听力障碍与听力正常群体视觉注意发展及其机制的比较

One of the most important functions in the individual development is the interaction and integration of each sensory input. There exist two competing theories, i.e. the deficiency theory and the compensatory theory, regarding the origin and nature of changes in visual functions observed after auditory deprivation. The deficiency theory proposed that integrative processes are essential for normal development. In contrast, the compensatory theory stated that the loss of one sense may be met by a greater reliance upon, therefore an enhancement of the remaining senses. Given that hearing impaired children’s learning depends primarily on visual information, it is important to recognize the differences of visual attention between them and their hearing age-mates. Differences among age groups could exist in either selectivity or sustained attention. Study 1 and study 2 explored the selective and sustained attention development of hearing impaired and hearing students with average cognitive ability, aged from 7 years to college students. The analysis and discussion of the results are based on the visual attention development as well as deficiency theory and compensatory theory. According to the results of the study 1 and study 2, the spatial distribution and controlling of the visual attention between hearing impaired and hearing students were also investigated in the study 3 and study 4. The present work showed that: Firstly, both hearing impaired and hearing participants had the similar developmental trajectory of the sustained attention. The ability of children’s sustained attention appeared to improve with age, and in adolescence it reached the peak. The hearing impaired participants had the comparable sustained attention skills to the matched hearing ones. Besides, the results of the hearing impaired participants showed that they could maintain their attention and vigilance on the current task over the observation period. Secondly, group differences of visual attention development were found between hearing impaired and hearing participants. In the childhood, the visual attention developmental speed of the hearing impaired children was slower than that of the hearing ones. The selective attention skill of the hearing impaired were not comparable to the hearing ones, however, their selective skill improved with age, so in the adulthood, hearing impaired students showed the slight advantage in the selective attention skill over the hearing ones. Thirdly, hearing impaired and hearing participants showed the similar spatial distribution in the attention resources. In the low perceptual load condition, both participants were suffered great interference of the distrator at the fixation. In contrast, in the high perceptual load condition, hearing impaired adults were suffered more interference of the peripheral distractor, which suggested that they distributed more attention resources to the peripheral field when faced difficult tasks. Fourthly, both groups showed similar processing in the visual attention tasks. That is, they both searched the target with only the color feature in a parallel way, but in a serial way while processing orientation feature and the features with the combination of the color and orientation. Furthermore, the results indicated that two groups show similar ways in the attention controlling. In summary, the present study showed that visual attention development was dependent upon the integration of multimodal sensory information. Because of the interaction and integration of the input from various sensory, it has a negative impact on the intact sensory at the early stage of one sensory loss, however, it can better the functions of other intact sensory gradually with development and practice.

听觉想象的大脑表征

As a species of internal representation, how is mental imagery organized in the brain? There are two issues related to this question: the time course and the nature of mental imagery. On the nature of mental imagery, today's imagery debate is influenced by two opposing theories: (1) Pylyshyn’s propositional theory and (2) Kosslyn’s depictive representation theory. Behavioural studies indicated that imagery encodes properties of the physical world, such as the spacial and size information of the visual world. Neuroimaging and neuropsychological data indicated that sensory cortex; especially the primary sensory cortex, is involved in imagery. In visual modality, neuroimaging data further indicated that during visual imagery, spatial information is mapped in the primary visual, providing strong evidences for depictive theory. In the auditory modality, behavioural studies also indicated that auditory imagery represents loudness and pitch of sound; this kind of neuroimaging evidence, however, is absent. The aim of the present study was to investigate the time course of auditory imagery processing, and to provide the neuroimaging evidence that imaginal auditory representations encode loudness and pitch information, using the ERP method and a cue-imagery (S1)-S2 paradigm. The results revealed that imagery effects started with an enhancement of the P2, probably indexing the top-down allocation of attention to the imagery task; and continued into a more positive-going late positive potentials (LPC), probably reflecting the formation of auditory imagery. The amplitude of this LPC was inversely related to the pitch of the imagined sound, but directly related to the loudness of the imagined sound, which were consistent with auditory perception related N1 component, providing evidences that auditory imagery encodes pitch and loudness information. When the S2 showed difference in pitch of loudness from the previously imagined S1, the behavioral performance were significantly worse and accordingly a conflict related N2 was elicited; and the high conflict elicited greater N2 amplitude than low conflict condition, providing further evidences that imagery is analog of perception and can encode pitch and loudness information. The present study suggests that imagery starts with an mechanism of top-down allocation of attention to the imagery task; and continuing into the step of imagery formation during which the physical features of the imagined stimulus can be encoded, providing supports to Kosslyn’s depictive representation theory.

