A TAS1R receptor-based explanation of sweet 'water-taste'

'Water-tastes' are gustatory after-impressions elicited by water following the removal of a chemical solution from the mouth, akin to colour after-images appearing on 'white' paper after fixation on coloured images. Unlike colour after-images, gustatory after-effects are poorly understood. One theory posits that 'water-tastes' are adaptation phenomena, in which adaptation to one taste solution causes the water presented subsequently to act as a taste stimulus. An alternative hypothesis is that removal of the stimulus upon rinsing generates a receptor-based, positive, off-response in taste-receptor cells, ultimately inducing a gustatory perception. Here we show that a sweet 'water-taste' is elicited when sweet-taste inhibitors are rinsed away. Responses of cultured cells expressing the human sweetener receptor directly parallel the psychophysical responses-water rinses remove the inhibitor from the heteromeric sweetener receptor TAS1R2-TAS1R3, which activates cells and results in the perception of strong sweetness from pure water. This 'rebound' activity occurs when equilibrium forces on the two-state allosteric sweet receptors result in their coordinated shift to the activated state upon being released from inhibition by rinsing.     

利用基于人耳模型的声像图分析乐音的协和度

引入了人耳模型并计算其声像图来分析简单乐音的协和度．人耳模型模拟了人的心理和生理过程，通过该方法来寻找乐音的协和度与听觉客观机制之间的内在联系，使得主观感受和客观分析之间的联系更紧密．研究发现，稳定的和声音程具有稳定的声像图；声像图可以有效地判别简单乐音的协和程度，即简单乐音的协和度可通过声像图中纵向排列“整齐”的明亮条纹的数目以及相邻两明亮条纹间各阶分叉结构的数目来表征．     

Parallel processing of motion and colour information

When the two eyes are confronted with sufficiently different versions of the visual environment, one or the other eye dominates perception in alternation. A similar situation may be created in the laboratory by presenting images to the left and right eyes which differ in orientation or colour. Although perception is dominated by one eye during rivalry, there are a number of instances in which visual processes nevertheless continue to integrate information from the suppressed eye. For example the interocular transfer of the motion after-effect is undiminished when induced during binocular rivalry. Thus motion information processing may occur in parallel with the rivalry process. Here we describe a novel example in which the visual system simultaneously exhibits binocular rivalry and vision that integrates signals from both eyes. This apparent contradiction is resolved by postulating parallel visual processes devoted to the analyses of colour and motion information. Counterphased gratings are viewed dichoptically such that for one eye the grating is composed of alternating yellow and black stripes (luminance) while for the other it is composed of alternating red and green stripes (chrominance). When the gratings are fused, a moving grating is perceived. A consistent direction of motion can only be achieved if left and right monocular signals are integrated by the nervous system. Yet the apparent colour of the binocular percept alternates between red-green and yellow-black. These observations demonstrate the segregation of processing by the early motion system from that affording the perception of colour. Although, in this stimulus, colour information in itself can play no part in the cyclopean perception of motion direction, colour is carried along perceptually (filled in) by the moving pattern which is integrated from both eyes.     

听力训练对特定听觉辨识能力的影响

对一组无专业背景的受训者进行了由13个单元组成的声频工程综合听力训练课程,训练每周2次,持续了两个月。在训练前后对这组受训者的听力级、噪声中对纯音的辨识能力、频率分辨力等特定指标进行了测量。训练前后的数据对比分析表明,综合听力训练对特定听辨能力的提升有正迁移作用。     

Perception of three-dimensional shape influences colour perception through mutual illumination

Objects in the natural world possess different visual attributes, including shape, colour, surface texture and motion. Previous perceptual studies have assumed that the brain analyses the colour of a surface independently of its three-dimensional shape and viewing geometry, although there are neural connections between colour and two-dimensional form processing early in the visual pathway. Here we show that colour perception is strongly influenced by three-dimensional shape perception in a novel, chromatic version of the Mach Card--a concave folded card with one side made of magenta paper and the other of white paper. The light reflected from the magenta paper casts a pinkish glow on the white side. The perceived colour of the white side changes from pale pink to deep magenta when the perceived shape of the card flips from concave to convex. The effect demonstrates that the human visual system incorporates knowledge of mutual illumination-the physics of light reflection between surfaces--at an early stage in colour perception.     

