Neural signatures of economic parameters during decision-making: a functional MRI (FMRI), electroencephalography (EEG) and autonomic monitoring study.

PubMed

Minati, Ludovico; Grisoli, Marina; Franceschetti, Silvana; Epifani, Francesca; Granvillano, Alice; Medford, Nick; Harrison, Neil A; Piacentini, Sylvie; Critchley, Hugo D

2012-01-01

Adaptive behaviour requires an ability to obtain rewards by choosing between different risky options. Financial gambles can be used to study effective decision-making experimentally, and to distinguish processes involved in choice option evaluation from outcome feedback and other contextual factors. Here, we used a paradigm where participants evaluated 'mixed' gambles, each presenting a potential gain and a potential loss and an associated variable outcome probability. We recorded neural responses using autonomic monitoring, electroencephalography (EEG) and functional neuroimaging (fMRI), and used a univariate, parametric design to test for correlations with the eleven economic parameters that varied across gambles, including expected value (EV) and amount magnitude. Consistent with behavioural economic theory, participants were risk-averse. Gamble evaluation generated detectable autonomic responses, but only weak correlations with outcome uncertainty were found, suggesting that peripheral autonomic feedback does not play a major role in this task. Long-latency stimulus-evoked EEG potentials were sensitive to expected gain and expected value, while alpha-band power reflected expected loss and amount magnitude, suggesting parallel representations of distinct economic qualities in cortical activation and central arousal. Neural correlates of expected value representation were localized using fMRI to ventromedial prefrontal cortex, while the processing of other economic parameters was associated with distinct patterns across lateral prefrontal, cingulate, insula and occipital cortices including default-mode network and early visual areas. These multimodal data provide complementary evidence for distributed substrates of choice evaluation across multiple, predominantly cortical, brain systems wherein distinct regions are preferentially attuned to specific economic features. Our findings extend biologically-plausible models of risky decision-making while providing potential biomarkers of economic representations that can be applied to the study of deficits in motivational behaviour in neurological and psychiatric patients.

An extended retinotopic map of mouse cortex

PubMed Central

Zhuang, Jun; Ng, Lydia; Williams, Derric; Valley, Matthew; Li, Yang; Garrett, Marina; Waters, Jack

2017-01-01

Visual perception and behavior are mediated by cortical areas that have been distinguished using architectonic and retinotopic criteria. We employed fluorescence imaging and GCaMP6 reporter mice to generate retinotopic maps, revealing additional regions of retinotopic organization that extend into barrel and retrosplenial cortices. Aligning retinotopic maps to architectonic borders, we found a mismatch in border location, indicating that architectonic borders are not aligned with the retinotopic transition at the vertical meridian. We also assessed the representation of visual space within each region, finding that four visual areas bordering V1 (LM, P, PM and RL) display complementary representations, with overlap primarily at the central hemifield. Our results extend our understanding of the organization of mouse cortex to include up to 16 distinct retinotopically organized regions. DOI: http://dx.doi.org/10.7554/eLife.18372.001 PMID:28059700

Tactile Toe Agnosia and Percept of a "Missing Toe" in Healthy Humans.

PubMed

Cicmil, Nela; Meyer, Achim P; Stein, John F

2016-03-01

A disturbance of body representation is central to many neurological and psychiatric conditions, but the mechanisms by which body representations are constructed by the brain are not fully understood. We demonstrate a directional disturbance in tactile identification of the toes in healthy humans. Nineteen young adult participants underwent tactile stimulation of the digits with the eyes closed and verbally reported the identity of the stimulated digit. In the majority of individuals, responses to the second and third toes were significantly biased toward the laterally neighboring digit. The directional bias was greater for the nondominant foot and was affected by the identity of the immediately preceding stimulated toe. Unexpectedly, 9/19 participants reported the subjective experience of a "missing toe" or "missing space" during the protocol. These findings challenge current models of somatosensory localization, as they cannot be explained simply by a lack of distinct representations for toes compared with fingers, or by overt toe-finger correspondences. We present a novel theory of equal spatial representations of digit width combined with a "preceding neighbor" effect to explain the observed phenomena. The diagnostic implications for neurological disorders that involve "digit agnosia" are discussed. © The Author(s) 2015.

Geometry segmentation of voxelized representations of heterogeneous microstructures using betweenness centrality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Rui; Singh, Sudhanshu S.; Chawla, Nikhilesh

2016-08-15

We present a robust method for automating removal of “segregation artifacts” in segmented tomographic images of three-dimensional heterogeneous microstructures. The objective of this method is to accurately identify and separate discrete features in composite materials where limitations in imaging resolution lead to spurious connections near close contacts. The method utilizes betweenness centrality, a measure of the importance of a node in the connectivity of a graph network, to identify voxels that create artificial bridges between otherwise distinct geometric features. To facilitate automation of the algorithm, we develop a relative centrality metric to allow for the selection of a threshold criterionmore » that is not sensitive to inclusion size or shape. As a demonstration of the effectiveness of the algorithm, we report on the segmentation of a 3D reconstruction of a SiC particle reinforced aluminum alloy, imaged by X-ray synchrotron tomography.« less

Evidence for multiple, distinct representations of the human body.

PubMed

Schwoebel, John; Coslett, H Branch

2005-04-01

Previous data from single-case and small group studies have suggested distinctions among structural, conceptual, and online sensorimotor representations of the human body. We developed a battery of tasks to further examine the prevalence and anatomic substrates of these body representations. The battery was administered to 70 stroke patients. Fifty-one percent of the patients were impaired relative to controls on at least one body representation measure. Further, principal components analysis of the patient data as well as direct comparisons of patient and control performance suggested a triple dissociation between measures of the 3 putative body representations. Consistent with previous distinctions between the "what" and "how" pathways, lesions of the left temporal lobe were most consistently associated with impaired performance on tasks assessing knowledge of the shape or lexical-semantic information about the body, whereas lesions of the dorsolateral frontal and parietal regions resulted in impaired performance on tasks requiring on-line coding of body posture.

Impacts of distinct observations during the 2009 Prince William Sound field experiment: A data assimilation study

NASA Astrophysics Data System (ADS)

Li, Zhijin; Chao, Yi; Farrara, John D.; McWilliams, James C.

2013-07-01

A set of data assimilation experiments, known as Observing System Experiments (OSEs) are performed to assess the relative impacts of different types of observations acquired during the 2009 Prince William Sound Field Experiment. The observations assimilated consist primarily of two types: High Frequency (HF) radar surface velocities and vertical profiles of temperature/salinity (T/S) measured by ships, moorings, an Autonomous Underwater Vehicle and a glider. The impact of all the observations, HF radar surface velocities, and T/S profiles is assessed. Without data assimilation, a frequently occurring cyclonic eddy in the central Sound is overly persistent and intense. The assimilation of the HF radar velocities effectively reduces these biases and improves the representation of the velocities as well as the T/S fields in the Sound. The assimilation of the T/S profiles improves the large scale representation of the temperature/salinity and also the velocity field in the central Sound. The combination of the HF radar surface velocities and sparse T/S profiles results in an observing system capable of representing the circulation in the Sound reliably and thus producing analyses and forecasts with useful skill.

Zif268 mRNA Expression Patterns Reveal a Distinct Impact of Early Pattern Vision Deprivation on the Development of Primary Visual Cortical Areas in the Cat.

