图形简单几何特征的分辨及其相关错觉的定量研究

本实验用定量的心理物理测量方法,研究了在亮度对比与等亮度颜色对比的条件下,受试者分辨图形简单几何特征的能力以及与这些图形特征有关的错觉效应（Ｚｏｅｌｌｎｅｒ错觉、Ｍｕｌｌｅｒ－Ｌｙｅｒ错觉、Ｐｏｎｚｏ错觉和Ｄｅｌｂｏｅｕｆ错觉）。实验结果表明：受试者在亮度对比与颜色对比的条件下对线段平行度,线段长度与图形面积的分辨能力相同,与这些几何特征有关的错觉幅度也没有显著差异。但是,在等亮度颜色对比条件下,     

猫视皮层17,18区神经元对错觉轮廓的反应

研究了轻度麻醉下猫视皮层17, 18区细胞对错觉轮廓刺激的反应特性, 比较了对错觉轮廓有明显反应的细胞对真实轮廓和错觉轮廓刺激的感受野特性的异同. 共记录了猫视皮层17, 18区200个方位/方向选择性细胞, 其中有42%的细胞是错觉轮廓反应细胞. 将这些细胞对真实轮廓和错觉轮廓的反应进行比较, 尽管错觉轮廓反应细胞对移动光棒和错觉轮廓光棒的方位/方向调制曲线十分相似, 但对移动错觉棒和移动光棒的反应模式(潜伏期和反应时程)不同. 对由光栅组成的错觉轮廓而言, 细胞的反应大小与组成光栅的相位无关, 并且细胞对组成错觉轮廓光栅的最优空间频率比对普通移动光栅的最优空间频率要高得多, 说明细胞确实是对轮廓本身反应, 而不是对组成轮廓的光栅的末端反应. 某些速度调制类型的细胞对移动错觉棒反应的最优速度比对移动光棒的最优速度要低得多. 进一步验证了猫视皮层17, 18区部分细胞能对错觉轮廓反应, 并且观察到这些细胞对错觉轮廓和真实轮廓有不同的感受野反应特性, 提示视觉系统对两种刺激图形的检测机制可能存在着差异.     

同心圆感受野去抑制特性的数学模拟

以感受野外周区内各亚区之间的抑制性相互作用为基础,提出了一个能描述视网膜神经节细胞传输特性的数学模型,此模型能很好地解释传统感受野外大范围去抑制区产生的机制。当用来处理亮度对比边缘时,它既能很好地增强边缘对比,又可有效地提升被传统感受野中心／外周拮抗机制所滤除了的区域亮度对比和亮度梯度信息。本文也用不同空间频率的光栅和真实图像检验了模型的空间频率传递特性,并与其它模型进行了比较。     

视觉图形诱发的瞳孔反应

以图形变化刺激进行瞳孔反应研究,实验表明：（１）空间平均亮度守恒的光栅或棋盘格图形翻转能激发起瞳孔反应,为瞬态收缩波形,与ｐｕｐｉｌｌａｒｙ ｅｓｃａｐｅ相似;（２）光栅或棋盘格的空间频率的变化也能引起瞳孔反应,且反应幅度随空间频率差别增大而变大;（３）从均匀亮背景变化到棋盘格图形或者从棋盘格图形变化到黑暗背景,虽然不存在任何局部亮度增强,皆能引起瞳孔反应。实验结果明确证明了人的瞳孔反应系统除接收     

不同时间频率光栅刺激引起的视觉诱发电位(VEP)方位效应的差异

以人视觉诱发电位(VEP)反应为指标,在不同的时间频率下测定了 VEP 对方波光栅刺激的反应幅度与光栅方位的关系。当光栅方位固定时,光栅闪烁的时间频率不同,VEP 反应的波形、潜伏期和反应频率差别很大,但其反应幅度均呈现方位选择性。当光栅的时间频率为9.1Hz时,光栅为垂直和水平方位时引起的 VEP 反应幅度比倾斜方位时都大,对任何光栅方位,VEP反应幅度与光栅对比度的对数呈线性关系;与此相反,当光栅时间频率为0.4Hz 时,光栅为倾斜方位时引起的 VEP 反应幅度比垂直和水平方位时更大。     

相岭山系大熊猫的营养和能量对策

１９９４年至１９９６年,在冕宁县冶勒自然保护区设点,对相岭山系大熊猫的营养和能量利用进行了研究。研究结果表明,该山系的大熊猫不仅能消化食物中的粗蛋白和粗脂肪,也能部分消化半纤维素。当以秆叶为食时,其粗蛋白、粗脂肪和半纤维素消化率分别为６１．５％、５０．３％和２３．３％;而当以竹笋为食时,消化率分别为７１．９％、６１．５％和２９．６％;对竹笋中营养养物质的利用率高于秆叶。由于不同季工节食物组成、干物     

