologia , Trato Óptico/anatomia & histologia , Trato Óptico/fisiologia , Acompanhamento Ocular Uniforme/fisiologia , Reflexo Pupilar/fisiologia , Movimentos Sacádicos/fisiologia , Medula Espinal/anatomia & histologia , Medula Espinal/fisiologia , Vias Visuais/anatomia & histologia , Vias Visuais/fisiologia
9.
Strabismus ; 25(3): 156-159, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28771056

RESUMO

PURPOSE: To assess the ocular motor functions in children with spastic hemiplegia by using the Ocular Motor Score (OMS). MATERIAL: This study included 34 children, median age 11 years. The children were divided into 3 groups according to the underlying brain lesion; group 1 malformations, group 2 white matter damage of immaturity (WMDI), and group 3 cortical/subcortical lesions. METHODS: The OMS protocol consists of 15 different subtests evaluating ocular motor functions. The OMS is divided into 2 parts, a static and a dynamic. The results from each subtest are scored 0, 0.3, 0.5, or 1, according to the level of disturbance, where 0 corresponds to normal function and 1 represents the maximum disability in the certain subtest. A total OMS (tOMS) between 0 and 15 can be obtained. RESULTS: The median tOMS in the whole spastic hemiplegia group was 2.5 (range 1.3-5.8). The highest median tOMS 5.2 was seen in group 1, in the children with malformations. Strabismus was found in 45% (15/34) of the children, with an equal percentage in all 3 groups. CONCLUSIONS: The children with spastic hemiplegia had a median tOMS of 2.7 and the highest median tOMS was seen in children with malformations. The OMS protocol is easy to use clinically and gives a quick overview of the patient´s ocular motor functions.


Assuntos
Técnicas de Diagnóstico Oftalmológico , Hemiplegia/fisiopatologia , Nervo Oculomotor/fisiologia , Adolescente , Paralisia Cerebral/complicações , Criança , Pré-Escolar , Convergência Ocular , Feminino , Fixação Ocular/fisiologia , Hemiplegia/etiologia , Humanos , Masculino , Fenômenos Fisiológicos Oculares , Reflexo Vestíbulo-Ocular/fisiologia , Movimentos Sacádicos/fisiologia
10.
Acta Neurochir (Wien) ; 159(10): 1925-1937, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28766024

RESUMO

BACKGROUND: Intraoperative neurophysiologic monitoring of the extraocular cranial nerve (EOCN) is not commonly performed because of technical difficulty and risk, reliability of the result and predictability of the postoperative function of the EOCN. METHODS: We performed oculomotor nerve (CN III) and abducens nerve (CN VI) intraoperative monitoring in patients with skull base surgery by recording the spontaneous muscle activity (SMA) and compound muscle action potential (CMAP). Two types of needle electrodes of different length were percutaneously inserted into the extraocular muscles with the free-hand technique. We studied the relationships between the SMA and CMAP and postoperative function of CN III and CN VI. RESULTS: A total of 23 patients were included. Nineteen oculomotor nerves and 22 abducens nerves were monitored during surgery, respectively. Neurotonic discharge had a positive predictive value of less than 50% and negative predictive value of more than 80% for postoperative CN III and CN VI dysfunction. The latency of patients with postoperative CN III dysfunction was 2.79 ± 0.13 ms, longer than that with intact CN III function (1.73 ± 0.11 ms). One patient had transient CN VI dysfunction, whose CMAP latency (2.54 ms) was longer than that of intact CN VI function (2.11 ± 0.38 ms). There was no statistically significant difference between patients with paresis and with intact function. CONCLUSIONS: The method of intraoperative monitoring of EOCNs described here is safe and useful to record responses of SMA and CMAP. Neurotonic discharge seems to have limited value in predicting the postoperative function of CN III and CN VI. The onset latency of CMAP longer than 2.5 ms after tumor removal is probably relevant to postoperative CN III and CN VI dysfunction. However, a definite quantitative relationship has not been found between the amplitude and stimulation intensity of CMAP and the postoperative outcome of CN III and CN VI.