迁移性安慰剂效应的多模态机制 ：从痛觉到情绪的行为、ERP和fMRI研究

Although studies on placebo effect proved the placebo expectation established by pain-alleviating treatment could significantly alleviate later pain perception, or the placebo expectation established by anxiety-reducing treatment could significantly reduce the intensity of induced negative feelings, it is still unclear whether or not the placebo effect can occur in a transferable manner. That is, we still don’t know if the placebo expectation derived from pain-alleviating can significantly reduce later negative emotional arousal or not. Experiment 1: We compared the effect of the verbal expectation (purely verbal induction and without pain-alleviating reinforcement) with the reinforced expectation (building the belief in the placebo’s ataractic efficiency on unpleasant picture processing by secret reduction of the intensity of the pain-evoking stimulus) on the negative emotion. The results showed that the expectation, which was reinforced by actual analgesia, was transferable and could produce significant placebo effect on negative emotional arousal. However, the expectation that was merely induced by verbal instruction did not have such power. Experiment 2 both examined the direct analgesic effect of the placebo on the sensory pain (how strong is the pain stimulus) and emotional pain (how disturbing is the pain stimulus) and the transferable ataractic effect of the placebo on the negative emotion (how disturbing is the emotional picture stimulus), and further proved that the placebo expectation that was established from pain-reducing reinforcement not only induced significant placebo effect on pain, but also significant placebo effect on unpleasant feeling. These results support the viewpoint that the reduction of affective pain based on the conditioning mechanism plays an important role in the placebo analgesia, but can’t explain the transferred placebo effect on visual unpleasantness. Experiment 3 continued to use the paradigm of the reinforced expectation group and recorded the EEG activities, the data showed that the transferable placebo treatment was accompanied with decreased P2 amplitude and increased N2 distributed, and significant differences between the transferable placebo condition and the control condition (i.e., P2 and N2) were observed within the first 150-300 ms, a duration brief enough to rule out the possibility that differences between the two conditions merely reflect a bias “to try to please the investigator. In Experiment 4, we selected the placebo responders in the pre-experiment and let them to go through the formal fMRI scan. The results found that the transferable placebo treatment reduced the negative emotional response, emotion-responsive regions such as the amygdala, insula, anterior cingulate cortex and the thalamus showed an attenuated activation. And in the placebo condition, there was an enhanced activation in the subcollosal gyrus, which may be involved in emotional regulation. In conclusion, the transferable placebo treatment induced the reliable placebo effect on the behavior, EEG activity and bold signal, and we attempted to discuss the pychophysiological mechanism based on the positive expectancy.

