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1.
背景:研究表明,固视期间的眼动,不仅包含了来自神经系统的噪声信号,而且包含认知加工的信息,固视成分及其功能的研究也日益引起重视。目的:综述固视成分分离的研究现状及进展。方法:分别以“visualfixation,fixationaleyemovement,tremor.drifts,microsaccades”为关键词,利用计算机检索1980至2012年PebMed数据库,并使用Google学术进行相关文献搜索,以及参考相应专著,排除内容重复、无关及缺乏原创性的文献,保留64篇文献做进一步分析。结果与结论:固视是个体的眼睛保持对准被观察物体的一种现象,伴随有微颤、漂移和微跳视3种眼动成分,它们是维持视知觉的重要条件。近年来,研究者针对固视3种成分对视知觉的贡献进行了探讨,主要包括防止知觉消退和对视觉系统进行纠错两种观点。目前,研究者通过对眼动速度阈限的估计来分离微跳视成分。未来的研究可以从固视眼动的神经生理基础以及神经活动的记录技术和视网膜固定技术的提高等方面展开,从而加深对固视眼动现象的理解。  相似文献   

2.
Feedback of eye movements was evaluated as a treatment for visual neglect in right hemisphere stroke patients. Patients with visual neglect identified on the Behavioural Inattention Test (BIT) were randomly allocated to two groups. One group (n = 9) was treated for 2 h 40 min a week for 4 weeks, by wearing glasses which provided a reminder bleep if patients failed to move their eyes to the left in a 15 s interval. The control group (n = 9) received no treatment for their visual inattention. Comparison of the groups after 4 weeks treatment and a further 4 weeks follow-up showed no significant difference either in eye movements or on the BIT. However, there was a trend towards a difference between eye movements in the two groups at 8 weeks, suggesting treatment may have influenced eye movements without changing neglect.  相似文献   

3.
Effect of eye movements on dynamic equilibrium   总被引:1,自引:0,他引:1  
The purpose of this study was to determine whether visual improvement of balance varies depending on the movement of the eye. Three movements were compared: static visual fixations, saccadic eye movements, and smooth pursuit eye movements. The subjects in this study were 35 healthy female volunteers. Balance was defined as the subjects' ability to maintain their equilibrium while keeping the unstable platform on which they stood within 5 degrees of the horizontal plane. The testing protocol consisted of five recorded practice trials, during which the subjects tried to maintain their balance without any visual instructions, and nine experimental trials, during which they tried to maintain their balance while visually following a videotaped target light projected onto a screen. The target light was sequenced randomly to remain stationary, move in a continuous horizontal path, or alternately jump between right and left. Data were analyzed using a one-way multivariate analysis of variance for repeated measures. A significant effect of vision on balance was found. The t tests for correlated samples revealed that time in balance during visual fixations and saccades was significantly longer than during tracking eye movements. We, therefore, concluded that tracking eye movements have a negative effect on balance. This information can be useful in treating patients with balance problems. For example, instructing patients to fixate visually on an object may aid their stability. Visual tracking of a moving limb, however, may impair a patient's stability.  相似文献   

4.
Since 1981, when eye movements of the human fetus were first reported, the study of fetal eye movements has increased, mainly focusing on the ontogenesis of eye movements and as one parameter of behavioral states. Using real-time ultrasound, fetal eye movements can be clearly observed from 14 weeks of gestational age. Fetal eye movements may be described in terms of their pattern, frequency and incidence of periods containing eye movements and no eye movements. Furthermore, the relationship of eye movements to other behaviors may be used to give information on the integration of central nervous system function. A picture of normal fetal eye movements can be constructed and used to detect abnormalities in eye movements which can indicate underlying abnormalities of the central nervous system. This paper concludes that, although in its early stages, the study of fetal eye movements holds promise for a greater understanding of brain development and the assessment of the condition of the fetus.  相似文献   

5.
目的 探讨哌甲酯对注意缺陷多动障碍儿童探究性眼动的影响.方法 将50例注意缺陷多动障碍患儿设为研究组,抽取同期体检的38名健康少年儿童设为对照组.研究组于口服哌甲酯前后进行探究性眼动检测,对照组进行常规探究性眼动检测,对两组检测结果进行对比分析.结果 研究组口服哌甲酯2 h后凝视点数目、反应性探究分测定结果均高于治疗前(P<0.05);服药前后凝视点数目、反应性探究分测定结果均低于对照组(P<0.01).结论 哌甲酯能显著改善注意缺陷多动障碍患儿的视觉认知功能.  相似文献   

