High-level Aspects Research Articles

Breaking Continuous Flash Suppression: A New Measure of Unconscious Processing during Interocular Suppression?

Until recently, it has been thought that under interocular suppression high-level visual processing is strongly inhibited if not abolished. With the development of continuous flash suppression (CFS), a variant of binocular rivalry, this notion has now been challenged by a number of reports showing that even high-level aspects of visual stimuli, such as familiarity, affect the time stimuli need to overcome CFS and emerge into awareness. In this “breaking continuous flash suppression” (b-CFS) paradigm, differential unconscious processing during suppression is inferred when (a) speeded detection responses to initially invisible stimuli differ, and (b) no comparable differences are found in non-rivalrous control conditions supposed to measure non-specific threshold differences between stimuli. The aim of the present study was to critically evaluate these assumptions. In six experiments we compared the detection of upright and inverted faces. We found that not only under CFS, but also in control conditions upright faces were detected faster and more accurately than inverted faces, although the effect was larger during CFS. However, reaction time (RT) distributions indicated critical differences between the CFS and the control condition. When RT distributions were matched, similar effect sizes were obtained in both conditions. Moreover, subjective ratings revealed that CFS and control conditions are not perceptually comparable. These findings cast doubt on the usefulness of non-rivalrous control conditions to rule out non-specific threshold differences as a cause of shorter detection latencies during CFS. Thus, at least in its present form, the b-CFS paradigm cannot provide unequivocal evidence for unconscious processing under interocular suppression. Nevertheless, our findings also demonstrate that the b-CFS paradigm can be fruitfully applied as a highly sensitive device to probe differences between stimuli in their potency to gain access to awareness.

Empowered by wireless communication

In recent years, tremendous progress has been made in understanding the dynamics of vehicle traffic flow and traffic congestion by interpreting traffic as a multiparticle system. This helps to explain the onset and persistence of many undesired phenomena, for example, traffic jams. It also reflects the apparent helplessness of drivers in traffic, who feel like passive particles that are pushed around by exterior forces; one of the crucial aspects is the inability to communicate and coordinate with other traffic participants. We present distributed methods for solving these fundamental problems, employing modern wireless, ad-hoc, multi-hop networks. The underlying idea is to use these capabilities as the basis for self-organizing methods for coordinating data collection and processing, recognizing traffic phenomena, and changing their structure by coordinated behavior. The overall objective is a multi-level approach that reaches from protocols for local wireless communication, data dissemination, pattern recognition, over hierarchical structuring and coordinated behavior, all the way to large-scale traffic regulation. In this article, we describe three types of results: (i) self-organizing and distributed methods for maintaining and collecting data (using our concept of Hovering Data Clouds ); (ii) adaptive data dissemination for traffic information systems; (iii) methods for self-recognition of traffic jams. We conclude by describing higher-level aspects of our work.

ENHANCING KNOWLEDGE MANAGEMENT IN ONLINE COLLABORATIVE LEARNING

This paper aims to explore two crucial aspects of collaborative work and learning: on the one hand, the importance of enabling collaborative learning applications to capture and structure the information generated by group activity and, on the other hand, to extract the relevant knowledge in order to provide learners and tutors with efficient awareness, feedback and support with regards to group performance and collaboration. To this end, in this paper we first propose a conceptual model for data analysis and management that identifies and classifies the many kinds of indicators that describe collaboration and learning into high-level aspects of collaboration. Then, we provide a computational platform that, at a first step, collects and classifies both the event information generated asynchronously from the users' actions and the labeled dialogues from the synchronous collaboration according to these indicators. This information is then analyzed in next steps to eventually extract and present to participants the relevant knowledge about the collaboration. The ultimate aim of this platform is to efficiently embed information and knowledge into collaborative learning applications. We eventually suggest a generalization of our approach to be used in diverse collaborative learning situations and domains.

Mathematical thinking and task design

Mathematical thinking is difficult to define precisely but most authors agree that the following are important aspects of it: conjecturing, reasoning and proving, abstraction, generalization and specialization. However, recent studies have shown that many sets of mathematical tasks produced emphasize lower level skills, such as memorization and the routine application of algorithms or procedures. In this paper we survey the literature on the design and use of tasks that aim to encourage higher level aspects of mathematical thinking in learners of mathematics at all levels. The frameworks presented here aim to guide task designers when writing a set of exercises.