心算年老化的认知心理机制及功能磁共振成像研究

Mechanisms underlying cognitive psychology and cerebral physiological of mental arithmetic with increasing are were studied by using behavioral methods and functional magnetic resonance imaging (fMRI). I. Studies on mechanism underlying cognitive psychology of mental arithmetic with increasing age These studies were accomplished in 172 normal subjects ranging from 20 to 79 years of age with above 12 years of education (Mean = 1.51, SD = 1.5). Five mental arithmetic tasks, "1000-1", "1000-3", "1000-7", "1000-13", "1000-17", were designed with a serial calculation in which subjects sequentially subtracted the same prime number (1, 3, 7, 13, 17) from another number 1000. The variables studied were mental arithmetic, age, working memory, and sensory-motor speed, and four studies were conducted: (1) Aging process of mental arithmetic with different difficulties, (2) mechanism of aging of mental arithmetic processing. (3) effects of working memory and sensory-motor speed on aging process of mental arithmetic, (4) model of cognitive aging of mental arithmetic, with statistical methods such as MANOVA, hierarchical multiple regression, stepwise regression analysis, structural equation modelling (SEM). The results were indicated as following: Study 1: There was an obvious interaction between age and mental arithmetic, in which reaction time (RT) increased with advancing age and more difficult mental arithmetic, and mental arithmetic efficiency (the ratio of accuracy to RT) deceased with advancing age and more difficult mental arithmetic; Mental arithmetic efficiency with different difficulties decreased in power function: Study 2: There were two mediators (latent variables) in aging process of mental arithmetic, and age had an effect on mental arithmetic with different difficulties through the two mediators; Study 3: There were obvious interactions between age and working memory, working memory and mental arithmetic; Working memory and sensory-motor speed had effects on aging process of mental arithmetic, in which the effect of working memory on aging process of mental arithmetic was about 30-50%, and the effect of sensory-motor speed on aging process of mental arithmetic was above 35%. Study 4: Age, working memory, and sensory-motor speed had effects on two latent variables (factor 1 and factor 2), then had effects on mental arithmetic with different difficulties through factor 1 which was relative to memory component, and factor 2 which relative to speed component and had an effect on factor 1 significantly. II. Functional magnetic resonance imaging study on metal arithmetic with increasing age This study was accomplished in 14 normal right-handed subjects ranging from 20 to 29 (7 subjects) and 60 to 69 (7 subjects) years of age by using functional magnetic resonance imaging apparatus, a superconductive Signa Horizon 1.5T MRI system. Two mental arithmetic tasks, "1000-3" and "1000-17", were designed with a serial calculation in which subjects sequentially subtracted the same prime number (3 or 17) from another number 1000 silently, and controlling task, "1000-0", in which subjects continually rehearsed number 1000 silently, was regarded as baseline, based on current "baseline-task" OFF-ON subtraction pattern. Original data collected by fMRI apparatus, were analyzed off-line in SUN SPARC working station by using current STIMULATE software. The analytical steps were composed of within-subject analysis, in which brain activated images about mental arithmetic with two difficulties were obtained by using t-test, and between-subject analysis, in which features of brain activation about mental arithmetic with two difficulties, the relationship between left and right hemisphere during mental arithmetic, and age differences of brain activation in young and elderly adults were examined by using non-parameter Wilcoxon test. The results were as following:

认知电位时空模式研究

This report mainly focused on methodology of spatiotemporal patterns (STP) of cognitive potentials or event-related potentials (ERP). The representation of STP of brain wave is an important issue in the research of neural assemblies. This paper described methods of parametric 3D head or brain modeling and its corresponding interpolation for functional imaging based on brain waves. The 3D interpolation method is an extension of cortical imaging technique. It can be used with transformed domain features of brain wave on realistic head or brain models. The simulating results suggests that it is a better method in comparison with the global nearest neighbor technique. A stable and definite STP of brainwave referred as microstate may become basic element for comprehending sophisticated cognitive processes. Fuzzy c-mean algorithm was applied to segmentation STPs of ERP into microstates and corresponding membership functions. The optimal microstate number was estimated with both the trends of objective function against increasing clustering number and the decorrelation technique base don microstate shape similarity. Comparable spatial patterns may occur at different moments in time with fuzzy indices and thus the serial processing limit generated from behavioral methods has been break through. High-resolution frequency domain analysis was carried out with multivariate autoregressive model. Bases on a 3D interpolation mentioned above, visualization of dynamical coordination of cerebral network was realized with magnitude-squared partial coherence. Those technique illustrated with multichannel ERP of 9 subjects when they undertook Strop task. Stroop effects involves several regions during post-perception stage with technique of statistical parameter mapping based F-test [SPM(F)]. As SPM(F) suggested task effects occurred within 100 ms after stimuli presentation involved several sensory regions, it may reflect the top-down processing effect.