PubMed

Laskowska-Macios, Karolina; Zapasnik, Monika; Hu, Tjing-Tjing; Kossut, Malgorzata; Arckens, Lutgarde; Burnat, Kalina

2015-10-01

Pattern vision deprivation (BD) can induce permanent deficits in global motion perception. The impact of timing and duration of BD on the maturation of the central and peripheral visual field representations in cat primary visual areas 17 and 18 remains unknown. We compared early BD, from eye opening for 2, 4, or 6 months, with late onset BD, after 2 months of normal vision, using the expression pattern of the visually driven activity reporter gene zif268 as readout. Decreasing zif268 mRNA levels between months 2 and 4 characterized the normal maturation of the (supra)granular layers of the central and peripheral visual field representations in areas 17 and 18. In general, all BD conditions had higher than normal zif268 levels. In area 17, early BD induced a delayed decrease, beginning later in peripheral than in central area 17. In contrast, the decrease occurred between months 2 and 4 throughout area 18. Lack of pattern vision stimulation during the first 4 months of life therefore has a different impact on the development of areas 17 and 18. A high zif268 expression level at a time when normal vision is restored seems to predict the capacity of a visual area to compensate for BD. © The Author 2014. Published by Oxford University Press.

Representation in Memory.

ERIC Educational Resources Information Center

Rumelhart, David E.; Norman, Donald A.

This paper reviews work on the representation of knowledge from within psychology and artificial intelligence. The work covers the nature of representation, the distinction between the represented world and the representing world, and significant issues concerned with propositional, analogical, and superpositional representations. Specific topics…

Color pattern analysis of nymphalid butterfly wings: revision of the nymphalid groundplan.

PubMed

Otaki, Joji M

2012-09-01

To better understand the developmental mechanisms of color pattern variation in butterfly wings, it is important to construct an accurate representation of pattern elements, known as the "nymphalid groundplan". However, some aspects of the current groundplan remain elusive. Here, I examined wing-wide elemental patterns of various nymphalid butterflies and confirmed that wing-wide color patterns are composed of the border, central, and basal symmetry systems. The central and basal symmetry systems can express circular patterns resembling eyespots, indicating that these systems have developmental mechanisms similar to those of the border symmetry system. The wing root band commonly occurs as a distinct symmetry system independent from the basal symmetry system. In addition, the marginal and submarginal bands are likely generated as a single system, referred to as the "marginal band system". Background spaces between two symmetry systems are sometimes light in coloration and can produce white bands, contributing significantly to color pattern diversity. When an element is enlarged with a pale central area, a visually similar (yet developmentally distinct) white band is produced. Based on the symmetric relationships of elements, I propose that both the central and border symmetry systems are comprised of "core elements" (the discal spot and the border ocelli, respectively) and a pair of "paracore elements" (the distal and proximal bands and the parafocal elements, respectively). Both core and paracore elements can be doubled, or outlined. Developmentally, this system configuration is consistent with the induction model, but not with the concentration gradient model for positional information.

Does the Grammatical Count/Mass Distinction Affect Semantic Representations? Evidence from Experiments in English and Japanese

ERIC Educational Resources Information Center

Iwasaki, Noriko; Vinson, David P.; Vigliocco, Gabriella

2010-01-01

We investigate linguistic relativity effects by examining whether the grammatical count/mass distinction in English affects English speakers' semantic representations of noun referents, as compared with those of Japanese speakers, whose language does not grammatically distinguish nouns for countability. We used two tasks which are sensitive to…

Positivity of the English Language

PubMed Central

Kloumann, Isabel M.; Danforth, Christopher M.; Harris, Kameron Decker; Bliss, Catherine A.; Dodds, Peter Sheridan

2012-01-01

Over the last million years, human language has emerged and evolved as a fundamental instrument of social communication and semiotic representation. People use language in part to convey emotional information, leading to the central and contingent questions: (1) What is the emotional spectrum of natural language? and (2) Are natural languages neutrally, positively, or negatively biased? Here, we report that the human-perceived positivity of over 10,000 of the most frequently used English words exhibits a clear positive bias. More deeply, we characterize and quantify distributions of word positivity for four large and distinct corpora, demonstrating that their form is broadly invariant with respect to frequency of word use. PMID:22247779

Developmental Changes in Information Central to Artifact Representation: Evidence from "Functional Fluency" Tasks

ERIC Educational Resources Information Center

Defeyter, Margaret Anne; Avons, S. E.; German, Tamsin C.

2007-01-01

Research suggests that while information about design is a central feature of older children's artifact representations it may be less important in the artifact representations of younger children. Three experiments explore the pattern of responses that 5- and 7-year-old children generate when asked to produce multiple uses for familiar…

Choosing the Rules: Distinct and Overlapping Frontoparietal Representations of Task Rules for Perceptual Decisions

PubMed Central

Kriegeskorte, Nikolaus; Carlin, Johan D.; Rowe, James B.

2013-01-01

Behavior is governed by rules that associate stimuli with responses and outcomes. Human and monkey studies have shown that rule-specific information is widely represented in the frontoparietal cortex. However, it is not known how establishing a rule under different contexts affects its neural representation. Here, we use event-related functional MRI (fMRI) and multivoxel pattern classification methods to investigate the human brain's mechanisms of establishing and maintaining rules for multiple perceptual decision tasks. Rules were either chosen by participants or specifically instructed to them, and the fMRI activation patterns representing rule-specific information were compared between these contexts. We show that frontoparietal regions differ in the properties of their rule representations during active maintenance before execution. First, rule-specific information maintained in the dorsolateral and medial frontal cortex depends on the context in which it was established (chosen vs specified). Second, rule representations maintained in the ventrolateral frontal and parietal cortex are independent of the context in which they were established. Furthermore, we found that the rule-specific coding maintained in anticipation of stimuli may change with execution of the rule: representations in context-independent regions remain invariant from maintenance to execution stages, whereas rule representations in context-dependent regions do not generalize to execution stage. The identification of distinct frontoparietal systems with context-independent and context-dependent task rule representations, and the distinction between anticipatory and executive rule representations, provide new insights into the functional architecture of goal-directed behavior. PMID:23864675

Triple representation of language, working memory, social and emotion processing in the cerebellum: convergent evidence from task and seed-based resting-state fMRI analyses in a single large cohort.

PubMed

Guell, Xavier; Gabrieli, John D E; Schmahmann, Jeremy D

2018-05-15

Delineation of functional topography is critical to the evolving understanding of the cerebellum's role in a wide range of nervous system functions. We used data from the Human Connectome Project (n = 787) to analyze cerebellar fMRI task activation (motor, working memory, language, social and emotion processing) and resting-state functional connectivity calculated from cerebral cortical seeds corresponding to the peak Cohen's d of each task contrast. The combination of exceptional statistical power, activation from both motor and multiple non-motor tasks in the same participants, and convergent resting-state networks in the same participants revealed novel aspects of the functional topography of the human cerebellum. Consistent with prior studies there were two distinct representations of motor activation. Newly revealed were three distinct representations each for working memory, language, social, and emotional task processing that were largely separate for these four cognitive and affective domains. In most cases, the task-based activations and the corresponding resting-network correlations were congruent in identifying the two motor representations and the three non-motor representations that were unique to working memory, language, social cognition, and emotion. The definitive localization and characterization of distinct triple representations for cognition and emotion task processing in the cerebellum opens up new basic science questions as to why there are triple representations (what different functions are enabled by the different representations?) and new clinical questions (what are the differing consequences of lesions to the different representations?). Copyright © 2018 Elsevier Inc. All rights reserved.

The media of sociology: tight or loose translations?