Disentangling syntax and intelligibility in auditory language comprehension

Studies of the neural basis of spoken language comprehension typically focus on aspects of auditory processing by varying signal intelligibility, or on higher-level aspects of language processing such as syntax. Most studies in either of these threads of language research report brain activation including peaks in the superior temporal gyrus (STG) and/or the superior temporal sulcus (STS), but it is not clear why these areas are recruited in functionally different studies. The current fMRI study aims to disentangle the functional neuroanatomy of intelligibility and syntax in an orthogonal design. The data substantiate functional dissociations between STS and STG in the left and right hemispheres: first, manipulations of speech intelligibility yield bilateral mid-anterior STS peak activation, whereas syntactic phrase structure violations elicit strongly left-lateralized mid STG and posterior STS activation. Second, ROI analyses indicate all interactions of speech intelligibility and syntactic correctness to be located in the left frontal and temporal cortex, while the observed right-hemispheric activations reflect less specific responses to intelligibility and syntax. Our data demonstrate that the mid-to-anterior STS activation is associated with increasing speech intelligibility, while the mid-to-posterior STG/STS is more sensitive to syntactic information within the speech.

Effects of Early Pattern Deprivation on Visual Development

Studies of children treated for dense cataract shed light on the extent to which pattern stimulation drives normal visual development and whether there are sensitive periods during which an abnormal visual environment is especially detrimental. Here, we summarize the findings to date into five general principles: (1) At least for low-level vision, aspects of vision that develop the earliest are the least likely to be adversely affected by abnormal visual input whereas those that develop later are affected more severely. (2) Early visual input is necessary to preserve the neural infrastructure for later visual learning, even for visual capabilities that will not appear until later in development. (3) The development of both the dorsal and ventral streams depends on normal visual input. (4) After monocular deprivation has been treated by surgical removal of the cataractous lens, the interactions between the aphakic and phakic eyes are competitive for low-level vision but are complementary for high-level vision. (5) There are multiple sensitive periods during which experience can influence visual development.The studies described here have important implications for understanding normal development. They indicate that patterned visual input immediately after birth plays a vital role in the construction and preservation of the neural architecture that will later mediate sensitivity to both basic and higher level aspects of vision. The period during which patterned visual input is necessary for normal visual development varies widely across different aspects of vision and can range from only a few months after birth to more than the first 10 years of life. The results point to new research questions on why early visual deprivation can cause later deficits, what limits adult plasticity, and whether effective rehabilitation in other areas can provide new clues for the treatment of amblyopia.

Supporting agile supply chains using a service-oriented shop floor

The globalized nature of current business environments led to the emergence of new networked enterprise organizational paradigms (supply chains, extended enterprises, virtual enterprises, collaborative networks, etc.) to meet changing requirements and tackle profitable but volatile opportunities overall agility is required. Eventually the shop floor will have to react and accommodate (re)adjustments in the supply chain making it an important piece in the competitiveness puzzle. So far, the research focus has been in high level aspects of supply chain management and the integration of shop floor activities in the process has been left relatively unattended. However, shop floor data is increasingly required in business tools that support decision making. In this context, failing to support agility at shop floor level can compromise the agility of the supply chain. Recent developments in networked information technologies and embedded devices allow enabling intelligence in shop floor rendering it an active and live entity that further enhances the dynamics of the supply chain. The goal of the present work, supported by an implemented test case in the assembly domain, is to demonstrate how one is able to seamless integrate the shop floor with external tools and achieve a highly reconfigurable environment that adapts to changing production requirements and disturbances using service-oriented technology.

Using GenERTiCA to Generation Code from RT-UML: A Case Study

Tool support is essential to allow the use of Model-Driven Engineering (MDE) in the design of distributed embedded real-time systems. GenERTiCA is a flexible tool that supports a MDE approach, which uses concepts of Aspect-Oriented Development (AOD) to handle non-functional requirements from real-time and embedded systems domain. This paper presents a comprehensive case study that illustrates GenERTiCA usage to generate source code from UML models. GenERTiCA also performs aspects weaving using aspect's information specified in UML models. Results regarding source code generation for a Java platform based on the Real-Time Specification for Java (RTSJ) are presented. Additionally, this paper discusses the implementation of some aspects of a high-level aspects framework, named DERAF, using the mentioned platform.

A METHODOLOGY FOR SUPPORTING SYSTEM-LEVEL DESIGN SPACE EXPLORATION AT HIGHER LEVELS OF ABSTRACTION

The complexity of modern embedded systems requires a revised and systematic approach to efficient and concurrent management of hardware (HW) and software (SW) parts in a codesign process. In order to optimally meet the ever-increasing design requirements and at the same time leverage design productivity, higher level aspects need to be addressed before worrying about the HW/SW boundary. This paper deals with high-level aspects of system-level modeling and provides modeling extension, from which contemporary related methodologies can greatly benefit. High-level aspects, their influence on the entire design flow, and systematic integration into the codesign environment are presented. An approach is proposed with a higher level of abstraction that helps bridge the gap between informal and formal system specifications. Higher level design decisions are enabled, avoiding premature ad hoc design decisions. Applicability of the proposed high-level codesign concepts is illustrated with a case study.

