汉字识别的眼动特性-字频效应及信道容量

用眼动测量方法,对字频为４×１０－３至１．６×１０－５范围内笔画数为４至１４的常用汉字进行识别实验,结果表明,汉字识别时间与笔画数无关,而是存在识别时间随字频减小而增大的字频效应,即当汉字字频每减小一个对数单位其识别时间增加约０．０７９秒;识别眼动的注视次数（ｎｕｍｂｅｒｏｆｆｉｘａｔｉｏｎｓ）也随字频减小而增多,注视时程（ｆｉｘａｔｉｏｎｄｕｒａｔｉｏｎ）基本不变;采用＂二决一＂及＂重复显示＂汉字识别实验,证实字频效应反映了识别时间与该字在识别时的先验概率的关系,从而可由实验数据计算出识别的信道容量（ＣｈａｎｎｅｌＣａｐａｃｉｔｙ）约为４２ｂｉｔｓ／ｓ。     

视觉图像辨认眼动中的Top－down信息处理

在视觉图像辨认过程中,眼球不是均匀地扫描全幅图像,而是通过一系列快速的眼球跳动来改变注视点位置,有选择地通过注视停顿来采集图象中的关键信息。通过实验对不同图像刺激时的眼动轨迹进行记录与分析,发现：（１）对于简单的几何图形,眼动注视停顿主要集中在图像中几何特征之处,亦即与周围不同的奇异点上;（２）对复杂图象刺激,眼动注视点位置决定于受试者的已有概念模型及其兴趣所在;（３）对中文单字进行辩认时,其眼动模式也是取决于受试者对该单字的知识（也即概念模型）。以上结果提示,视觉图象辨认主要是通过自上而下（ｔｏｐ－ｄｏｗｎ）的信息处理方式才完成．由中枢控制眼球运动,将注视点落到中枢决定的图形奇点上来,通过注视停顿对中枢认为的关键信息之处进行抽提,以实现辨认。这种处理方式不是只取决于输入的图像信息,也不必对目标图像的每个象素进行处理,而只需对图象中少量的关键信息部位进行重点的检测和处理,从而提高了图象信息处理的能力及效率。     

视觉图像辨认眼动中的Top－down信息处理

在视觉图像辨认过程中,眼球不是均匀地扫描全幅图像,而是通过一系列快速的眼球跳动来改变注视点位置,有选择地通过注视停顿来采集图象中的关键信息。通过实验对不同图像刺激时的眼动轨迹进行记录与分析,发现：（１）对于简单的几何图形,眼动注视停顿主要集中在图像中几何特征之处,亦即与周围不同的奇异点上;（２）对复杂图象刺激,眼动注视点位置决定于受试者的已有概念模型及其兴趣所在;（３）对中文单字进行辩认时,其眼动模式也是取决于受试者对该单字的知识（也即概念模型）。以上结果提示,视觉图象辨认主要是通过自上而下（ｔｏｐ－ｄｏｗｎ）的信息处理方式才完成．由中枢控制眼球运动,将注视点落到中枢决定的图形奇点上来,通过注视停顿对中枢认为的关键信息之处进行抽提,以实现辨认。这种处理方式不是只取决于输入的图像信息,也不必对目标图像的每个象素进行处理,而只需对图象中少量的关键信息部位进行重点的检测和处理,从而提高了图象信息处理的能力及效率。     

栉眼蚤属中华栉眼蚤亚属三新种记述及对有关问题的探讨（蚤目：…

本文记述栉眼蚤属中华栉眼蚤亚属Ｃｔｅｎｏｐｈｔｈａｌｍｕｓ（Ｓｉｎｏｃｔｅｎｏｐｈｔｈａｌｍｕｓ）Ｈｏｐｋｉｎｓ ｅｔ Ｒｏｔｈｓｃｈｉｌｄ,１９６６的三个新种：绩溪栉眼蚤,新种Ｃｔｅｎｏｐｈｔｈａｌｍｕｓ（Ｓ．）ｊｉｘｉｅｎｓｉｓ Ｌｉｅｔ Ｚｅｎｇ,ｓｐ．ｎｏｖ．,兴安栉眼蚤,新种Ｃｔｅｎｏｐｈｔｈａｌｍｕｓ（Ｓ．）ｘｉｎｇａｎｅｎｓｉｓ Ｌｉ ｅｔ Ｚｅｎｇ ｓｐ．ｎｏｖ．和信宜栉眼蚤,新     