樟柳碱和石杉碱甲对学习和记忆的影响及其有关机制的研究

Two experiments were designed to examine the role of the cholinergic agents, anisodine and huperzine A, and related mechanisms. In experiment 1, the effects of anisodine and huperzine A on rat performance in Morris water maze were observed. It was found that the drugs injected before daily training had significant effect on performance of place navigation task and transfer test, while the drugs injected after daily training, before retest and overtraining had no such effect. the results indicated that the drugs, which only have effects on reference memory related to cognitive mapping strategy, may mediate the acquisition process of memory. In experiment 2, the spontaneous hippocampol neuronal activities and the effects of the drugs on them in awake rabbits were observed. The results showed that anisodine had significant inhibitory effect on the activities, the opposite effect was found in huperzine A. Furthermore, sensory stimulation and administration of huperzine A have similar effects. It was sujested that hipppocampus be directly relavent to transmission of information to memory storage system, in which the role of central cholinergic system is critical.

A Robot that Walks: Emergent Behaviors from a Carefully Evolved Network

Most animals have significant behavioral expertise built in without having to explicitly learn it all from scratch. This expertise is a product of evolution of the organism; it can be viewed as a very long term form of learning which provides a structured system within which individuals might learn more specialized skills or abilities. This paper suggests one possible mechanism for analagous robot evolution by describing a carefully designed series of networks, each one being a strict augmentation of the previous one, which control a six legged walking machine capable of walking over rough terrain and following a person passively sensed in the infrared spectrum. As the completely decentralized networks are augmented, the robot's performance and behavior repertoire demonstrably improve. The rationale for such demonstrations is that they may provide a hint as to the requirements for automatically building massive networks to carry out complex sensory-motor tasks. The experiments with an actual robot ensure that an essence of reality is maintained and that no critical problems have been ignored.

Feature Matching for Object Localization in the Presence of Uncertainty

We consider the problem of matching model and sensory data features in the presence of geometric uncertainty, for the purpose of object localization and identification. The problem is to construct sets of model feature and sensory data feature pairs that are geometrically consistent given that there is uncertainty in the geometry of the sensory data features. If there is no geometric uncertainty, polynomial-time algorithms are possible for feature matching, yet these approaches can fail when there is uncertainty in the geometry of data features. Existing matching and recognition techniques which account for the geometric uncertainty in features either cannot guarantee finding a correct solution, or can construct geometrically consistent sets of feature pairs yet have worst case exponential complexity in terms of the number of features. The major new contribution of this work is to demonstrate a polynomial-time algorithm for constructing sets of geometrically consistent feature pairs given uncertainty in the geometry of the data features. We show that under a certain model of geometric uncertainty the feature matching problem in the presence of uncertainty is of polynomial complexity. This has important theoretical implications by demonstrating an upper bound on the complexity of the matching problem, an by offering insight into the nature of the matching problem itself. These insights prove useful in the solution to the matching problem in higher dimensional cases as well, such as matching three-dimensional models to either two or three-dimensional sensory data. The approach is based on an analysis of the space of feasible transformation parameters. This paper outlines the mathematical basis for the method, and describes the implementation of an algorithm for the procedure. Experiments demonstrating the method are reported.

Vision by Man and Machine

The development of increasingly sophisticated and powerful computers in the last few decades has frequently stimulated comparisons between them and the human brain. Such comparisons will become more earnest as computers are applied more and more to tasks formerly associated with essentially human activities and capabilities. The expectation of a coming generation of "intelligent" computers and robots with sensory, motor and even "intellectual" skills comparable in quality to (and quantitatively surpassing) our own is becoming more widespread and is, I believe, leading to a new and potentially productive analytical science of "information processing". In no field has this new approach been so precisely formulated and so thoroughly exemplified as in the field of vision. As the dominant sensory modality of man, vision is one of the major keys to our mastery of the environment, to our understanding and control of the objects which surround us. If we wish to created robots capable of performing complex manipulative tasks in a changing environment, we must surely endow them with (among other things) adequate visual powers. How can we set about designing such flexible and adaptive robots? In designing them, can we make use of our rapidly growing knowledge of the human brain, and if so, how at the same time, can our experiences in designing artificial vision systems help us to understand how the brain analyzes visual information?