The 33rd Sir Frederick Bartlett Lecture Cognitive neuropsychiatry and delusional belief

Cognitive neuropsychiatry is a new field of cognitive psychology which seeks to learn more about the normal operation of high-level aspects of cognition such as belief formation, reasoning, decision making, theory of mind, and pragmatics by studying people in whom such processes are abnormal. So far, the high-level cognitive process most widely studied in cognitive neuropsychiatry has been belief formation, investigated by examining people with delusional beliefs. This paper describes some of the forms of delusional belief that have been examined from this perspective and offers a general two-deficit cognitive-neuropsychiatric account of delusional belief.

Motor planning in congenital hemiplegia

Purpose. Cerebral Palsy (CP) is a broad definition of a neurological condition in which disorders in movement execution and postural control limit the performance of activities of daily living. In this paper, we first review studies on motor planning in hemiplegic CP. Second, preliminary data of a recent study on eye-hand coordination in participants with hemiplegic CP are presented. Here, the potential role of vision for online and prospective control of action was examined.Method. Review and presentation of preliminary data of an eye- and hand movement registration experiment in hemiplegic CP.Results. Deficits in motor planning in hemiplegic CP contribute to limitations of activities of daily living. In the second part, exemplary plots of eye-hand coordination are presented for the affected and unaffected hand in one participant with hemiplegic CP, and for the preferred hand in controls, both as an illustration of the research methodology and to give an impression of the observed gaze patterns.Conclusion. Research on CP should not solely focus on low-level aspects of action execution, but also take into account the more high-level aspects of motor control, such as planning. Possible deviations therein may be sought in altered gaze patterns as illustrated in the paper.

Biologically Based Computational Models of High-Level Cognition

Computer models based on the detailed biology of the brain can help us understand the myriad complexities of human cognition and intelligence. Here, we review models of the higher level aspects of human intelligence, which depend critically on the prefrontal cortex and associated subcortical areas. The picture emerging from a convergence of detailed mechanistic models and more abstract functional models represents a synthesis between analog and digital forms of computation. Specifically, the need for robust active maintenance and rapid updating of information in the prefrontal cortex appears to be satisfied by bistable activation states and dynamic gating mechanisms. These mechanisms are fundamental to digital computers and may be critical for the distinctive aspects of human intelligence.

Native Speakers of Arabic and ESL Texts: Evidence for the Transfer of Written Word Identification Processes

English as a second language (ESL) teachers have long noted that native speakers of Arabic exhibit exceptional difficulty with English reading comprehension (e.g., Thompson-Panos & Thomas-Ruzic, 1983). Most existing work in this area has looked to higher level aspects of reading such as familiarity with discourse structure and cultural knowledge to explain native Arabic speakers' ESL reading difficulties (Abu Rabia, 1996). However, higher level processes often depend on lower level processes, such as letter and word identification, and deficient lower level processing can inhibit reading comprehension (Koda, 1990). Given important differences in the written representation of vowel information in English and Arabic writing, it was hypothesized that the English reading comprehension difficulties experienced by Arabic speakers might also reflect nontarget-like lower level processing of letters and words. Two experiments compare the reading processes of native Arabic speakers to the reading processes of native English speakers and non-Arabic ESL learners and provide some evidence that native Arabic speakers are less aware of vowel letters in English texts than either control group. This differential awareness of vowel letters may contribute to native Arabic speakers' ESL reading comprehension difficulties. The implications of this research for ESL pedagogy are discussed.

Health Literacy, Morbidity, and Quality of Life Among Individuals With Spinal Cord Injury