无眼动条件下中文阅读的研究

设计了计算机控制的中文阅读材料的不同显示方式,并对各种阅读过程中的徙动波形进行记录和分析。实验结果表明,无眼动的阅读速度较正常有眼动高,分别为853字/分和640字/分。通过固定窗口显示方式和知动窗口显示方式条件下中文阅读的比较,排除了强迫阅读的因素,说明有无眼动是产生阅读速度差异的主要原因;根据以上实验结果,可得出结论,在有眼动的情况下,除了saccade抑制影响阅读和识别外,主要的因素在于高级中枢对位置信号的处理,眼动的驱动控制及运动过程影响了高级中枢对阅读内容和识别内容的解码速率。无眼动阅读的速度主要受到高级中枢解码速率和记忆的影响,而不是周边视觉系统的限制。实验结果还表明,在无眼动的情况下,周边信息对阅读不仅不起帮助作用,反而起到干扰作用。     

小脑控制不同类型眼动的神经编码机制：从小脑皮层到小脑核团

近年来许多研究发现,小脑作为运动控制的主要脑区,除参与运动控制外也与孤独症、精神分裂症、奖励相关的认知功能和社会行为有关,因此小脑相关研究越来越受到重视。研究小脑参与运动学习和运动控制的神经机制是神经科学中最重要的课题之一。眼睛运动的肌肉协调和生物运动特征比其他类型的运动更简单,这使眼动成为研究小脑在运动控制中作用的理想模型。作为收集外界信息的主要方式之一,视觉对日常生活至关重要。为确保清晰视觉,3种主要类型的眼动（眼跳、平滑追随眼动（SPEM）和注视）需受小脑的精确控制,以确保静止或移动的物体保持在视小凹的中心。异常眼动可导致视力障碍,并可作为诊断各种疾病的临床指标。因此,眼动控制研究具有重要的医学和生物学意义。虽然对小脑皮层和顶核在调节眼动中的作用有基本了解,但眼动动力学编码的确切神经机制,尤其是小脑顶核控制追随眼动和注视的神经机制仍不清楚。本综述总结了目前小脑在运动和认知等方面的主要研究问题与小脑相关研究的潜在应用价值,以及近年来有关小脑控制眼动的相关文献,并深入探讨了利用单细胞记录和线性回归模型分析小脑皮层和顶核同一神经元同时参与控制不同类型的眼动,而不同类型眼动的不同动力学参数编码原则不同。此外,基于检测微眼跳的研究结果,我们讨论了小脑顶核参与控制视觉注视的可能神经机制。最后,讨论了最近技术进步给小脑研究带来的新机遇,为今后与小脑相关的研究和脑控义肢的优化控制（例如通过单独改善运动参数优化义肢控制）提供了新思路。     

横断山地区的伏绕眼果蝇亚属及三新种(双翅目:果蝇科)

本文记述分布在中国横断山地区绕眼果蝇属伏绕眼果蝇亚属［Ａｍｉｏｔａ（Ｐｈｏｒｔｉｃａ）］的１１个物种，其中包括３个新种：不对称绕眼果蝇Ａ．（Ｐ．）ａｃｏｎｇｒｕｅｎｓｓｐ．ｎ．、突绕眼果蝇Ａ．（Ｐ．）ｐｒｏｔｒｕｓａｓｐ．ｎ．、韩氏绕眼果蝇Ａ．（Ｐ．）ｈａｎｉｓｐ．ｎ．。     

转化人胚肌腱细胞力学特性研究

探讨转化人胚腱细胞９Ｔｒａｎｓｆｏｒｍｅｄ ｈｕｍａｎ ｅｍｂｒｙｏｎｉｃ ｔｅｎｄｏｎ ｅｅｌｌｓ,ＴＨＥＴＣｓ）力学特性,以阐明在应变条件下进行细胞－支架材料复合培养时腱铁力学相容性。取人腱细胞（Ｈｕｍａｎ ｅｍｂｒｙｏｎｉｃ ｔｅｎｄｏｎ ｃｅｌｌｓ,ＨＥＴＣｓ）和ＴＨＥＴＣｓ,采用微吸管吸吮实验技术,测量单个细胞的粘生及其对聚乳酸（Ｐｏｌｙｌａｃｔｉｃ ａｃｉｄ,ＰＬＡ）和聚乳酸羟基乙酸共     

横断山地区的伏绕眼果蝇亚属及三新种

本文记述分布在中国樱花断山地区绕眼果蝇属伏绕眼果蝇亚属「Ａｍｉｏｔａ（Ｐｈｏｒｔｉｃａ）」的１１个物种,其中包括３个新种,不对称绕眼果蝇Ａ．（Ｐ．）ａｃｏｎｇｒｕｅｎｓ ｓｐ．ｎ．、突绕眼果蝇Ａ．（Ｐ．）ｐｒｏｔｒｕｓａ ｓｐ．ｎ．、韩氏绕眼果蝇Ａ．（Ｐ．）ｈａｎｉ ｓｐ．ｎ。     