Assuntos
Nervo Abducente/cirurgia , Eletromiografia/métodos , Monitorização Neurofisiológica Intraoperatória/métodos , Nervo Oculomotor/cirurgia , Base do Crânio/cirurgia , Nervo Abducente/fisiologia , Adolescente , Adulto , Idoso , Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/métodos , Nervo Oculomotor/fisiologia , Procedimentos Ortopédicos/métodos , Reprodutibilidade dos Testes , Adulto Jovem
11.
Invest Ophthalmol Vis Sci ; 58(4): 2388-2396, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28437527

RESUMO

Purpose: To spatially and temporally define ocular motor nerve development in the presence and absence of extraocular muscles (EOMs). Methods: Myf5cre mice, which in the homozygous state lack EOMs, were crossed to an IslMN:GFP reporter line to fluorescently label motor neuron cell bodies and axons. Embryonic day (E) 11.5 to E15.5 wild-type and Myf5cre/cre:IslMN:GFP whole mount embryos and dissected orbits were imaged by confocal microscopy to visualize the developing oculomotor, trochlear, and abducens nerves in the presence and absence of EOMs. E11.5 and E18.5 brainstems were serially sectioned and stained for Islet1 to determine the fate of ocular motor neurons. Results: At E11.5, all three ocular motor nerves in mutant embryos approached the orbit with a trajectory similar to that of wild-type. Subsequently, while wild-type nerves send terminal branches that contact target EOMs in a stereotypical pattern, the Myf5cre/cre ocular motor nerves failed to form terminal branches, regressed, and by E18.5 two-thirds of their corresponding motor neurons died. Comparisons between mutant and wild-type embryos revealed novel aspects of trochlear and oculomotor nerve development. Conclusions: We delineated mouse ocular motor nerve spatial and temporal development in unprecedented detail. Moreover, we found that EOMs are not necessary for initial outgrowth and guidance of ocular motor axons from the brainstem to the orbit but are required for their terminal branching and survival. These data suggest that intermediate targets in the mesenchyme provide cues necessary for appropriate targeting of ocular motor axons to the orbit, while EOM cues are responsible for terminal branching and motor neuron survival.


Assuntos
Movimentos Oculares/fisiologia , Músculos Oculomotores/embriologia , Nervo Oculomotor/embriologia , Animais , Axônios/fisiologia , Camundongos , Microscopia Confocal , Modelos Animais , Neurônios Motores/fisiologia , Músculos Oculomotores/inervação , Nervo Oculomotor/fisiologia
12.
Ann Plast Surg ; 78(3 Suppl 2): S58-S60, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28195895

RESUMO

BACKGROUND: Involutional blepharoptosis is the most common type of acquired blepharoptosis. The etiology is believed to be the degeneration of the levator aponeurosis, and levator superioris muscle function was believed to be normal. However, there are a few studies analyzing levator function (LF) in involutional blepharoptosis. Our study aimed to access the LF abnormality in involutional blepharoptosis and analyze the correlation between LF and ptosis severity in involutional blepharoptosis in Taiwan. METHODS: We reviewed the medical records of patients who underwent ptosis correction surgery between October 2011 and December 2015 after receiving a diagnosis of involutional blepharoptosis. This study examined patient sex and age, preoperative LF, margin reflex distance of the upper eyelid (MRD1), and ptosis severity. Linear regression was performed for statistical analysis. Levator muscle specimen was sent for pathologic examination. RESULTS: We analyzed 231 eyelids of 126 patients. Average MRD1 was 0.43 ± 2.15 mm. Average LF was 14.30 ± 2.51 mm. Overall, 77.1% (178/231) of involutional blepharoptotic eyelids had normal LF (more than 12 mm). Forty-three (18.6%) of 231 were good (10-12 mm), and 10 (4.3%) of 231 were fair (6-9 mm). No patients with poor levator function (≤5 mm) were observed in our case series. A positive correlation between LF and MRD1 was observed after statistical analysis. On average, a 0.6-mm reduction in LF was observed for each 1.0-mm decrease in MRD1. Fat infiltration in levator muscle is observed both grossly and microscopically in most cases with varied degrees. CONCLUSIONS: Levator function and MRD1 were positively correlated in patients with involutional blepharoptosis. In our study, 77.1% (178/231) of eyelids had normal levator function, which meant there was 23.0% (53/231) of eyelids had abnormal LF, in contrast to current literature. Fat infiltration was common in our series. In Asian involutional blepharoptosis, LF was not always excellent and it had positive correlation with ptosis severity.