从叙述学视野剖析《等待野蛮人》

库切是当代世界文坛上一位对文学创作有着独到感悟和见解的小说家。在其最具争议的《等待野蛮人》中，他寓言般的写作方式不是直接诉诸说教，使得读者可以将其放在不同的语境下加以解读。结合叙事学理论，探讨叙事视角，叙事聚焦，叙事语气如何推动对此小说主题的理解。     

师范院校英语专业学生对调核调型的感知与理解

基于Halliday（1967）提出的英语语调三重系统-语调短语划分（Tonality）、调核位置确定（Tonicity）、调型（Tone）,本研究选择其中的一个方面-调型（Tone）为切入点,考察了师范院校英语专业学生对调核调型的感知及理解情况。结果表明：师范院校英语专业学生能够较好的感知到对比组中两个句子调核调型的不同,但不能较好地理解由于调核调型不同而引起的两个句子在意义上的不同。尤其对由让步状语从句和时间状语从句构成的对比组,由让步状语从句和条件状语从句构成的对比组的理解较差。本研究启示我们在今后的英语语调教学中更要注重语调的交际意义。     

基于时域模型分析谐波复合音的音高感知机制

为了探讨中等次数的谐波复合音是否依赖于时间精细结构信息进行音高感知, 测量了谐波复合音的基频辨别阈。目标复合音可以单独存在, 或者和掩蔽复合音同时存在。二者经过相同的带通滤波区域, 具有不同的相位组合和基频差异。结果表明: 相位组合对音高感知没有显著影响; 滤波区域和基频差异对音高感知具有显著影响。采用时域模型分析发现, 中等次数的谐波复合音可能依赖于时间精细结构信息获得较好的音高感知结果。研究结果能帮助建立复杂声音场景下的音高感知机制。     

A spatially organized representation of colour in macaque cortical area V2

Neurons responding selectively to different colours have been found in various cortical areas in macaque monkeys; however, little is known about whether and how the representation of colour is spatially organized in any cortical area. Cortical area V2 contains modules that respond preferentially to chromatic modulation, which are located in thin cytochrome oxidase stripes. Here we show that within and beyond these modules, gratings of different colours produce activations that peak at different locations. Optical recording of intrinsic signals revealed that the peak regions of the responses to different colours were spatially organized in the same order as colour stimuli are arranged in the DIN (German standard colour chart) colour system. Nearby regions represented colours of a similar hue. We found that the set of colour-specific regions formed 0.07-0.32-mm-wide and approximately 1.3-mm long bands that varied in shape from linear to nearly circular. Our finding suggests that thin stripes in V2 contain functional maps where the colour of a stimulus is represented by the location of its response activation peak.     

汉语耳语音库的建立与听觉实验研究

耳语音的识别和转换是个全新的课题,可应用于公共场合下的通讯和公安司法工作的某些特殊需要等方面.首先建立了一个包含1172个字和98个近音词的单人女声的汉语耳语音库.通过对两个听觉测试实验数据的统计分析,研究了人耳对汉语耳语音字和近音词声调的辨认率特征,得出人耳对孤立字四个声调的辨认率由高到低的排序为三声>四声>二声>一声.同时也得出人耳对词声调的辨认能力比字要强得多.幅值包络和音长这两个特征参量能够反映出汉语耳语音声调的特性,基于此参数对汉语耳语音字进行声调识别实验,其声调识别率已达到了人耳的平均辨认率,为连续耳语音声调识别研究打下了基础.     

Serial and parallel processing of visual feature conjunctions

Treisman and others have reported that the visual search for a target distinguished along a single stimulus dimension (for example, colour or shape) is conducted in parallel, whereas the search for an item defined by the conjunction of two stimulus dimensions is conducted serially. For a single dimension the target 'pops out' and the search time is independent of the number of irrelevant items in the set. For conjunctions, the search time increases as the set becomes larger. Thus, it seems that the visual system is incapable of conducting a parallel search over two stimulus dimensions simultaneously. Here we extend this conclusion for the conjunction of motion and colour, showing that it requires a serial search. We also report two exceptions: if one of the dimensions in a conjunctive search is stereoscopic disparity, a second dimension of either colour or motion can be searched in parallel.     

基于Gamma tone滤波和PCNN的说话人识别

为了更好地提取说话人的特征,对语音进行滤波的预处理。Gamma tone滤波器可以很好模拟基底膜滤波器的形状,因此本文采用作为标准耳蜗听觉滤波器的Gamma tone滤波器对语谱图进行滤波,再通过脉冲耦合神经网络来提取说话人特征进行分析。仿真结果表明,由该方法得到的说话人的熵序列与自身熵序列的欧氏距离较未经过Gamma tone滤波的小,提高了识别率。     

Segregation of pathways leading from area V2 to areas V4 and V5 of macaque monkey visual cortex

V5 and V4 are areas of macaque monkey prestriate visual cortex that are specialized for involvement in different aspects of visual perception, namely motion for V5 (refs 1-4) and colour vision, with other possible functions, for V4 (refs 2, 5-9). Thus, it is unlikely that they should be fed the same information for further processing, yet both receive a strong input from patches of the upper layers of V2 (refs 10, 11), the area immediately adjoining the primary visual cortex, V1. V2, however, seems to comprise functionally distinct subregions, which can be revealed by staining the tissue for the mitochondrial enzyme cytochrome oxidase. Here we report that V4 and V5 are connected with separate cytochrome oxidase-defined subregions of V2, suggesting that cortical pathways dealing with motion and colour perception are segregated in their passage through V2, and reinforcing evidence for functional specialization in the visual cortex.     