PubMed

Guggenheim, Michael

2015-06-01

Sociologists have increasingly come to recognize that the discipline has unduly privileged textual representations, but efforts to incorporate visual and other media are still only in their beginning. This paper develops an analysis of the ways objects of knowledge are translated into other media, in order to understand the visual practices of sociology and to point out unused possibilities. I argue that the discourse on visual sociology, by assuming that photographs are less objective than text, is based on an asymmetric media-determinism and on a misleading notion of objectivity. Instead, I suggest to analyse media with the concept of translations. I introduce several kinds of translations, most centrally the distinction between tight and loose ones. I show that many sciences, such as biology, focus on tight translations, using a variety of media and manipulating both research objects and representations. Sociology, in contrast, uses both tight and loose translations, but uses the latter only for texts. For visuals, sociology restricts itself to what I call 'the documentary': focusing on mechanical recording technologies without manipulating either the object of research or the representation. I conclude by discussing three rare examples of what is largely excluded in sociology: visual loose translations, visual tight translations based on non-mechanical recording technologies, and visual tight translations based on mechanical recording technologies that include the manipulation of both object and representation. © London School of Economics and Political Science 2015.

Characterizing psychopathy using DSM-5 personality traits.

PubMed

Strickland, Casey M; Drislane, Laura E; Lucy, Megan; Krueger, Robert F; Patrick, Christopher J

2013-06-01

Despite its importance historically and contemporarily, psychopathy is not recognized in the current Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revised (DSM-IV-TR). Its closest counterpart, antisocial personality disorder, includes strong representation of behavioral deviance symptoms but weak representation of affective-interpersonal features considered central to psychopathy. The current study evaluated the extent to which psychopathy and its distinctive facets, indexed by the Triarchic Psychopathy Measure, can be assessed effectively using traits from the dimensional model of personality pathology developed for DSM-5, operationalized by the Personality Inventory for DSM-5 (PID-5). Results indicate that (a) facets of psychopathy entailing impulsive externalization and callous aggression are well-represented by traits from the PID-5 considered relevant to antisocial personality disorder, and (b) the boldness facet of psychopathy can be effectively captured using additional PID-5 traits. These findings provide evidence that the dimensional model of personality pathology embodied in the PID-5 provides effective trait-based coverage of psychopathy and its facets.

Toward a visuospatial developmental account of sequence-space synesthesia

PubMed Central

Price, Mark C.; Pearson, David G.

2013-01-01

Sequence-space synesthetes experience some sequences (e.g., numbers, calendar units) as arranged in spatial forms, i.e., spatial patterns in their mind's eye or even outside their body. Various explanations have been offered for this phenomenon. Here we argue that these spatial forms are continuous with varieties of non-synesthetic visuospatial imagery and share their central characteristics. This includes their dynamic and elaborative nature, their involuntary feel, and consistency over time. Drawing from literatures on mental imagery and working memory, we suggest how the initial acquisition and subsequent elaboration of spatial forms could be accounted for in terms of the known developmental trajectory of visuospatial representations. This extends from the formation of image-based representations of verbal material in childhood to the later maturation of dynamic control of imagery. Individual differences in the development of visuospatial style also account for variation in the character of spatial forms, e.g., in terms of distinctions such as visual versus spatial imagery, or ego-centric versus object-based transformations. PMID:24187538

Wrongdoing and Retribution: Children's Conceptions of Illness Causality in a Central Indian Village.

PubMed

Froerer, Peggy

2007-12-01

This paper is a study of children's conceptions of illness causality. Based on ethnographic research in a central Indian tribal community, it is a response to the lack of systematic attention within mainstream anthropology on children, and within medical anthropology on children's understanding of illness causation. A combination of participant observation and structured interviews was used to examine local distinctions between 'natural' and 'supernatural' illness, which are underpinned by ideas about supernatural retribution. The focus in this paper is on how children learn and reason about such ideas, and on the processes by which they assume culpability for 'supernatural' illnesses. By arguing that children do not simply replicate adult conceptions about illness causality but instead apply their own experience to their understanding and representation of such ideas, this paper challenges taken-for-granted assumptions about the acquisition and reproduction of cultural knowledge.

Sparse genetic tracing reveals regionally specific functional organization of mammalian nociceptors.

PubMed

Olson, William; Abdus-Saboor, Ishmail; Cui, Lian; Burdge, Justin; Raabe, Tobias; Ma, Minghong; Luo, Wenqin

2017-10-12

The human distal limbs have a high spatial acuity for noxious stimuli but a low density of pain-sensing neurites. To elucidate mechanisms underlying regional differences in processing nociception, we sparsely traced non-peptidergic nociceptors across the body using a newly generated Mrgprd CreERT2 mouse line. We found that mouse plantar paw skin is also innervated by a low density of Mrgprd + nociceptors, while individual arbors in different locations are comparable in size. Surprisingly, the central arbors of plantar paw and trunk innervating nociceptors have distinct morphologies in the spinal cord. This regional difference is well correlated with a heightened signal transmission for plantar paw circuits, as revealed by both spinal cord slice recordings and behavior assays. Taken together, our results elucidate a novel somatotopic functional organization of the mammalian pain system and suggest that regional central arbor structure could facilitate the "enlarged representation" of plantar paw regions in the CNS.

The loss of short-term visual representations over time: decay or temporal distinctiveness?

PubMed

Mercer, Tom

2014-12-01

There has been much recent interest in the loss of visual short-term memories over the passage of time. According to decay theory, visual representations are gradually forgotten as time passes, reflecting a slow and steady distortion of the memory trace. However, this is controversial and decay effects can be explained in other ways. The present experiment aimed to reexamine the maintenance and loss of visual information over the short term. Decay and temporal distinctiveness models were tested using a delayed discrimination task, in which participants compared complex and novel objects over unfilled retention intervals of variable length. Experiment 1 found no significant change in the accuracy of visual memory from 2 to 6 s, but the gap separating trials reliably influenced task performance. Experiment 2 found evidence for information loss at a 10-s retention interval, but temporally separating trials restored the fidelity of visual memory, possibly because temporally isolated representations are distinct from older memory traces. In conclusion, visual representations lose accuracy at some point after 6 s, but only within temporally crowded contexts. These findings highlight the importance of temporal distinctiveness within visual short-term memory. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Sinkhole-like structures as bioproductivity hotspots in the Abrolhos Bank

NASA Astrophysics Data System (ADS)

Cavalcanti, Giselle S.; Gregoracci, Gustavo B.; Longo, Leila de L.; Bastos, Alex C.; Ferreira, Camilo M.; Francini-Filho, Ronaldo B.; Paranhos, Rodolfo; Ghisolfi, Renato D.; Krüger, Ricardo; Güth, Arthur Z.; Sumida, Paulo Y. G.; Bruce, Thiago; Maia-Neto, Oswaldo; de O. Santos, Eidy; Iida, Tetsuya; Moura, Rodrigo L.; Amado-Filho, Gilberto M.; Thompson, Fabiano L.

2013-11-01

We performed a biological survey in the novel system of sinkhole-like structures ("buracas") of the Abrolhos Bank, Brazil. We found dissimilar benthic assemblages and higher nutrient concentration, microbial abundance (and activity) and fish abundance inside the buracas than in the surrounding rhodolith beds. Our results support the view that these cup-shaped structures trap and accumulate organic matter, functioning as productivity hotspots in the mid and outer shelf of the central portion of the Abrolhos Bank shelf, where they aggregate biomass of commercially important fishes. This distinctive system is being increasingly pressured by commercial fisheries and needs urgent management measures such as fishing effort control and representation in the network of Marine Protected Areas (MPAS).