中国栉眼蚤属两新亚种记述(蚤目:多毛蚤科)

根据１９８８年以来,人采自浙江省景宁,永嘉等县的标本,记述了栉眼蚤属两新亚各,即台湾栉眼蚤浙江亚种Ｃｔｅｎｏｐｈｔｈａｌｍｕｓ（Ｓｉｎｏｃｔｅｎｏｐｈｔｈａｌｍｕｓ）ｔａｉｗａｎｕｓｚｈｅｊｉａｎｇｅｎｓｉｓＬｕｅｔＱｉｕ,ｓｓｐ．ｎｏｖ和短突栉眼蚤永嘉亚种Ｃｔｅｎｏｐｈｔｈａｌｍｕｓ（Ｓｉｎｏｃｔｅｎｏｐｈｔｈａｌｍｕｓ）ｂｒｅｖｉｐｒｏｊｉｃｉｅｎｓｙｏｎｇｊｉａｅｎｓｉｓ,Ｌｕ,Ｚｈａｎｇ,     

The relationship between absolute disparity and ocular vergence

The relationship between disparity and ocular vergence was investigated under closed-loop as well as under open-loop viewing conditions. First we examined whether vergence responded similarly to disparity presented under open-loop and closed-loop conditions. Similar response were observed in both conditions. The direct relationship between disparity and vergence was examined by presenting constant disparities between 0.2° and 4° under open-loop viewing conditions. Such vergence responses are described as the outputs of first-order low-pass filters with different filter characteristics for each amplitude of disparity. By analyzing the latency of vergence responses induced by constant disparities with help of the transfer function of disparitycontrolled vergence, the time delay of disparity processing in the vergence loop was estimated. We suggested that the time delay was approximately between 80 and 120 ms instead of 160 ms as is generally assumed. The relationship between the rate of disparity change and vergence was examined by comparing responses to ramp and stepwise changes in target vergence. From the similar responses to ramp and staircase changes in disparity we concluded that vergence is not sensitive to the velocity of target vergence as such. On the basis of these findings we developed a model of disparity-controlled vergence. In this model disparity is processed through several parallel, imperfect integrators with slightly different low-pass filter characteristics, each of them susceptible to a limited range of disparities. Gains as well as phase lags of vergence responses to sinusoidal disparities are accurately simulated by this model. As a consequence of the limited working range of the low-pass filters, the model correctly simulates the alterations of fast and slow phases in response to step and ramps of target vergence, which are characteristic of real vergence responses.     

Direct extraction of curvature-based metric shape from stereo by view-modulated receptive fields

Any computation of metric surface structure from horizontal disparities depends on the viewing geometry, and analysing this dependence allows us to narrow down the choice of viable schemes. For example, all depth-based or slant-based schemes (i.e. nearly all existing models) are found to be unrealistically sensitive to natural errors in vergence. Curvature-based schemes avoid these problems and require only moderate, more robust view-dependent corrections to yield local object shape, without any depth coding. This fits the fact that humans are strikingly insensitive to global depth but accurate in discriminating surface curvature. The latter also excludes coding only affine structure. In view of new adaptation results, our goal becomes to directly extract retinotopic fields of metric surface curvatures (i.e. avoiding intermediate disparity curvature).To find a robust neural realisation, we combine new exact analysis with basic neural and psychophysical constraints. Systematic, step-by-step ‘design’ leads to neural operators which employ a novel family of ‘dynamic’ receptive fields (RFs), tuned to specific (bi-)local disparity structure. The required RF family is dictated by the non-Euclidean geometry that we identify as inherent in cyclopean vision. The dynamic RF-subfield patterns are controlled via gain modulation by binocular vergence and version, and parameterised by a cell-specific tuning to slant. Our full characterisation of the neural operators invites a range of new neurophysiological tests. Regarding shape perception, the model inverts widely accepted interpretations: It predicts the various types of errors that have often been mistaken for evidence against metric shape extraction.     

Where Do the Eyes Really Go in the Hollow-Face Illusion?