Assuntos
Blefaroptose/fisiopatologia , Blefaroptose/cirurgia , Músculos Oculomotores/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculos Oculomotores/inervação , Nervo Oculomotor/fisiologia , Estudos Retrospectivos , Índice de Gravidade de Doença , Taiwan , Resultado do Tratamento
13.
J Neural Eng ; 14(4): 046007, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28098561

RESUMO

OBJECTIVE: To date, invasive brain-computer interface (BCI) research has largely focused on replacing lost limb functions using signals from the hand/arm areas of motor cortex. However, the oculomotor system may be better suited to BCI applications involving rapid serial selection from spatial targets, such as choosing from a set of possible words displayed on a computer screen in an augmentative and alternative communication (AAC) application. Here we aimed to demonstrate the feasibility of a BCI utilizing the oculomotor system. APPROACH: We developed a chronic intracortical BCI in monkeys to decode intended saccadic eye movement direction using activity from multiple frontal cortical areas. MAIN RESULTS: Intended saccade direction could be decoded in real time with high accuracy, particularly at contralateral locations. Accurate decoding was evident even at the beginning of the BCI session; no extensive BCI experience was necessary. High-frequency (80-500 Hz) local field potential magnitude provided the best performance, even over spiking activity, thus simplifying future BCI applications. Most of the information came from the frontal and supplementary eye fields, with relatively little contribution from dorsolateral prefrontal cortex. SIGNIFICANCE: Our results support the feasibility of high-accuracy intracortical oculomotor BCIs that require little or no practice to operate and may be ideally suited for 'point and click' computer operation as used in most current AAC systems.


Assuntos
Interfaces Cérebro-Computador , Eletrodos Implantados , Nervo Oculomotor/fisiologia , Estimulação Luminosa/métodos , Córtex Pré-Frontal/fisiologia , Movimentos Sacádicos/fisiologia , Animais , Macaca fascicularis , Macaca mulatta , Masculino , Distribuição Aleatória
14.
PLoS One ; 11(12): e0168245, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27992486

RESUMO

PURPOSE: To clarify the efficacy of a surgical strategy based on the superior oblique tendon traction test. METHODS: A retrospective chart review was performed between January 2002 and June 2015. During that period, a single inferior oblique muscle (IO) myectomy and a combined IO myectomy and superior oblique muscle (SO) tuck procedure were performed based on SO tendon looseness as revealed by a traction test. The surgical effects of both procedures and the number of operations were analyzed. RESULTS: Sixty-five cases were retrieved. Seventy-four surgeries were required. The IO myectomy and simultaneous groups included 48 and 17 cases, respectively. Pre-operative vertical deviation was significantly lower in the IO myectomy (11.8 prism diopters) than in the simultaneous (27.2 prism diopters; Mann-Whitney U-test, P < 0.001) group. The mean induced changes were 9.4 prism diopters and 21.6 prism diopters in the IO myectomy and simultaneous groups, respectively, and the postoperative vertical deviation was not significantly different. On average, 1.13 and 1.18 surgeries per patient were performed in the IO myectomy and simultaneous groups, respectively. CONCLUSION: The simultaneous surgery of inferior oblique myectomy and superior oblique tuck is safe and effective for treating large angle of congenital/idiopathic superior oblique palsy with a lax superior oblique tendon, as determined by the traction test.