Contrasting effects of feature-based statistics on the categorisation and identification of visual objects

PubMed Central

Taylor, Kirsten I.; Devereux, Barry J.; Acres, Kadia; Randall, Billi; Tyler, Lorraine K.

2013-01-01

Conceptual representations are at the heart of our mental lives, involved in every aspect of cognitive functioning. Despite their centrality, a long-standing debate persists as to how the meanings of concepts are represented and processed. Many accounts agree that the meanings of concrete concepts are represented by their individual features, but disagree about the importance of different feature-based variables: some views stress the importance of the information carried by distinctive features in conceptual processing, others the features which are shared over many concepts, and still others the extent to which features co-occur. We suggest that previously disparate theoretical positions and experimental findings can be unified by an account which claims that task demands determine how concepts are processed in addition to the effects of feature distinctiveness and co-occurrence. We tested these predictions in a basic-level naming task which relies on distinctive feature information (Experiment 1) and a domain decision task which relies on shared feature information (Experiment 2). Both used large-scale regression designs with the same visual objects, and mixed-effects models incorporating participant, session, stimulus-related and feature statistic variables to model the performance. We found that concepts with relatively more distinctive and more highly correlated distinctive relative to shared features facilitated basic-level naming latencies, while concepts with relatively more shared and more highly correlated shared relative to distinctive features speeded domain decisions. These findings demonstrate that the feature statistics of distinctiveness (shared vs. distinctive) and correlational strength, as well as the task demands, determine how concept meaning is processed in the conceptual system. PMID:22137770

Informatic parcellation of the network involved in the computation of subjective value

PubMed Central

Rangel, Antonio

2014-01-01

Understanding how the brain computes value is a basic question in neuroscience. Although individual studies have driven this progress, meta-analyses provide an opportunity to test hypotheses that require large collections of data. We carry out a meta-analysis of a large set of functional magnetic resonance imaging studies of value computation to address several key questions. First, what is the full set of brain areas that reliably correlate with stimulus values when they need to be computed? Second, is this set of areas organized into dissociable functional networks? Third, is a distinct network of regions involved in the computation of stimulus values at decision and outcome? Finally, are different brain areas involved in the computation of stimulus values for different reward modalities? Our results demonstrate the centrality of ventromedial prefrontal cortex (VMPFC), ventral striatum and posterior cingulate cortex (PCC) in the computation of value across tasks, reward modalities and stages of the decision-making process. We also find evidence of distinct subnetworks of co-activation within VMPFC, one involving central VMPFC and dorsal PCC and another involving more anterior VMPFC, left angular gyrus and ventral PCC. Finally, we identify a posterior-to-anterior gradient of value representations corresponding to concrete-to-abstract rewards. PMID:23887811

Knowledge Construction and Knowledge Representation in High School Students' Design of Hypermedia Documents

ERIC Educational Resources Information Center

Chen, Pearl; McGrath, Diane

2003-01-01

This study documented the processes of knowledge construction and knowledge representation in high school students' hypermedia design projects. Analysis of knowledge construction in linking and structural building yielded distinct types and subtypes of hypermedia documents, which were characterized by four features of knowledge representation: (a)…

Comprehending expository texts: the dynamic neurobiological correlates of building a coherent text representation

PubMed Central

Swett, Katherine; Miller, Amanda C.; Burns, Scott; Hoeft, Fumiko; Davis, Nicole; Petrill, Stephen A.; Cutting, Laurie E.

2013-01-01

Little is known about the neural correlates of expository text comprehension. In this study, we sought to identify neural networks underlying expository text comprehension, how those networks change over the course of comprehension, and whether information central to the overall meaning of the text is functionally distinct from peripheral information. Seventeen adult subjects read expository passages while being scanned using functional magnetic resonance imaging (fMRI). By convolving phrase onsets with the hemodynamic response function (HRF), we were able to identify regions that increase and decrease in activation over the course of passage comprehension. We found that expository text comprehension relies on the co-activation of the semantic control network and regions in the posterior midline previously associated with mental model updating and integration [posterior cingulate cortex (PCC) and precuneus (PCU)]. When compared to single word comprehension, left PCC and left Angular Gyrus (AG) were activated only for discourse-level comprehension. Over the course of comprehension, reliance on the same regions in the semantic control network increased, while a parietal region associated with attention [intraparietal sulcus (IPS)] decreased. These results parallel previous findings in narrative comprehension that the initial stages of mental model building require greater visuospatial attention processes, while maintenance of the model increasingly relies on semantic integration regions. Additionally, we used an event-related analysis to examine phrases central to the text's overall meaning vs. peripheral phrases. It was found that central ideas are functionally distinct from peripheral ideas, showing greater activation in the PCC and PCU, while over the course of passage comprehension, central and peripheral ideas increasingly recruit different parts of the semantic control network. The finding that central information elicits greater response in mental model updating regions than peripheral ideas supports previous behavioral models on the cognitive importance of distinguishing textual centrality. PMID:24376411

The representation of semantic knowledge in a child with Williams syndrome.

PubMed

Robinson, Sally J; Temple, Christine M

2009-05-01

This study investigated whether there are distinct types of semantic knowledge with distinct representational bases during development. The representation of semantic knowledge in a teenage child (S.T.) with Williams syndrome was explored for the categories of animals, fruit, and vegetables, manipulable objects, and nonmanipulable objects. S.T.'s lexical stores were of a normal size but the volume of "sensory feature" semantic knowledge she generated in oral descriptions was reduced. In visual recognition decisions, S.T. made more false positives to nonitems than did controls. Although overall naming of pictures was unimpaired, S.T. exhibited a category-specific anomia for nonmanipulable objects and impaired naming of visual-feature descriptions of animals. S.T.'s performance was interpreted as reflecting the impaired integration of distinctive features from perceptual input, which may impact upon nonmanipulable objects to a greater extent than the other knowledge categories. Performance was used to inform adult-based models of semantic representation, with category structure proposed to emerge due to differing degrees of dependency upon underlying knowledge types, feature correlations, and the acquisition of information from modality-specific processing modules.

Representation and the Removal of State Capitals, 1776-1812.

ERIC Educational Resources Information Center

Zagarri, Rosemarie

1988-01-01

Discusses the process of moving state capitals (between 1776 and 1812) to achieve equal representation through geographic centrality. Presents contemporary arguments for the process including the belief that central location of the capital promoted better attendance by all state representatives. Describes how the system was replaced by numerical…

Images as Representations: Visual Sources on Education and Childhood in the Past

ERIC Educational Resources Information Center

Dekker, Jeroen J.H.

2015-01-01

The challenge of using images for the history of education and childhood will be addressed in this article by looking at them as representations. Central is the relationship between representations and reality. The focus is on the power of paintings as representations of aspects of realities. First the meaning of representation for images as…

Changing Internal Representations of Self and Other: Philosophical Tools for the Attachment-Informed Psychotherapy with Perpetrators and Victims of Violence1

PubMed Central

Pârvan, Alexandra

2016-01-01

Attachment research shows that the formation of unconscious, insecure representations of the self, the other, and the self-other relations is linked to perpetration and receipt of violence. Attachment-focused therapy aims to change these internal schemata to more secure, adaptive representations by therapeutic work addressed to senses, emotions, and behavior. The paper proposes a new approach to altering the self and other representations in offenders and victims: it involves intellectual reflection on self, will, action and responsibility informed by Augustine’s views, facilitated by actual relational experience, and translated into a distinct self-soothing strategy. The reflective-experiential approach can complement existing methods of working with violent or traumatized individuals both within and outside an attachment theory framework. It consists in: identifying that a non-reflective nondistinction between self and behavior supports damaging self- and other- representations and interactions; proposing ways for clients to comprehend and consciously operate with the distinction between self and action. PMID:28936108

Contrasting effects of feature-based statistics on the categorisation and basic-level identification of visual objects.