6.
The vestibular system contributes to the generation of conjugate eye movements, spatial orientation, and postural control. The functional connections of the vestibular end-organs and of the descending vestibulospinal pathways and their importance to postural control were reviewed in the previous paper by Keshner and Cohen (pp. 320-330). This paper reviews the ascending vestibular pathways, the visual/vestibular interactions, and the role of the vestibular system in oculomotor control and spatial orientation.  相似文献   

7.
Monitoring eye movements is a critical aspect of experimental design for studies of spatial attention and visual perception. However, obtaining online eye-movement recordings has been technologically difficult during functional magnetic resonance (MR) imaging studies. Previous approaches to monitoring eye movements either have distorted the MR images or have shown MR-related interference in the recordings. We report a technique using long-range infrared video-oculography to record eye movements without causing artifacts in the MR images. Analysis of the MR signal from a phantom obtained with the eye-movement equipment turned on or off confirmed the absence of significant additional noise in the MR time series. Eye movements of three subjects were monitored while they performed tasks of covert and overt shifts of spatial attention. Activation of the frontal eye fields during the covert task was seen even when the eye-movement recordings demonstrated no significant difference in saccadic eye movements between the baseline and the active conditions.  相似文献   

8.
Robust registration procedures for endoscopic imaging   总被引:1,自引:0,他引:1  
This paper presents a robust algorithm for calibration and system registration of endoscopic imaging devices. The system registration allows us to map accurately each point in the world coordinate system into the endoscope image and vice versa to obtain the world line of sight for each image pixel. The key point of our system is a robust linear algorithm based on singular value decomposition (SVD) for estimating simultaneously two unknown coordinate transformations. We show that our algorithm is superior in terms of robustness and computing efficiency to iterative procedures based on Levenberg-Marquardt optimization or on quaternion approaches. The algorithm does not require the calibration pattern to be tracked. Experimental results and simulations verify the robustness and usefulness of our approach. They give an accuracy of less than 0.7 mm and a success rate >99%. We apply the calibrated endoscope to the neurosurgical relevant case of red out, where in spite of the complete loss of vision the surgeon gets visual aids in the endoscope image at the actual position, allowing him/her to manoeuvre a coagulation fibre into the right position. Finally, we outline how our registration algorithm can be used also for standard registration applications (establish the mapping between two sets of points). We propose our algorithm as a linear, non-iterative algorithm also for projective transformations and for 2D-3D-mappings. Thus, it can be seen as a generalization of the well-known Umeyama registration algorithm.  相似文献   

9.
Analysis of human eye pupil reactivity is a very valuable diagnostic method used mainly for evaluation of the condition of the autonomic nervous system and the visual system. The paper presents an experimental pupillometer built in the Institute of Physics of the Wroclaw University of Technology. The apparatus makes it possible to record and analyze pupillary light reflex and spontaneous changes in the pupil diameter during a session in the dark. The detector system used in the pupillometer allows us to record the pupil diameter at a rate of 90 Hz with a linear accuracy of 0.008 mm. In this paper, the proposed detection method, the principle of operation and calibration of the apparatus and the possibilities of the measurement system are presented.  相似文献   

10.
Abstract

In this paper, the development of an assisting system for laparoscopic surgical training is presented. With this system, we expect to facilitate the training process at the first stages of training in laparoscopic surgery and to contribute to an objective evaluation of surgical skills. To achieve this, we propose the insertion of multimedia contents and outlines of work adapted to the level of experience of trainees and the detection of the movements of the laparoscopic instrument into the monitored image. A module to track the instrument is implemented focusing on the tip of the laparoscopic tool. This tracking method does not need the presence of artificial marks or special colours to distinguish the instruments. Similarly, the system has another method based on visual tracking to localize support multimedia content in a stable position of the field of vision. Therefore, this position of the support content is adapted to the movements of the camera or the working area. Experimental results are presented to show the feasibility of the proposed system for assisting in laparoscopic surgical training.  相似文献   

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