Assuntos
Monitorização Intraoperatória/métodos , Nervo Oculomotor/fisiologia , Procedimentos Cirúrgicos Oftalmológicos/métodos , Tendões/fisiologia , Tração , Doenças do Nervo Troclear/congênito , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Humanos , Lactente , Pessoa de Meia-Idade , Contração Muscular , Músculos Oculomotores/fisiologia , Músculos Oculomotores/cirurgia , Nervo Oculomotor/cirurgia , Estudos Retrospectivos , Tendões/cirurgia , Doenças do Nervo Troclear/cirurgia , Adulto Jovem
15.
PLoS One ; 11(10): e0164885, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27764173

RESUMO

Paediatric cerebral malaria is the most serious complication of Plasmodium falciparum infection. While the majority recover, long-term cognitive impairment has been highlighted as a significant and neglected problem. Persistent or serious deficits in processes such as attention or behavioural inhibition should be manifest in changes to performance on oculomotor tasks. Therefore we investigated the impact of cerebral malaria on the development of reflexive pro-saccades and antisaccades. In a longitudinal study, 47 children previously admitted with retinopathy-confirmed cerebral malaria (mean age at admission 54 months), were compared with 37 local healthy controls (mean ages at first study visit 117 and 110 months respectively). In each of three or four test sessions, over a period of up to 32 months, participants completed 100 prosaccade tasks and 100 antisaccade tasks. Eye movements were recorded using infrared reflectance oculography; prosaccade, correct antisaccade and error prosaccade latency, and antisaccade directional error rate were calculated. Hierarchical linear modelling was used to investigate the effect of age and the influence of cerebral malaria on these parameters. Data were also collected from an independent, older group (mean age 183 months) of 37 local healthy participants in a separate cross-sectional study. Longitudinal data exhibited the expected decrease in latency with age for all saccade types, and a decrease in the antisaccade directional error rate. Hierarchical linear modelling confirmed that age had a statistically significant effect on all parameters (p< = 0.001). However, there were no statistically significant differences between the cerebral malaria and control groups. Combining groups, comparison with the literature demonstrated that antisaccade directional error rate for the Malawi sample was significantly higher than expected, while latencies for all saccade types were indistinguishable from published. The high directional error rate was also confirmed in the older, healthy Malawian participants from the cross sectional study. Our observation of similar oculomotor performance in cerebral malaria and control groups at long follow-up periods suggests that cerebral malaria survivors are not at a generally increased risk of persistent cognitive deficits. Our data raise questions about the prevailing hypothesis that cerebral malaria has gross impacts on the development of processes such as attention and behavioural inhibition. More importantly, our novel finding of a clear difference in antisaccade performance between all of the Malawi participants and published data suggests that the Malawian paediatric population as a whole faces serious challenges to cognitive development beyond cerebral malaria.


Assuntos
Malária Cerebral/diagnóstico , Nervo Oculomotor/crescimento & desenvolvimento , Adolescente , Fatores Etários , Estudos de Casos e Controles , Criança , Pré-Escolar , Movimentos Oculares/fisiologia , Feminino , Humanos , Modelos Lineares , Estudos Longitudinais , Malária Cerebral/complicações , Malaui , Masculino , Nervo Oculomotor/fisiologia , Movimentos Sacádicos/fisiologia
16.
Brain Behav ; 5(3): e00310, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25642393