自由飞行蜜蜂对静止目标形状和颜色的综合识别能力

研究了蜜蜂对相同颜色和不同颜色目标图对的形状以及颜色的综合识别能力实验过程中,蜜蜂始终处于自由飞行状态.做为刺激目标使用的图对分别有相同颜色不同几何形状、相同颜色不同拓扑结构和不同颜色几何形状三组.主要结果有三点:(1)在相同颜色的条件下,蜜蜂可以分辨出图形的几何形状,并且识别能力与图对的相似程度成反比(2)在刺激图形为环形时,蜜蜂对图形平均亮度敏感;在平均亮度相同的情况下,对环形细节变和尺寸大小不敏感.(3)在不同颜色不同几何形状的刺激条件下.蜜蜂视觉信息加工过程中颜色因素会抑制几何形状因素而起主要作用.这三个结果可以视为深入研究颜色加工通道和几何形状加工通道之间内在关系的基础.     

大鼠背根节神经元后超极化中Ca~(2 )激活K~ 电流的蜂毒明肽敏感成分I_(AHP)

为了明确大鼠背根节（DRG）神经元中存在慢的Ca2 激活K 电流成分,本实验在新鲜分散的DRG神经元胞体上,采用全细胞电压箝技术,给予DRG神经元一定强度的去极化刺激,记录刺激结束后30ms时的尾电流幅度。结果发现：（1）随着去极化时间从1ms延长至180ms时,尾电流幅度由9．3±2．8pA逐渐增大至64.1±3．4pA（P＜0．001）;（2）当去极化结束后的复极化电位降低时,尾电流幅度先逐渐下降到零,然后改变方向,逆转电位约为-63mV;（3）细胞外施加500μmol／LCd2 或细胞内液中施加11mmol／LEGTA时尾电流明显减小甚至完全消失;（4）尾电流中慢成分的幅度在细胞外给与200nmol／L蜂毒明肽后,减小了约26.32±3。9％（P＜0。01）;（5）细胞外施加10mmol／LTEA,可明显降低尾电流中的快成分。结果提示,在DRG神经元启超极化中存在Ca2 激活K 电流的蜂毒明肽敏感成分──IAHP。     

背景光对图形视网膜电图空间调谐特性的影响

本工作应用背景光压抑闪光视网膜电图(FERG),考察对图形视网膜电图(PERG)的空间调谐特性的影响,并与无背景光时的结果进行比较。背景光使全屏幕闪光诱发的FERG基本压抑。在这种条件下,同屏幕的图形刺激所诱发的PERG的振幅显示一定的低空间频率衰减(LSFA)。FFT分析表明,当时间频率为3.91Hz时,PERG的二次谐波呈现十分明显的LS-FA,与无背景光时的结果吻合得很好;当时间频率为7.81Hz时,也表现出LSFA,而无背景光时则缺如。这些结果表明,无背景光时记录的PERG振幅在低空间频率区偏高确实是由于混杂有亮度特异性成分—FERG。但是,PERG振幅所显示的LSFA仍不如二次谐波那么明显,这可能是因为FERG中存在的非线性成分未为背景光所完全压抑,仍然混杂在低频区的PERG反应中。     

甜菊含甙量的变异及R—A型良种的选育

从甜味成分种类及含量的不同,研究甜菊实生群体和单株无性系的变化,从中选育优质甜味成分含量高的良种。主要结果：（１）在实生群体中,丰产株型（圆纺锤形株）占７．３％,其中,优质甜味成分Ｒ－Ａ含量超过Ｓｔ含量的Ｒ－Ａ型株占１０．９６％,它们的Ｒ－Ａ含量变幅为３．３－１２．０％。（２）Ｒ－Ａ型良种Ｊ－２单株无生系在繁殖达２０００万株时,叶片大小和含甙量均存在极显著差异,Ｒ－Ａ含量变幅为４．５－１２．２％。     