The hollow-face illusion refers to the finding that people typically perceive a concave (hollow) mask as being convex, despite the presence of binocular disparity cues that indicate the contrary. Unlike other illusions of depth, recent research has suggested that the eyes tend to converge at perceived, rather than actual, depths. However, technical and methodological limitations prevented one from knowing whether disparity cues may still have influenced vergence. In the current study, we presented participants with virtual normal or hollow masks and asked them to fixate the tip of the face's nose until they had indicated whether they perceived it as pointing towards or away from them. The results showed that the direction of vergence was indeed determined by perceived depth, although vergence responses were both somewhat delayed and of smaller amplitude (by a factor of about 0.5) for concave than convex masks. These findings demonstrate how perceived depth can override disparity cues when it comes to vergence, albeit not entirely.     

Effects of Prism Eyeglasses on Objective and Subjective Fixation Disparity

In optometry of binocular vision, the question may arise whether prisms should be included in eyeglasses to compensate an oculomotor and/or sensory imbalance between the two eyes. The corresponding measures of objective and subjective fixation disparity may be reduced by the prisms, or the adaptability of the binocular vergence system may diminish effects of the prisms over time. This study investigates effects of wearing prisms constantly for about 5 weeks in daily life. Two groups of 12 participants received eyeglasses with prisms having either a base-in direction or a base-out direction with an amount up to 8 prism diopters. Prisms were prescribed based on clinical fixation disparity test plates at 6 m. Two dependent variables were used: (1) subjective fixation disparity was indicated by a perceived offset of dichoptic nonius lines that were superimposed on the fusion stimuli and (2) objective fixation disparity was measured with a video based eye tracker relative to monocular calibration. Stimuli were presented at 6 m and included either central or more peripheral fusion stimuli. Repeated measurements were made without the prisms and with the prisms after about 5 weeks of wearing these prisms. Objective and subjective fixation disparity were correlated, but the type of fusion stimulus and the direction of the required prism may play a role. The prisms did not reduce the fixation disparity to zero, but induced significant changes in fixation disparity with large effect sizes. Participants receiving base-out prisms showed hypothesized effects, which were concurrent in both types of fixation disparity. In participants receiving base-in prisms, the individual effects of subjective and objective effects were negatively correlated: the larger the subjective (sensory) effect, the smaller the objective (motor) effect. This response pattern was related to the vergence adaptability, i.e. the individual fusional vergence reserves.     

Ocular vergence under natural conditions. II. Gaze shifts between real targets differing in distance and direction

Horizontal binocular eye movements of three subjects were recorded with the scleral sensor coil--revolving magnetic field technique during voluntary shifts of gaze between pairs of stationary, real, continuously visible targets. The target pairs were located either along the median plane (requiring symmetrical vergence), or on either side of the median plane (requiring asymmetrical vergence). Symmetrical vergence was primarily smooth, but it was often assisted by small, disjunctive saccades. Peak vergence speeds were very high; they increased from about 50 degrees s-1 for vergence changes of 5 degrees to between 150 and 200 degrees s-1 for vergence changes of 34 degrees. Differences between convergence and divergence were idiosyncratic. Asymmetrical vergence, requiring a vergence of 11 degrees combined with a version of 45 degrees, was largely saccadic. Unequal saccades mediated virtually all (95%) of the vergence required in the divergent direction, whereas 75% of the vergence required in the convergent direction was mediated by unequal saccades, with the remaining convergence mediated by smooth vergence, following completion of the saccades. Peak divergence speeds during these saccades were very high (180 degrees s-1 for a change of vergence of 11 degrees); much faster than the smooth, symmetrical vergence change of comparable size (14 degrees). Peak convergent saccadic speeds were about 20% lower. This difference in peak speed was caused by an initial, transient divergence, observed at the beginning of all horizontal saccades. The waveform of disjunctive saccades did not have the same shape as the waveform of conjugate saccades of similar size. The smaller saccade of the disjunctive pair was stretched out in time so as to have the same duration as its larger, companion saccade. These results permitted the conclusion that the subsystems controlling saccades and vergence are not independent. Vergence responses were relatively slow and incomplete with monocular viewing, which excluded disparity as a cue. Monocularly stimulated vergence decreased as a function of the increasing presbyopia of our three subjects. Subjects were able to generate some vergence in darkness towards previously seen and remembered targets. Such responses, however, were slow, irregular and evanescent. In conclusion, vergence shifts between targets, which provided all natural cues to distance, were fast and accurate; they appeared adequate to provide effective binocular vision under natural conditions. This result could not have been expected on the basis of previous observations, all of which had been made with severely reduced cues to depth.(ABSTRACT TRUNCATED AT 400 WORDS)     