RESUMO

INTRODUCTION: An essential complement to molecular-genetic approaches for analyzing the function of the oculomotor circuitry in mice is an understanding of sensory and motor signal processing in the circuit. Although there has been extensive analysis of the signals carried by neurons in the oculomotor circuits of species, such as monkeys, rabbits and goldfish, relatively little in vivo physiology has been done in the oculomotor circuitry of mice. We analyzed the contribution of vestibular and nonvestibular signals to the responses of individual Purkinje cells in the cerebellar flocculus of mice. METHODS: We recorded Purkinje cells in the cerebellar flocculus of C57BL/6 mice during eye movement responses to vestibular and visual stimulation. RESULTS: As in other species, most individual Purkinje cells in mice carried both vestibular and nonvestibular signals, and the most common response across cells was an increase in firing in response to ipsiversive eye movement or ipsiversive head movement. When both the head and eyes were moving, the Purkinje cell responses were approximated as a linear summation of head and eye velocity inputs. Unlike other species, floccular Purkinje cells in mice were considerably more sensitive to eye velocity than head velocity. CONCLUSIONS: The signal content of Purkinje cells in the cerebellar flocculus of mice was qualitatively similar to that in other species. However, the eye velocity sensitivity was higher than in other species, which may reflect a tuning to the smaller range of eye velocities in mice.


Assuntos
Potenciais de Ação/fisiologia , Movimentos Oculares/fisiologia , Movimentos da Cabeça/fisiologia , Células de Purkinje/fisiologia , Reflexo Vestíbulo-Ocular , Animais , Fenômenos Eletrofisiológicos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Nervo Oculomotor/fisiologia , Estimulação Luminosa , Estimulação Física
17.
Invest Ophthalmol Vis Sci ; 56(3): 1594-600, 2015 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-25670485

RESUMO

PURPOSE: Infantile nystagmus (IN) is a pathological, involuntary oscillation of the eyes consisting of slow, drifting eye movements interspersed with rapid reorienting quick phases. The extent to which quick phases of IN are programmed similarly to saccadic eye movements remains unknown. We investigated whether IN quick phases exhibit 'saccadic inhibition,' a phenomenon typically related to normal targeting saccades, in which the initiation of the eye movement is systematically delayed by task-irrelevant visual distractors. METHODS: We recorded eye position from 10 observers with early-onset idiopathic nystagmus while task-irrelevant distractor stimuli were flashed along the top and bottom of a large screen at ±10° eccentricity. The latency distributions of quick phases were measured with respect to these distractor flashes. Two additional participants, one with possible albinism and one with fusion maldevelopment nystagmus syndrome, were also tested. RESULTS: All observers showed that a distractor flash delayed the execution of quick phases that would otherwise have occurred approximately 100 ms later, exactly as in the standard saccadic inhibition effect. The delay did not appear to differ between the two main nystagmus types under investigation (idiopathic IN with unidirectional and bidirectional jerk). CONCLUSIONS: The presence of the saccadic inhibition effect in IN quick phases is consistent with the idea that quick phases and saccades share a common programming pathway. This could allow quick phases to take on flexible, goal-directed behavior, at odds with the view that IN quick phases are stereotyped, involuntary eye movements.


Assuntos
Atenção/fisiologia , Inibição Neural/fisiologia , Nistagmo Patológico/congênito , Orientação/fisiologia , Movimentos Sacádicos/fisiologia , Percepção Visual/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Nistagmo Optocinético/fisiologia , Nistagmo Patológico/diagnóstico , Nistagmo Patológico/fisiopatologia , Nervo Oculomotor/fisiologia , Estimulação Luminosa , Adulto Jovem
18.
Eye (Lond) ; 29(2): 246-51, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25572578

RESUMO

We review ocular motor cranial nerve palsies in childhood and highlight many of the features that differentiate these from their occurrence in adulthood. The clinical characteristics of cranial nerve palsies in childhood are affected by the child's impressive ability to repair and regenerate after injury. Thus, aberrant regeneration is very common after congenital III palsy; Duane syndrome, the result of early repair after congenital VI palsy, is invariably associated with retraction of the globe in adduction related to the innervation of the lateral rectus by the III nerve causing co-contraction in adduction. Clinical features that may be of concern in adulthood may not be relevant in childhood; whereas the presence of mydriasis in III palsy suggests a compressive aetiology in adults, this is not the case in children. However, the frequency of associated CNS abnormalities in III palsy and the risk of tumour in VI palsy can be indications for early neuroimaging depending on presenting features elicited through a careful history and clinical examination. The latter should include the neighbouring cranial nerves. We discuss the impact of our evolving knowledge of congenital cranial dysinnervation syndromes on this field.