PubMed

Taylor, Kirsten I; Devereux, Barry J; Acres, Kadia; Randall, Billi; Tyler, Lorraine K

2012-03-01

Conceptual representations are at the heart of our mental lives, involved in every aspect of cognitive functioning. Despite their centrality, a long-standing debate persists as to how the meanings of concepts are represented and processed. Many accounts agree that the meanings of concrete concepts are represented by their individual features, but disagree about the importance of different feature-based variables: some views stress the importance of the information carried by distinctive features in conceptual processing, others the features which are shared over many concepts, and still others the extent to which features co-occur. We suggest that previously disparate theoretical positions and experimental findings can be unified by an account which claims that task demands determine how concepts are processed in addition to the effects of feature distinctiveness and co-occurrence. We tested these predictions in a basic-level naming task which relies on distinctive feature information (Experiment 1) and a domain decision task which relies on shared feature information (Experiment 2). Both used large-scale regression designs with the same visual objects, and mixed-effects models incorporating participant, session, stimulus-related and feature statistic variables to model the performance. We found that concepts with relatively more distinctive and more highly correlated distinctive relative to shared features facilitated basic-level naming latencies, while concepts with relatively more shared and more highly correlated shared relative to distinctive features speeded domain decisions. These findings demonstrate that the feature statistics of distinctiveness (shared vs. distinctive) and correlational strength, as well as the task demands, determine how concept meaning is processed in the conceptual system. Copyright © 2011 Elsevier B.V. All rights reserved.

Calculus Students' Representation Use in Group-Work and Individual Settings

ERIC Educational Resources Information Center

Zazkis, Dov

2013-01-01

The study of student representation use and specifically the distinction between analytic and visual representations has fueled a long line of mathematics education literature that began more than 35 years ago. This literature can be partitioned into two bodies of work, one that is primarily cognitive and one that is primarily social. In spite of…

On the Roles of External Knowledge Representations in Assessment Design

ERIC Educational Resources Information Center

Mislevy, Robert J.; Behrens, John T.; Bennett, Randy E.; Demark, Sarah F.; Frezzo, Dennis C.; Levy, Roy; Robinson, Daniel H.; Rutstein, Daisy Wise; Shute, Valerie J.; Stanley, Ken; Winters, Fielding I.

2010-01-01

People use external knowledge representations (KRs) to identify, depict, transform, store, share, and archive information. Learning how to work with KRs is central to be-coming proficient in virtually every discipline. As such, KRs play central roles in curriculum, instruction, and assessment. We describe five key roles of KRs in assessment: (1)…

On the Roles of External Knowledge Representations in Assessment Design. CSE Report 722

ERIC Educational Resources Information Center

Mislevy, Robert J.; Behrens, John T.; Bennett, Randy E.; Demark, Sarah F.; Frezzo, Dennis C.; Levy, Roy; Robinson, Daniel H.; Rutstein, Daisy Wise; Shute, Valerie J.; Stanley, Ken; Winters, Fielding I.

2007-01-01

People use external knowledge representations (EKRs) to identify, depict, transform, store, share, and archive information. Learning how to work with EKRs is central to becoming proficient in virtually every discipline. As such, EKRs play central roles in curriculum, instruction, and assessment. Five key roles of EKRs in educational assessment are…

Wanting, liking, and preference construction.

PubMed

Dai, Xianchi; Brendl, C Miguel; Ariely, Dan

2010-06-01

According to theories on preference construction, multiple preferences result from multiple contexts (e.g., loss vs. gain frames). This implies that people can have different representations of a preference in different contexts. Drawing on Berridge's (1999) distinction between unconscious liking and wanting, we hypothesize that people may have multiple representations of a preference toward an object even within a single context. Specifically, we propose that people can have different representations of an object's motivational value, or incentive value, versus its emotional value, or likability, even when the object is placed in the same context. Study 1 establishes a divergence between incentive value and likability of faces using behavioral measures. Studies 2A and 2B, using self-report measures, provide support for our main hypothesis that people are perfectly aware of these distinct representations and are able to access them concurrently at will. We also discuss implications of our findings for the truism that people seek pleasure and for expectancy-value theories.

Sensitivity to musical structure in the human brain

PubMed Central

McDermott, Josh H.; Norman-Haignere, Sam; Kanwisher, Nancy

2012-01-01

Evidence from brain-damaged patients suggests that regions in the temporal lobes, distinct from those engaged in lower-level auditory analysis, process the pitch and rhythmic structure in music. In contrast, neuroimaging studies targeting the representation of music structure have primarily implicated regions in the inferior frontal cortices. Combining individual-subject fMRI analyses with a scrambling method that manipulated musical structure, we provide evidence of brain regions sensitive to musical structure bilaterally in the temporal lobes, thus reconciling the neuroimaging and patient findings. We further show that these regions are sensitive to the scrambling of both pitch and rhythmic structure but are insensitive to high-level linguistic structure. Our results suggest the existence of brain regions with representations of musical structure that are distinct from high-level linguistic representations and lower-level acoustic representations. These regions provide targets for future research investigating possible neural specialization for music or its associated mental processes. PMID:23019005

DNA → RNA: What Do Students Think the Arrow Means?

PubMed Central

Fisk, J. Nick; Newman, Dina L.

2014-01-01

The central dogma of molecular biology, a model that has remained intact for decades, describes the transfer of genetic information from DNA to protein though an RNA intermediate. While recent work has illustrated many exceptions to the central dogma, it is still a common model used to describe and study the relationship between genes and protein products. We investigated understanding of central dogma concepts and found that students are not primed to think about information when presented with the canonical figure of the central dogma. We also uncovered conceptual errors in student interpretation of the meaning of the transcription arrow in the central dogma representation; 36% of students (n = 128; all undergraduate levels) described transcription as a chemical conversion of DNA into RNA or suggested that RNA existed before the process of transcription began. Interviews confirm that students with weak conceptual understanding of information flow find inappropriate meaning in the canonical representation of central dogma. Therefore, we suggest that use of this representation during instruction can be counterproductive unless educators are explicit about the underlying meaning. PMID:26086664

Multivariate Pattern Analysis Reveals Category-Related Organization of Semantic Representations in Anterior Temporal Cortex.