Stereocilin-deficient mice reveal the origin of cochlear waveform distortions

Although the cochlea is an amplifier and a remarkably sensitive and finely tuned detector of sounds, it also produces conspicuous mechanical and electrical waveform distortions. These distortions reflect nonlinear mechanical interactions within the cochlea. By allowing one tone to suppress another (masking effect), they contribute to speech intelligibility. Tones can also combine to produce sounds with frequencies not present in the acoustic stimulus. These sounds compose the otoacoustic emissions that are extensively used to screen hearing in newborns. Because both cochlear amplification and distortion originate from the outer hair cells-one of the two types of sensory receptor cells-it has been speculated that they stem from a common mechanism. Here we show that the nonlinearity underlying cochlear waveform distortions relies on the presence of stereocilin, a protein defective in a recessive form of human deafness. Stereocilin was detected in association with horizontal top connectors, lateral links that join adjacent stereocilia within the outer hair cell's hair bundle. These links were absent in stereocilin-null mutant mice, which became progressively deaf. At the onset of hearing, however, their cochlear sensitivity and frequency tuning were almost normal, although masking was much reduced and both acoustic and electrical waveform distortions were completely lacking. From this unique functional situation, we conclude that the main source of cochlear waveform distortions is a deflection-dependent hair bundle stiffness resulting from constraints imposed by the horizontal top connectors, and not from the intrinsic nonlinear behaviour of the mechanoelectrical transducer channel.     

零汉语经验英语母语者汉语声调感知的判别分析研究

运用AX判别分析任务的方法,考察了零汉语学习经验的英语母语者在进行汉语声调辨别任务时的正确度和反应时间。结果表明：总体上被试汉语声调感知正确率较高,女性被试的感知正确率高于男性,男女被试均显现了阳平—上声、阴平—去声、阳平—去声最难区分,阴平—阴平、阴平—上声、上声—上声最易区分,其余声调对子的区分难度处于上述两类之间的感知难度等级。实验结果同时显示,反应时间与判断正确率基本成反比关系。实验结果还表明,其他因素例如声母、韵腹、韵尾等对于汉语声调的感知无明显影响。     

DSP应用--全数码助听器

研究DSP在可编程全数码助听器中的应用，主要包括方向性麦克风系统、双通道信号处理、消除声反馈、消除背景噪声、宽动态压缩、纯音发生器等部分的设计。     

云南文山话单字音声调的实验研究

相对于传统耳听手记的声调研究方法，实验语音学的方法可以使语音的研究结果更加客观化。该研究使用实验语音学方法考察了文山话单字音音高、调域、调长等，结合实际听感对实验值和传统值之间的区别做了探讨，得出文山话单字音的声调格局是：阴平为次高升调调型，调值为445；阳平为降调调型，且降幅较大，调值为532；上声为次高降平调调型，调值为433；去声为次低降平调调型，调值为211。     

债务加入的学理探究与实务辨析——以一则案例为视角

并存的债务承担与免责的债务承担是债务承担制度的两个组成部分。免责的债务承担存在的争议甚少，而并存的债务承担即债务加入的研究不足，实务中极易发生混淆。以并存的债务承担的定性分析为起点，对并存的债务承担的相关理论进行剖析，并对债务加入做出界定。     

脑干听觉诱发电位慢成分

以短声和短纯音刺激大鼠、分别观察刺激强度和刺激音持续时间对大鼠脑干听觉诱发电位慢成分的影响。经叠加后记录在ＢＡＥＰ慢成分，其时程约１－８ｍｓ；在刺激后５－６ｍｓ处可见一阳性波波峰，且波峰潜伏期与ＢＡＥＰ快成分的Ｖ波峰潜伏斯相近。     

Motion-induced spatial conflict

Borders defined by small changes in brightness (luminance contrast) or by differences in colour (chromatic contrast) appear to move more slowly than those defined by strong luminance contrast. As spatial coding is influenced by motion, if placed in close proximity, the different types of moving border might appear to drift apart. Using this configuration, we show here that observers instead report a clear illusory spatial jitter of the low-luminance-contrast boundary. This visible interaction between motion and spatial-position coding occurred at a characteristic rate (approximately 22.3 Hz), although the stimulus motion was continuous and invariant. The jitter rate did not vary with the speed of movement. The jitter was not due to small involuntary movements of the eyes, because it only occurred at a specific point within the stimulus, the low-luminance-contrast boundary. These findings show that the human visual system contains a neural mechanism that periodically resolves the spatial conflict created by adjacent moving borders that have the same physical but different perceptual speeds.