立体视锐度的测量

视差只在一定大小范围内才能产生体视感觉。对５名体视感觉正常者和一名体视感觉欠缺者做心理物理试验并记录视觉诱发电位（ＶＥＰ）。结论如下：（１）交叉视差产生体视感觉的视差下限阈值约为２５秒;非交叉视差产生体视感觉的视差下限阈值约为３５秒。（２）改变视差大小的方法不同对这个阈值有影响。视差由大到小改变比由小到大改变,这个视差下限阈值要小,两者差别约为１０秒至２０秒。（３）体视欠缺者产生体视感觉的视差下限阈值约为６０秒。（４）使用不同形式的立体图对这个阈值不同,对于随机点立体图对,产生体视感觉下限阈值约为６０秒。（５）当视差大于１２０秒时的ＶＥＰ呈现规律变化。（６）体视欠缺者的ＶＥＰ与正常者比较呈现较大的差别。     

Evidence for implication of primate area V1 in neural 3-D spatial localization processing.

We investigated the neural mechanisms underlying visual localization in 3-D space in area V1 of behaving monkeys. Three different sources of information, retinal disparity, viewing distance and gaze direction, that participate in these neural mechanisms are being reviewed. The way they interact with each other is studied by combining retinal and extraretinal signals. Interactions between retinal disparity and viewing distance have been shown in foveal V1; we have observed a strong modulation of the spontaneous activity and of the visual response of most V1 cells that was highly correlated with the vergence angle. As a consequence of these gain effects, neural horizontal disparity coding is favoured or refined for particular distances of fixation. Changing the gaze direction in the fronto-parallel plane also produces strong gains in the visual response of half of the cells in foveal V1. Cells tested for horizontal disparity and orientation selectivities show gain effects that occur coherently for the same spatial coordinates of the eyes. Shifts in preferred disparity also occurred in several neurons. Cells tested in calcarine V1 at retinal eccentricities larger than 10 degrees , show that horizontal disparity is encoded at least up to 20 degrees around both the horizontal and vertical meridians. At these large retinal eccentricities we found that vertical disparity is also encoded with tuning profiles similar to those of horizontal disparity coding. Combinations of horizontal and vertical disparity signals show that most cells encode both properties. In fact the expression of horizontal disparity coding depends on the vertical disparity signals that produce strong gain effects and frequent changes in peak selectivities. We conclude that the vertical disparity signal and the eye position signal serve to disambiguate the horizontal disparity signal to provide information on 3-D spatial coordinates in terms of distance, gaze direction and retinal eccentricity. We suggest that the relative weight among these different signals is the determining factor involved in the neural processing that gives information on 3-D spatial localization.     

Dyslexic children are confronted with unstable binocular fixation while reading

Reading requires three-dimensional motor control: saccades bring the eyes from left to right, fixating word after word; and oblique saccades bring the eyes to the next line of the text. The angle of vergence of the two optic axes should be adjusted to the depth of the book or screen and--most importantly--should be maintained in a sustained manner during saccades and fixations. Maintenance of vergence is important as it is a prerequisite for a single clear image of each word to be projected onto the fovea of the eyes. Deficits in the binocular control of saccades and of vergence in dyslexics have been reported previously but only for tasks using single targets. This study examines saccades and vergence control during real text reading. Thirteen dyslexic and seven non-dyslexic children read the French text "L'Allouette" in two viewing distances (40 cm vs. 100 cm), while binocular eye movements were measured with the Chronos Eye-tracking system. We found that the binocular yoking of reading saccades was poor in dyslexic children (relative to non-dyslexics) resulting in vergence errors; their disconjugate drift during fixations was not correlated with the disconjugacy during their saccades, causing considerable variability of vergence angle from fixation to fixation. Due to such poor oculomotor adjustments during reading, the overall fixation disparity was larger for dyslexic children, putting larger demand on their sensory fusion processes. Moreover, for dyslexics the standard deviation of fixation disparity was larger particularly when reading at near distance. We conclude that besides documented phoneme processing disorders, visual/ocular motor imperfections may exist in dyslexics that lead to fixation instability and thus, to instability of the letters or words during reading; such instability may perturb fusional processes and might--in part--complicate letter/word identification.     

视差检测：简单细胞、复杂细胞及能量模型

立体视觉信息的处理在于皮层双眼性细胞的活动.皮层中简单细胞对视差的编码方式被认为有两种：位置差（position shift）和相位差（phase shift）,但简单细胞并不适合作为视差检测器.对一些复杂细胞的视差响应特性的生理研究,发现复杂细胞是一种比较适合的视差检测器.模型的研究提出基于这类简单细胞的复杂细胞能量模型,可以很好的检测视差,并可以较好的解释一些生理现象.