PubMed

Malone, Patrick S; Glezer, Laurie S; Kim, Judy; Jiang, Xiong; Riesenhuber, Maximilian

2016-09-28

The neural substrates of semantic representation have been the subject of much controversy. The study of semantic representations is complicated by difficulty in disentangling perceptual and semantic influences on neural activity, as well as in identifying stimulus-driven, "bottom-up" semantic selectivity unconfounded by top-down task-related modulations. To address these challenges, we trained human subjects to associate pseudowords (TPWs) with various animal and tool categories. To decode semantic representations of these TPWs, we used multivariate pattern classification of fMRI data acquired while subjects performed a semantic oddball detection task. Crucially, the classifier was trained and tested on disjoint sets of TPWs, so that the classifier had to use the semantic information from the training set to correctly classify the test set. Animal and tool TPWs were successfully decoded based on fMRI activity in spatially distinct subregions of the left medial anterior temporal lobe (LATL). In addition, tools (but not animals) were successfully decoded from activity in the left inferior parietal lobule. The tool-selective LATL subregion showed greater functional connectivity with left inferior parietal lobule and ventral premotor cortex, indicating that each LATL subregion exhibits distinct patterns of connectivity. Our findings demonstrate category-selective organization of semantic representations in LATL into spatially distinct subregions, continuing the lateral-medial segregation of activation in posterior temporal cortex previously observed in response to images of animals and tools, respectively. Together, our results provide evidence for segregation of processing hierarchies for different classes of objects and the existence of multiple, category-specific semantic networks in the brain. The location and specificity of semantic representations in the brain are still widely debated. We trained human participants to associate specific pseudowords with various animal and tool categories, and used multivariate pattern classification of fMRI data to decode the semantic representations of the trained pseudowords. We found that: (1) animal and tool information was organized in category-selective subregions of medial left anterior temporal lobe (LATL); (2) tools, but not animals, were encoded in left inferior parietal lobe; and (3) LATL subregions exhibited distinct patterns of functional connectivity with category-related regions across cortex. Our findings suggest that semantic knowledge in LATL is organized in category-related subregions, providing evidence for the existence of multiple, category-specific semantic representations in the brain. Copyright © 2016 the authors 0270-6474/16/3610089-08$15.00/0.

Impacts of distinct observations during the 2009 Prince William Sound field experiment: A data assimilation study

NASA Astrophysics Data System (ADS)

Li, Z.; Chao, Y.; Farrara, J.; McWilliams, J. C.

2012-12-01

A set of data assimilation experiments, known as Observing System Experiments (OSEs), are performed to assess the relative impacts of different types of observations acquired during the 2009 Prince William Sound Field Experiment. The observations assimilated consist primarily of three types: High Frequency (HF) radar surface velocities, vertical profiles of temperature/salinity (T/S) measured by ships, moorings, Autonomous Underwater Vehicles and gliders, and satellite sea surface temperatures (SSTs). The impact of all the observations, HF radar surface velocities, and T/S profiles is assessed. Without data assimilation, a frequently occurring cyclonic eddy in the central Sound is overly persistent and intense. The assimilation of the HF radar velocities effectively reduces these biases and improves the representation of the velocities as well as the T/S fields in the Sound. The assimilation of the T/S profiles improves the large scale representation of the temperature/salinity and also the velocity field in the central Sound. The combination of the HF radar surface velocities and sparse T/S profiles results in an observing system capable of representing the circulation in the Sound reliably and thus producing analyses and forecasts with useful skill. It is suggested that a potentially promising observing network could be based on satellite SSHs and SSTs along with sparse T/S profiles, and future satellite SSHs with wide swath coverage and higher resolution may offer excellent data that will be of great use for predicting the circulation in the Sound.

The felt presence of other minds: Predictive processing, counterfactual predictions, and mentalising in autism.

PubMed

Palmer, Colin J; Seth, Anil K; Hohwy, Jakob

2015-11-01

The mental states of other people are components of the external world that modulate the activity of our sensory epithelia. Recent probabilistic frameworks that cast perception as unconscious inference on the external causes of sensory input can thus be expanded to enfold the brain's representation of others' mental states. This paper examines this subject in the context of the debate concerning the extent to which we have perceptual awareness of other minds. In particular, we suggest that the notion of perceptual presence helps to refine this debate: are others' mental states experienced as veridical qualities of the perceptual world around us? This experiential aspect of social cognition may be central to conditions such as autism spectrum disorder, where representations of others' mental states seem to be selectively compromised. Importantly, recent work ties perceptual presence to the counterfactual predictions of hierarchical generative models that are suggested to perform unconscious inference in the brain. This enables a characterisation of mental state representations in terms of their associated counterfactual predictions, allowing a distinction between spontaneous and explicit forms of mentalising within the framework of predictive processing. This leads to a hypothesis that social cognition in autism spectrum disorder is characterised by a diminished set of counterfactual predictions and the reduced perceptual presence of others' mental states. Copyright © 2015 Elsevier Inc. All rights reserved.

'What' Is Happening in the Dorsal Visual Pathway.

PubMed

Freud, Erez; Plaut, David C; Behrmann, Marlene

2016-10-01

The cortical visual system is almost universally thought to be segregated into two anatomically and functionally distinct pathways: a ventral occipitotemporal pathway that subserves object perception, and a dorsal occipitoparietal pathway that subserves object localization and visually guided action. Accumulating evidence from both human and non-human primate studies, however, challenges this binary distinction and suggests that regions in the dorsal pathway contain object representations that are independent of those in ventral cortex and that play a functional role in object perception. We review here the evidence implicating dorsal object representations, and we propose an account of the anatomical organization, functional contributions, and origins of these representations in the service of perception. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identifying elemental genomic track types and representing them uniformly

PubMed Central

2011-01-01

Background With the recent advances and availability of various high-throughput sequencing technologies, data on many molecular aspects, such as gene regulation, chromatin dynamics, and the three-dimensional organization of DNA, are rapidly being generated in an increasing number of laboratories. The variation in biological context, and the increasingly dispersed mode of data generation, imply a need for precise, interoperable and flexible representations of genomic features through formats that are easy to parse. A host of alternative formats are currently available and in use, complicating analysis and tool development. The issue of whether and how the multitude of formats reflects varying underlying characteristics of data has to our knowledge not previously been systematically treated. Results We here identify intrinsic distinctions between genomic features, and argue that the distinctions imply that a certain variation in the representation of features as genomic tracks is warranted. Four core informational properties of tracks are discussed: gaps, lengths, values and interconnections. From this we delineate fifteen generic track types. Based on the track type distinctions, we characterize major existing representational formats and find that the track types are not adequately supported by any single format. We also find, in contrast to the XML formats, that none of the existing tabular formats are conveniently extendable to support all track types. We thus propose two unified formats for track data, an improved XML format, BioXSD 1.1, and a new tabular format, GTrack 1.0. Conclusions The defined track types are shown to capture relevant distinctions between genomic annotation tracks, resulting in varying representational needs and analysis possibilities. The proposed formats, GTrack 1.0 and BioXSD 1.1, cater to the identified track distinctions and emphasize preciseness, flexibility and parsing convenience. PMID:22208806

Color-motion feature-binding errors are mediated by a higher-order chromatic representation

PubMed Central

Shevell, Steven K.; Wang, Wei

2017-01-01

Peripheral and central moving objects of the same color may be perceived to move in the same direction even though peripheral objects have a different true direction of motion [Nature 429, 262 (2004)]. The perceived, illusory direction of peripheral motion is a color-motion feature-binding error. Recent work shows that such binding errors occur even without an exact color match between central and peripheral objects, and, moreover, the frequency of the binding errors in the periphery declines as the chromatic difference increases between the central and peripheral objects [J. Opt. Soc. Am. A 31, A60 (2014)]. This change in the frequency of binding errors with the chromatic difference raises the general question of the chromatic representation from which the difference is determined. Here, basic properties of the chromatic representation are tested to discover whether it depends on independent chromatic differences on the l and the s cardinal axes or, alternatively, on a more specific higher-order chromatic representation. Experimental tests compared the rate of feature-binding errors when the central and peripheral colors had the identical s chromaticity (so zero difference in s) and a fixed magnitude of l difference, while varying the identical s level in center and periphery (thus always keeping the s difference at zero). A chromatic representation based on independent l and s differences would result in the same frequency of color-motion binding errors at every s level. The results are contrary to this prediction, thus showing that the chromatic representation at the level of color-motion feature binding depends on a higherorder chromatic mechanism. PMID:26974945

Feature-Selective Attentional Modulations in Human Frontoparietal Cortex.