Contact Sensors for Dexterous Robotic Hands

This thesis examines a tactile sensor and a thermal sensor for use with the Utah-MIT dexterous four fingered hand. Sensory feedback is critical or full utilization of its advanced manipulatory capabilities. The hand itself provides tendon tensions and joint angles information. However, planned control algorithms require more information than these sources can provide. The tactile sensor utilizes capacitive transduction with a novel design based entirely on silicone elastomers. It provides an 8 x 8 array of force cells with 1.9 mm center-to-center spacing. A pressure resolution of 8 significant bits is available over a 0 to 200 grams per square mm range. The thermal sensor measures a material's heat conductivity by radiating heat into an object and measuring the resulting temperature variations. This sensor has a 4 x 4 array of temperature cells with 3.5 mm center-to-center spacing. Experiments show that the thermal sensor can discriminate among material by detecting differences in their thermal conduction properties. Both sensors meet the stringent mounting requirements posed by the Utah-MIT hand. Combining them together to form a sensor with both tactile and thermal capabilities will ultimately be possible. The computational requirements for controlling a sensor equipped dexterous hand are severe. Conventional single processor computers do not provide adequate performance. To overcome these difficulties, a computational architecture based on interconnecting high performance microcomputers and a set of software primitives tailored for sensor driven control has been proposed. The system has been implemented and tested on the Utah-MIT hand. The hand, equipped with tactile and thermal sensors and controlled by its computational architecture, is one of the most advanced robotic manipulatory devices available worldwide. Other ongoing projects will exploit these tools and allow the hand to perform tasks that exceed the capabilities of current generation robots.

The Coupled Depth/Slope Approach to Surface Reconstruction

Reconstructing a surface from sparse sensory data is a well known problem in computer vision. Early vision modules typically supply sparse depth, orientation and discontinuity information. The surface reconstruction module incorporates these sparse and possibly conflicting measurements of a surface into a consistent, dense depth map. The coupled depth/slope model developed here provides a novel computational solution to the surface reconstruction problem. This method explicitly computes dense slope representation as well as dense depth representations. This marked change from previous surface reconstruction algorithms allows a natural integration of orientation constraints into the surface description, a feature not easily incorporated into earlier algorithms. In addition, the coupled depth/ slope model generalizes to allow for varying amounts of smoothness at different locations on the surface. This computational model helps conceptualize the problem and leads to two possible implementations- analog and digital. The model can be implemented as an electrical or biological analog network since the only computations required at each locally connected node are averages, additions and subtractions. A parallel digital algorithm can be derived by using finite difference approximations. The resulting system of coupled equations can be solved iteratively on a mesh-pf-processors computer, such as the Connection Machine. Furthermore, concurrent multi-grid methods are designed to speed the convergence of this digital algorithm.

Computer System for Visual Recognition Using Active Knowledge

A system for visual recognition is described, with implications for the general problem of representation of knowledge to assist control. The immediate objective is a computer system that will recognize objects in a visual scene, specifically hammers. The computer receives an array of light intensities from a device like a television camera. It is to locate and identify the hammer if one is present. The computer must produce from the numerical "sensory data" a symbolic description that constitutes its perception of the scene. Of primary concern is the control of the recognition process. Control decisions should be guided by the partial results obtained on the scene. If a hammer handle is observed this should suggest that the handle is part of a hammer and advise where to look for the hammer head. The particular knowledge that a handle has been found combines with general knowledge about hammers to influence the recognition process. This use of knowledge to direct control is denoted here by the term "active knowledge". A descriptive formalism is presented for visual knowledge which identifies the relationships relevant to the active use of the knowledge. A control structure is provided which can apply knowledge organized in this fashion actively to the processing of a given scene.

Research into automatic error recovery

Lee, M., Hardy, N., & Barnes, D. P. (1984). Research into automatic error recovery. 65-69. Paper presented at 4th International Conference on Robot Vision and Sensory Controls, London, London, United Kingdom.

Knowledge based error recovery in industrial robots

M. H. Lee, D. P. Barnes, and N. W. Hardy. Knowledge based error recovery in industrial robots. In Proc. 8th. Int. Joint Conf. Artificial Intelligence, pages 824-826, Karlsruhe, FDR., 1983.

A control and monitoring system for multiple-sensor industrial robots

Barnes, D. P., Lee, M. H., Hardy, N. W. (1983). A control and monitoring system for multiple-sensor industrial robots. In Proc. 3rd. Int. Conf. Robot Vision and Sensory Controls, Cambridge, MA. USA., 471-479.