Dissociation of color and figure-ground effects in the watercolor illusion

Two phenomena can be observed in the watercolor illusion: illusory color spreading and figure-ground organization. We performed experiments to determine whether the figure-ground effect is a consequence of the color illusion or due to an independent mechanism. Subjects were tested with displays consisting of six adjacent compartments--three that generated the illusion alternating with three that served for comparison. In a first set of experiments, the illusory color was measured by finding the matching physical color in the alternate compartments. Figureness (probability of 'figure' responses, 2AFC) of the watercolor compartments was then determined with and without the matching color in the alternate compartments. The color match reduced figureness, but did not abolish it. There was a range of colors in which the watercolor compartments dominated as figures over the alternate compartments although the latter appeared more saturated in color. In another experiment, the effect of tinting alternate compartments was measured in displays without watercolor illusion. Figureness increased with color contrast, but its value at the equivalent contrast fell short of the figureness value obtained for the watercolor pattern. Thus, in both experiments, figureness produced by the watercolor pattern was stronger than expected from the color effect, suggesting independent mechanisms. Considering the neurophysiology, we propose that the color illusion follows from the principles of representation of surface color in the visual cortex, while the figure-ground effect results from two mechanisms of border ownership assignment, one that is sensitive to asymmetric shape of edge profile, the other to consistency of color borders.     

Illusory boundary interpolation from local association field

We previously showed that interpolation between vertically misaligned luminance edges of same polarity of contrast is preferred to that between co-linear edges of opposite polarity of contrast, although it results in illusory tilt (Roncato and Casco, 2003). We here analyze the spatial conditions that produce this illusory binding of vertically misaligned edges of light and dark tiles, alternated in a row, and in counterphase with those in the rows above and below. We find that, independently of scale and number of tiles in a row, the illusion is perceived when the vertical misalignment of more than three tiles is smaller than or equal to 9' and the horizontal separation between co-linear edges is smaller than or equal to 13'. These short distances suggest that the underlying mechanism is local. Both our phenomenological and psychophysical results support the notion of a local short-range association field, selective to contrast polarity, which produces a binding solution different from that of a phase-independent long-range mechanism. We suggest that the occurrence of the illusion at local-level is a result of the activation, within a local short-range association field, of units with orientation different from that stimulated by the physical edges. These units are not inhibited when they are close, iso-oriented and co-linear, and the misaligned edges from which they propagate have the same contrast polarity. We found that horizontal and vertical spatial limits for the interpolation covary but not such that their ratio is fixed, indicating that the two edges can be connected by projections having a relatively wide range of orientations.     

SAMPLE SIZE ESTIMATION FOR GENE ACTION ANALYSIS BY USING ORTHOGONAL CONTRAST

IIntroductionTheuseofrestrlctlonfragmentlengthpolymorphism（RFLP）markershasgreatlyslmpllfledthegeneticanalysisofquantitativetraits,providingareliableandextensiveframeworkofquantltatlvemarkerstowhichquantltatlyetyaitIOCI（QTL）clnhilinked［‘］．TodetectthelinkagebetwwenRFLPmarkersandPhenotyPlcvariationsoh－served,generallinearmodelofanalysisofvariance（ANOVA）hasbeenextensivelyusedL‘zJ．ByusingF、populations,thecompletegeneticInformation,thatIs,thethreegenotypesofageneticfact…     

朝向和对比度同时快速变化条件下的分辨能力

在自然的视觉中,投射到视网膜上的视觉图像总是在不停地变化,而人类的感知系统依然可以准确高效地识别物体.因此,人类的感知系统有相应的快速处理机制以应对这种动态变化．然而,前人的实验都是在相对稳定的刺激条件下研究人类被试的感知系统对一个刺激参数的反应,比如在固定对比度下测试朝向分辨能力,或在固定朝向测定对比度分辨能力,而朝向和对比度同时变化时,人类对这两个参数的分辨能力仍然缺乏研究．因此,在本实验中,我们使用朝向和对比度同时变化的刺激,研究了人类被试对朝向和对比度的分辨能力．结果表明,在这种动态变化的条件下,被试对朝向和对比度的分辨阈值都有显著性的降低．而且,朝向分辨阈值降低的幅度与在固定对比度参数条件下的分辨阈值成负相关,即在固定对比度条件下朝向分辨阈值较高的被试,在朝向和对比度同时变化条件下,其朝向分辨阈值降低的幅度相对要大,朝向分辨能力也就相对地提高更大．对比度分辨能力也呈现同样的规律．这些结果说明,朝向和对比度的同时变化提高了被试对朝向和对比度的分辨能力,一个参数变化时其分辨能力越低的被试,两个参数变化时其分辨能力提高的幅度就越大．揭示了视觉系统处理这种多刺激参量信息变化的能力和机制,对人类视觉系统在真实的视觉过程中如何处理朝向和对比度信息提供了认识．     

The use of the cancellation technique to quantify the Hermann grid illusion

When observers view a grid of mid-gray lines superimposed on a black background, they report seeing illusory dark gray smudges at the grid intersections, an effect known as the Hermann grid illusion. The strength of the illusion is often measured using the cancellation technique: A white disk is placed over one of these intersections and the luminance of the disk is reduced until the disk disappears. Its luminance at this point, i.e., the disk's detection threshold, is taken to be a measure of the strength of the illusion. Our experiments showed that some distortions of the Hermann grid, which were sufficient to completely disrupt the illusion, did not reduce the disk's detection threshold. This showed that the cancellation technique is not a valid method for measuring the strength of the Hermann grid illusion. Those studies that attempted to use this technique inadvertently studied a different effect known as the blanking phenomenon. We conclude by presenting an explanation for the latter effect.     