PubMed

Ester, Edward F; Sutterer, David W; Serences, John T; Awh, Edward

2016-08-03

Control over visual selection has long been framed in terms of a dichotomy between "source" and "site," where top-down feedback signals originating in frontoparietal cortical areas modulate or bias sensory processing in posterior visual areas. This distinction is motivated in part by observations that frontoparietal cortical areas encode task-level variables (e.g., what stimulus is currently relevant or what motor outputs are appropriate), while posterior sensory areas encode continuous or analog feature representations. Here, we present evidence that challenges this distinction. We used fMRI, a roving searchlight analysis, and an inverted encoding model to examine representations of an elementary feature property (orientation) across the entire human cortical sheet while participants attended either the orientation or luminance of a peripheral grating. Orientation-selective representations were present in a multitude of visual, parietal, and prefrontal cortical areas, including portions of the medial occipital cortex, the lateral parietal cortex, and the superior precentral sulcus (thought to contain the human homolog of the macaque frontal eye fields). Additionally, representations in many-but not all-of these regions were stronger when participants were instructed to attend orientation relative to luminance. Collectively, these findings challenge models that posit a strict segregation between sources and sites of attentional control on the basis of representational properties by demonstrating that simple feature values are encoded by cortical regions throughout the visual processing hierarchy, and that representations in many of these areas are modulated by attention. Influential models of visual attention posit a distinction between top-down control and bottom-up sensory processing networks. These models are motivated in part by demonstrations showing that frontoparietal cortical areas associated with top-down control represent abstract or categorical stimulus information, while visual areas encode parametric feature information. Here, we show that multivariate activity in human visual, parietal, and frontal cortical areas encode representations of a simple feature property (orientation). Moreover, representations in several (though not all) of these areas were modulated by feature-based attention in a similar fashion. These results provide an important challenge to models that posit dissociable top-down control and sensory processing networks on the basis of representational properties. Copyright © 2016 the authors 0270-6474/16/368188-12$15.00/0.

Representational Technologies and Learner Problem-Solving Strategies in Chemistry

ERIC Educational Resources Information Center

McCollum, Brett; Sepulveda, Ana; Moreno, Yuritzel

2016-01-01

Learning within the sciences is often considered through a quantitative lens, but acquiring proficiency with the symbolic representations in chemistry is arguably more akin to language learning. Representational competencies are central to successful communication of chemical information including molecular composition, structure, and properties.…

Perceptual priming versus explicit memory: dissociable neural correlates at encoding.

PubMed

Schott, Björn; Richardson-Klavehn, Alan; Heinze, Hans-Jochen; Düzel, Emrah

2002-05-15

We addressed the hypothesis that perceptual priming and explicit memory have distinct neural correlates at encoding. Event-related potentials (ERPs) were recorded while participants studied visually presented words at deep versus shallow levels of processing (LOPs). The ERPs were sorted by whether or not participants later used studied words as completions to three-letter word stems in an intentional memory test, and by whether or not they indicated that these completions were remembered from the study list. Study trials from which words were later used and not remembered (primed trials) and study trials from which words were later used and remembered (remembered trials) were compared to study trials from which words were later not used (forgotten trials), in order to measure the ERP difference associated with later memory (DM effect). Primed trials involved an early (200-450 msec) centroparietal negative-going DM effect. Remembered trials involved a late (900-1200 msec) right frontal, positive-going DM effect regardless of LOP, as well as an earlier (600-800 msec) central, positive-going DM effect during shallow study processing only. All three DM effects differed topographically, and, in terms of their onset or duration, from the extended (600-1200 msec) fronto-central, positive-going shift for deep compared with shallow study processing. The results provide the first clear evidence that perceptual priming and explicit memory have distinct neural correlates at encoding, consistent with Tulving and Schacter's (1990) distinction between brain systems concerned with perceptual representation versus semantic and episodic memory. They also shed additional light on encoding processes associated with later explicit memory, by suggesting that brain processes influenced by LOP set the stage for other, at least partially separable, brain processes that are more directly related to encoding success.

The Effect of Sexual Experience on the Social Representation of Sex in Portuguese Young Adults.

PubMed

Gomes, Alexandra; Nunes, Cristina

2014-04-26

This study aimed to observe the effect of sexual experience on the social representation of sex in Portuguese young adults. According to social representation theory, the central core of the social representation should be the same in all individuals that share a common social ground, however differences should be found in the peripheral system. It was used a free evocation task to assess the social representation of sex in Portuguese individuals aging between 18 and 25 years old. Nine hundred and sixty individuals were grouped by their sexual experience and condom use habits. A prototypical analysis was conducted to assess the structure of the social representation and statistical differences were analyzed using the qui-square independency test to search for an association between the structure and the group evoking it. The results supported the hypothesis of a common central core for all groups that shows a romanticized vision of sex. The differences found in the peripheral system suggest that sexual experience affects the representation of sex in a way that seems clearer to these individuals the necessity of protection when it comes to sex.

Comparative study of representations of professional autonomy produced by first and last-period undergraduate nursing students 1

PubMed Central

dos Santos, Érick Igor; Gomes, Antonio Marcos Tosoli; Marques, Sergio Corrêa; Ramos, Raquel de Souza; da Silva, Aline Cerqueira Santos Santana; de Oliveira, Francimar Tinoco

2017-01-01

ABSTRACT Objective: to compare the social representations of professional nurse autonomy produced by first and last-period undergraduate nursing students. Method: qualitative, descriptive and exploratory study, based on the structural approach of social representations, the Central Core Theory, carried out with 171 students from three federal public universities, using the free association technique on the object “professional nurse autonomy”. The data were submitted to EVOC 2005 software and to similarity analysis. Results: care was the central core of the representational structure identified among the students of the first period. Among last-period students, knowledge stood out as a core element. The term responsibility was identified as common to both central cores. Conclusion: regarding professional autonomy, the results point to an overlapping process of the reified and consensual universes during the undergraduate course. However, responsibility, inherent in the profession, remains cross-sectional. For the first period students, autonomy is resignified in a practical and attitudinal way, whereas for the last period students, the knowledge acquired stimulates them to assign meaning to professional autonomy with a cognitive and attitudinal representation. The data can support the use of innovative teaching practices in nursing undergraduate courses.

Biological origins of color categorization.

PubMed

Skelton, Alice E; Catchpole, Gemma; Abbott, Joshua T; Bosten, Jenny M; Franklin, Anna

2017-05-23

The biological basis of the commonality in color lexicons across languages has been hotly debated for decades. Prior evidence that infants categorize color could provide support for the hypothesis that color categorization systems are not purely constructed by communication and culture. Here, we investigate the relationship between infants' categorization of color and the commonality across color lexicons, and the potential biological origin of infant color categories. We systematically mapped infants' categorical recognition memory for hue onto a stimulus array used previously to document the color lexicons of 110 nonindustrialized languages. Following familiarization to a given hue, infants' response to a novel hue indicated that their recognition memory parses the hue continuum into red, yellow, green, blue, and purple categories. Infants' categorical distinctions aligned with common distinctions in color lexicons and are organized around hues that are commonly central to lexical categories across languages. The boundaries between infants' categorical distinctions also aligned, relative to the adaptation point, with the cardinal axes that describe the early stages of color representation in retinogeniculate pathways, indicating that infant color categorization may be partly organized by biological mechanisms of color vision. The findings suggest that color categorization in language and thought is partially biologically constrained and have implications for broader debate on how biology, culture, and communication interact in human cognition.