Assuntos
Doenças do Nervo Abducente/fisiopatologia , Oftalmopatias/fisiopatologia , Doenças do Nervo Oculomotor/fisiopatologia , Doenças do Nervo Troclear/fisiopatologia , Nervo Abducente/fisiologia , Doenças do Nervo Abducente/etiologia , Criança , Pré-Escolar , Humanos , Regeneração Nervosa/fisiologia , Nervo Oculomotor/fisiologia , Doenças do Nervo Oculomotor/etiologia , Nervo Troclear/fisiologia , Doenças do Nervo Troclear/etiologia
19.
Adv Med Sci ; 60(1): 25-30, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25262200

RESUMO

PURPOSE: We analyzed the usefulness and prognostic value of intraoperative monitoring for identification of the oculomotor (III) and the abducens (VI) nerve in patients with cavernous sinus meningiomas. MATERIAL/METHODS: 43 patients diagnosed with cavernous sinus meningiomas were divided according to their topography. Function of the nerves was scored on original clinical and neurophysiological scales. RESULTS: The percentage of nerves identified correctly with the monitoring was significantly higher (91% vs. 53% for nerve III and 70% vs. 23% for nerve VI, p<0.001). The fractions of nerves III and VI identified correctly by means of the monitoring were significantly higher in the case of tumors with intra- and extracavernous location (89% vs. 32%, p<0.01) and intracavernous tumors (80% vs. 20%, p<0.05), respectively. The quality of post-resection recording correlated with functional status of both the nerves determined 9 months after the surgery (R=0.51, p<0.001 for nerve III and R=0.57, p<0.01 for nerve VI). Even a trace or pathological response to the post-resection stimulation was associated with improved functional status (90% vs. 50%, p<0.05 for nerve III and 93% vs. 38%, p<0.01 for nerve VI). CONCLUSIONS: Neurophysiological monitoring of ocular motor nerves enables their intraoperative identification during resections of the cavernous sinus meningiomas. Intraoperative monitoring of nerve III is particularly important in the case of tumors with extra- and intracavernous location, and the monitoring of nerve VI in the case of intracavernous tumors. The outcome of the post-resection monitoring has prognostic value with regard to the clinical status of the nerves on long-term follow-up.


Assuntos
Nervo Abducente/fisiologia , Seio Cavernoso/cirurgia , Neoplasias Meníngeas/cirurgia , Meningioma/cirurgia , Monitorização Intraoperatória/métodos , Nervo Oculomotor/fisiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
20.
J Mol Neurosci ; 54(4): 639-52, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25022883

RESUMO

The oculomotor nerve can regenerate anatomically and histologically after injury; however, the degree of functional recovery of extraocular muscles and the pupil sphincter muscle was not satisfactory. Electrostimulation was one potential intervention that was increasingly being studied for use in nerve injury settings. However, the effect of electrostimulation on regeneration of the injured oculomotor nerve was still obscure. In this study, we studied the effects of electrostimulation on neural regeneration in terms of neurofunction, myoelectrophysiology, neuroanatomy, and neurohistology after oculomotor nerve injury and found that electrostimulation on the injured oculomotor nerve enhanced the speed and final level of its functional and electrophysiological recovery, promoted neural regeneration, and enhanced the selectivity and specificity of reinnervation of the regenerated neuron, the conformity among the electrophysiological and functional recovery of extraocular muscles, and neural regeneration, and that the function of extraocular muscles recovered slower than electrophysiology. Thus, we speculated that electrostimulation on the injured oculomotor nerve produced a marked effect on all phases of neural regeneration including neuronal survival, sprout formation, axonal elongation, target reconnection, and synaptogenesis. We think that neural electrostimulation can be used in oculomotor nerve injury.


Assuntos
Terapia por Estimulação Elétrica , Regeneração Nervosa , Traumatismos do Nervo Oculomotor/terapia , Nervo Oculomotor/fisiologia , Animais , Cães
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