Simulation of Neuronal Responses Defining Depth Order and Contrast Polarity at Illusory Contours in Monkey Area V2

Neurophysiological, brain imaging, and perceptual studies in animals and humans suggest that illusory (occluding) contours are represented at an early level of visual cortical processing. Comparatively little is known about the mechanisms defining the depth order and the brightness illusion associated with such contours. Baumann et al. (1997) found neurons in area V2 of the alert monkey that signaled not only illusory contours but also the figure-ground direction that human observers perceive at such contours. The majority of these neurons showed this property independent stimulus contrast; a small minority preferred a certain combination of figure-ground direction and contrast polarity at these contours. In this article, we simulate the responses of these neurons by means of a grouping mechanism that uses occlusion cues (line-ends, corners) to define figure-ground direction and contrast polarity at such contours.     

PATCHY CONTRAST OF HABITAT AFFECTS INTRACLONAL DIVISION OF LABOR OF POTENTILLA ANSERINA

 相互连接的克隆植物分株分别处于资源互补性的不同斑块时, 将可能发生形态结构的特化, 以更有效地吸收利用所处斑块中丰富的资源, 形成分株的功能分化, 即克隆内分工。生境的斑块对比度, 作为资源或环境异质性的主要素, 在一定程度上决定克隆内分工的发生状况。该文以鹅绒委陵菜(Potentilla anserina)为材料, 在自然条件下将多组分株对置于不同的斑块对比度处理下, 比较了它们克隆内分工的发生状态, 试图发现分工与斑块对比度的关系, 同时考察在克隆分工过程中分株的可塑性变化及其与分工的关系。该实验的理论假设是: 分株发生分工的程度与分株所处斑块的资源对比度成正相关。研究结果表明, 鹅绒委陵菜分株的高度和叶面积对局部光照环境产生强烈的可塑性反应, 反应的结果是增加了对匮乏的光资源的获取。从分株根冠比和我们提出的分工指数来看, 分工的程度在一定的斑块对比度范围内随斑块对比度的增强而增强, 但到达一个最大值后又迅速降低。鹅绒委陵菜分株之间的分工和结构特化往往滞后于分株对所处局部环境的适应性可塑性变化, 而后者往往在分株之间具有独立性和局部特征。克隆内分工主要依赖于生物量分配的调节而实现, 其发生状态都是分株系统在分工收益、分工代价与分工风险之间权衡的结果, 而这种结果在很大程度上取决于分株所处的斑块对比度。     

Conjunctions of colour, luminance and orientation: the role of colour and luminance contrast on saliency and proximity grouping in texture segregation

To examine whether perceptual grouping on the basis of orientation can be performed simultaneously with or only subsequently to grouping according to colour or luminance, we tested whether subjects are able to segregate arrays of texture elements that differ from surrounding elements by conjunctions of either (i) colour and orientation, or (ii) luminance contrast and orientation, or (iii) luminance contrast polarity and orientation. Subjects were able to use conjunctions between luminance and orientation for segregation but not conjunctions between colour or contrast polarity and orientation. Our results suggest that (i) in agreement with earlier findings, there seem to exist no specific conjunction detectors for colour and orientation or contrast polarity and orientation, and (ii) when orientation defined textures are to be distinguished by virtue of differences in luminance, colour, or contrast polarity, luminance provides a much stronger cue than colour or contrast polarity for saliency-based orientation grouping.     

Lighting, backlighting and watercolor illusions and the laws of figurality

We report some novel 'lighting' and 'backlighting' effects in plane figures similar to those which induce the 'watercolor illusion', that is, figures made with outlines composed of juxtaposed parallel lines varying in brightness and chromatic color. These new effects show 'illumination' as an emergent percept, and show how arrangements of 'dark and light' along the boundaries of various plane figures model the volume and strengthen the illusion of depth. To account for these various effects we propose several phenomenological 'laws of figurality' to add to the Gestalt laws of organization and figure-ground segregation. We offer a set of meta-laws which are speculative but which serve to integrate and organize the phenomenological laws. These laws indicate how luminance gradient profiles across boundary contours define both the 3D appearance of figures and the properties of the light reflected from their volumetric shapes.