Objectives: Health literacy has been related to indicators of health outcomes in a number of populations,but not in spinal cord injury (SCI). The current study aimed to describe levels of health literacy in SCI and to investigate its possible associations with morbidity, health-related quality of life, functional independence,community participation, and life satisfaction.Design: Cross-sectional survey of 107 community-living people with SCI recruited in a New jersey outpatient SCI center. Primary measures were the Test of Functional Health Literacy in Adults (TOFHLA), standard questions about morbidity from the Behavioral Risk FactorsSurveillance Study, the Craig Handicap Assessment and Reporting Technique (CHART), Short Form-12 (SF-12), and Diener's Satisfaction with Life Scale.Results: Health literacy was marginal or inadequate (TOFHLA = 0–74) in only 14% of the sample. TOFHLA scores correlated significantly with physical health morbidity, even after control for severity of motor paralysis and education. American Spinal Injury Association (ASIA) Motor Scores were correlated with physical morbidityand CHART Physical Independence scores; and education was related to community Mobility, Occupation, and Economic Independence, and Satisfaction with Life scores, independent of other factors. Rasch analysis identified ceiling measurement limitations in the TOFHLA.Conclusions: Health literacy levels in this sample were higher than those found in other groups. Health literacy was independently related to physical health morbidity, but its associations with other outcomes were limited, entwined with education, and affected by severity of injury. Future research might examine higher level aspects of health literacy to overcome ceiling measurement problems. Mediators of the association between health literacy and morbidity, such as health self-care behaviors, should also be examined.

Linguistic processing in visual and modality-nonspecific brain areas: PET recordings during selective attention

Positron emission tomography (PET) was used to investigate the neural basis of selective processing of linguistic material during concurrent presentation of multiple stimulus streams (“cocktail-party effect”). Fifteen healthy right-handed adult males were to attend to one of three simultaneously presented messages: one presented visually, one to the left ear, and one to the right ear. During the control condition, subjects attended to visually presented consonant letter strings and ignored auditory messages. This paper reports the modality-nonspecific language processing and visual word-form processing, whereas the auditory attention effects have been reported elsewhere [Cogn. Brain Res. 17 (2003) 201]. The left-hemisphere areas activated by both the selective processing of text and speech were as follows: the inferior prefrontal (Brodmann's area, BA 45, 47), anterior temporal (BA 38), posterior insular (BA 13), inferior (BA 20) and middle temporal (BA 21), occipital (BA 18/30) cortices, the caudate nucleus, and the amygdala. In addition, bilateral activations were observed in the medial occipito-temporal cortex and the cerebellum. Decreases of activation during both text and speech processing were found in the parietal (BA 7, 40), frontal (BA 6, 8, 44) and occipito-temporal (BA 37) regions of the right hemisphere. Furthermore, the present data suggest that the left occipito-temporal cortex (BA 18, 20, 37, 21) can be subdivided into three functionally distinct regions in the posterior–anterior direction on the basis of their activation during attentive processing of sublexical orthography, visual word form, and supramodal higher-level aspects of language.

Analysis of neural mechanisms underlying verbal fluency in cytoarchitectonically defined stereotaxic space—The roles of Brodmann areas 44 and 45

We investigated neural activations underlying a verbal fluency task and cytoarchitectonic probabilistic maps of Broca's speech region (Brodmann's areas 44 and 45). To do so, we reanalyzed data from a previous functional magnetic resonance imaging (fMRI) [Brain 125 (2002) 1024] and from a cytoarchitectonic study [J. Comp. Neurol. 412 (1999) 319] and developed a method to combine both data sets. In the fMRI experiment, verbal fluency was investigated in 11 healthy volunteers, who covertly produced words from predefined categories. A factorial design was used with factors verbal class (semantic vs. overlearned fluency) and switching between categories (no vs. yes). fMRI data analysis employed SPM99 (Statistical Parametric Mapping). Cytoarchitectonic maps of areas 44 and 45 were derived from histologic sections of 10 postmortem brains. Both the in vivo fMRI and postmortem MR data were warped to a common reference brain using a new elastic warping tool. Cytoarchitectonic probability maps with stereotaxic information about intersubject variability were calculated for both areas and superimposed on the functional data, which showed the involvement of left hemisphere areas with verbal fluency relative to the baseline. Semantic relative to overlearned fluency showed greater involvement of left area 45 than of 44. Thus, although both areas participate in verbal fluency, they do so differentially. Left area 45 is more involved in semantic aspects of language processing, while area 44 is probably involved in high-level aspects of programming speech production per se. The combination of functional data analysis with a new elastic warping tool and cytoarchitectonic maps opens new perspectives for analyzing the cortical networks involved in language.

Understanding the neurobiological consequences of early exposure to psychotropic drugs: linking behavior with molecules

Children receive significant exposure to psychotropic drugs. Some psychiatric disorders are diagnosed and treated in children as young as 2 years old, resulting in exposure to prescription stimulants, antidepressants, and mood stabilizers during brain development. Difficulties in diagnoses at such young ages increase the likelihood that children who are not affected by these disorders receive drug exposure inadvertently. Additionally, the increased availability of caffeine-containing beverages in schools has facilitated exposure to this stimulant in children. However, the consequences of exposure to psychotropic drugs during brain development are not understood. When we exposed rats to the prescription stimulant methylphenidate during early adolescence, we discovered long-lasting behavioral and molecular alterations that were consistent with dramatic changes in the function of brain reward systems. In future work, it will be important to determine if other classes of psychotropic drugs cause these same effects, and whether these effects will also occur if drug exposure begins during other periods of development. Moreover, it will be critical to use more powerful behavioral methods that are sensitive to high-level aspects of motivation and cognitive function, and to establish causal links between developmental exposure-related alterations in these complex behaviors and specific alterations in the molecular biology of key brain regions. This approach may identify classes of psychotropic drugs that have high or low propensities to cause behavioral and molecular adaptations that endure into adulthood. It may also identify periods of development during which administration of these agents is particularly safe or risky.

Performance of reconfigurable architectures for image-processing applications

Reconfigurable architectures combine a programmable-visible interface and the high-level aspects of a computer's design. The goal of this work is to explore the architectural behaviour of remote reconfigurable systems that are part of general-purpose computers. Our approach analyses various issues arising from the connection of processors with FPGA-based microarchitecture to an existing commodity microprocessor via a standard bus. The quantitative evaluation considers image-processing applications and shows that the maximum performance depends on the amount of data processed by the reconfigurable hardware. Taking images with 256 × 256 pixels, a moderate FPGA capacity of 1E+5 logic blocks provides two orders of magnitude of performance improvement over a Pentium III processor for most of our benchmarks. However, the performance benefits exhibited by reconfigurable architectures may be deeply influenced by some design parameters. This paper studies the impact of hardware capacity, reconfiguration time, memory organisation, and bus bandwidth on the performance achieved by FPGA-based systems. Those image-processing benchmarks that can exhibit high-performance improvement would require about 150 memory banks of 256 bytes each and a bus bandwidth as high as 30 GB/s. This quantitative approach can be applied to the design of high-performance reconfigurable coprocessors for multimedia applications.

Electrical stimulation of the supplementary eye fields in the head-free macaque evokes kinematically normal gaze shifts.

The supplementary eye fields (SEFs), located on the dorsomedial surface of the frontal cortex, are involved in high-level aspects of saccade generation. Some reports suggest that the same area could also be involved in the generation of motor commands for the head. If so, it is important to establish whether this structure encodes eye and head commands separately or gaze commands that give rise to coordinated eye-head movements. Here we systematically stimulated (50 microA, 300 Hz, 200 ms) the SEF of two head-free (head unrestrained) macaques while recording three-dimensional eye and head rotations. A total of 55 sites were found to consistently elicit saccade-like gaze movements, always in the contralateral direction with variable vertical components, and ranging in average amplitude from 5 to 60 degrees. These movements were always a combination of eye-in-head saccades and head-in-space movements. We then performed a comparison between these movements and natural gaze shifts. The kinematics of the elicited movements (i.e., their temporal structure, their velocity-amplitude relationships, and the relative contributions of the eye and the head as a function of movement amplitude) were indistinguishable from those of natural gaze shifts. Additionally, they obeyed the same three-dimensional constraints as natural gaze shifts (i.e., eye-in-head movements obeyed Listing's law, whereas head- and eye-in-space movements obeyed Donders' law). In summary, gaze movements evoked by stimulating the SEF were indistinguishable from natural coordinated eye-head gaze shifts. Based on this we conclude that the SEF explicitly encodes gaze and that the kinematics aspects of eye-head coordination are implicitly specified by mechanisms downstream from the SEF.

The significance of sensory-motor functions as indicators of brain dysfunction in children

Sensory-perceptual and motor functions are closely dependent on the integrity of the brain and nervous system. Standardized tests have been developed to assess these functions, but such tests are not routinely used to evaluate children who are suspected of having a neuropsychological basis for their difficulties. Higher-level functions (such as verbal and academic abilities, executive functioning, etc.) are obviously important in producing successful performances, but the brain and nervous system correlates of these abilities are less well defined than the correlates for sensory-motor abilities. Our contention is that tests from these two general areas (higher-level and lower-level aspects of brain functioning) can be used effectively in a complementary manner to evaluate individual children. The first step in this process is to evaluate formal sensory-motor tests and to assess their validity as a brief preliminary examination used to differentiate between brain-damaged and control children. The results of this study demonstrated striking differences between the groups and indicated that sensory-motor testing might serve very effectively, when used in conjunction with higher-level tests, to identify those children whose higher-level impairment is due to brain impairment rather than a lack of environmental opportunities or advantages.