Biological origins of color categorization

PubMed Central

Catchpole, Gemma; Abbott, Joshua T.; Bosten, Jenny M.; Franklin, Anna

2017-01-01

The biological basis of the commonality in color lexicons across languages has been hotly debated for decades. Prior evidence that infants categorize color could provide support for the hypothesis that color categorization systems are not purely constructed by communication and culture. Here, we investigate the relationship between infants’ categorization of color and the commonality across color lexicons, and the potential biological origin of infant color categories. We systematically mapped infants’ categorical recognition memory for hue onto a stimulus array used previously to document the color lexicons of 110 nonindustrialized languages. Following familiarization to a given hue, infants’ response to a novel hue indicated that their recognition memory parses the hue continuum into red, yellow, green, blue, and purple categories. Infants’ categorical distinctions aligned with common distinctions in color lexicons and are organized around hues that are commonly central to lexical categories across languages. The boundaries between infants’ categorical distinctions also aligned, relative to the adaptation point, with the cardinal axes that describe the early stages of color representation in retinogeniculate pathways, indicating that infant color categorization may be partly organized by biological mechanisms of color vision. The findings suggest that color categorization in language and thought is partially biologically constrained and have implications for broader debate on how biology, culture, and communication interact in human cognition. PMID:28484022

The Development of Children's Knowledge About the Appearance-Reality Distinction.

ERIC Educational Resources Information Center

Flavell, John H.

1986-01-01

Summarizes recent research which attempted to discover what children of different ages know about the appearance-reality distinction and related phenomena. Findings show that what helps children grasp the distinction is an increased cognizance of the fact that people are sentient subjects who have mental representations of objects and events. (PS)

Development of common neural representations for distinct numerical problems

PubMed Central

Chang, Ting-Ting; Rosenberg-Lee, Miriam; Metcalfe, Arron W. S.; Chen, Tianwen; Menon, Vinod

2015-01-01

How the brain develops representations for abstract cognitive problems is a major unaddressed question in neuroscience. Here we tackle this fundamental question using arithmetic problem solving, a cognitive domain important for the development of mathematical reasoning. We first examined whether adults demonstrate common neural representations for addition and subtraction problems, two complementary arithmetic operations that manipulate the same quantities. We then examined how the common neural representations for the two problem types change with development. Whole-brain multivoxel representational similarity (MRS) analysis was conducted to examine common coding of addition and subtraction problems in children and adults. We found that adults exhibited significant levels of MRS between the two problem types, not only in the intra-parietal sulcus (IPS) region of the posterior parietal cortex (PPC), but also in ventral temporal-occipital, anterior temporal and dorsolateral prefrontal cortices. Relative to adults, children showed significantly reduced levels of MRS in these same regions. In contrast, no brain areas showed significantly greater MRS between problem types in children. Our findings provide novel evidence that the emergence of arithmetic problem solving skills from childhood to adulthood is characterized by maturation of common neural representations between distinct numerical operations, and involve distributed brain regions important for representing and manipulating numerical quantity. More broadly, our findings demonstrate that representational analysis provides a powerful approach for uncovering fundamental mechanisms by which children develop proficiencies that are a hallmark of human cognition. PMID:26160287

Representational Issues in Students Learning about Evaporation

ERIC Educational Resources Information Center

Tytler, Russell; Prain, Vaughan; Peterson, Suzanne

2007-01-01

This study draws on recent research on the central role of representation in learning. While there has been considerable research on students' understanding of evaporation, the representational issues entailed in this understanding have not been investigated in depth. The study explored students' engagement with evaporation phenomena through…

Australian Indigenous Higher Education: Politics, Policy and Representation

ERIC Educational Resources Information Center

Wilson, Katie; Wilks, Judith

2015-01-01

The growth of Aboriginal and Torres Strait Islander participation in Australian higher education from 1959 to the present is notable statistically, but below population parity. Distinct patterns in government policy-making and programme development, inconsistent funding and political influences, together with Indigenous representation during the…

Evaluation of Chemical Representations in Physical Chemistry Textbooks

ERIC Educational Resources Information Center

Nyachwaya, James M.; Wood, Nathan B.

2014-01-01

That different levels of representation are important for complete understanding of chemistry is an accepted fact in the chemistry education community. This study sought to uncover types of representations used in given physical chemistry textbooks. Textbooks play a central role in the teaching and learning of science (chemistry), and in some…

Examining the Task and Knowledge Demands Needed to Teach with Representations

ERIC Educational Resources Information Center

Mitchell, Rebecca; Charalambous, Charalambos Y.; Hill, Heather C.

2014-01-01

Representations are often used in instruction to highlight key mathematical ideas and support student learning. Despite their centrality in scaffolding teaching and learning, most of our understanding about the tasks involved with using representations in instruction and the knowledge requirements imposed on teachers when using these aids is…

Color-motion feature-binding errors are mediated by a higher-order chromatic representation.

PubMed

Shevell, Steven K; Wang, Wei

2016-03-01

Peripheral and central moving objects of the same color may be perceived to move in the same direction even though peripheral objects have a different true direction of motion [Nature429, 262 (2004)10.1038/429262a]. The perceived, illusory direction of peripheral motion is a color-motion feature-binding error. Recent work shows that such binding errors occur even without an exact color match between central and peripheral objects, and, moreover, the frequency of the binding errors in the periphery declines as the chromatic difference increases between the central and peripheral objects [J. Opt. Soc. Am. A31, A60 (2014)JOAOD60740-323210.1364/JOSAA.31.000A60]. This change in the frequency of binding errors with the chromatic difference raises the general question of the chromatic representation from which the difference is determined. Here, basic properties of the chromatic representation are tested to discover whether it depends on independent chromatic differences on the l and the s cardinal axes or, alternatively, on a more specific higher-order chromatic representation. Experimental tests compared the rate of feature-binding errors when the central and peripheral colors had the identical s chromaticity (so zero difference in s) and a fixed magnitude of l difference, while varying the identical s level in center and periphery (thus always keeping the s difference at zero). A chromatic representation based on independent l and s differences would result in the same frequency of color-motion binding errors at everyslevel. The results are contrary to this prediction, thus showing that the chromatic representation at the level of color-motion feature binding depends on a higher-order chromatic mechanism.

On Productive Knowledge and Levels of Questions.

ERIC Educational Resources Information Center

Andre, Thomas

A model is proposed for memory that stresses a distinction between episodic memory for encoded personal experience and semantic memory for abstractors and generalizations. Basically, the model holds that questions influence the nature of memory representations formed during instruction, and that memory representation controls the way in which…

Cortical Representations of Speech in a Multitalker Auditory Scene.

PubMed

Puvvada, Krishna C; Simon, Jonathan Z

2017-09-20

The ability to parse a complex auditory scene into perceptual objects is facilitated by a hierarchical auditory system. Successive stages in the hierarchy transform an auditory scene of multiple overlapping sources, from peripheral tonotopically based representations in the auditory nerve, into perceptually distinct auditory-object-based representations in the auditory cortex. Here, using magnetoencephalography recordings from men and women, we investigate how a complex acoustic scene consisting of multiple speech sources is represented in distinct hierarchical stages of the auditory cortex. Using systems-theoretic methods of stimulus reconstruction, we show that the primary-like areas in the auditory cortex contain dominantly spectrotemporal-based representations of the entire auditory scene. Here, both attended and ignored speech streams are represented with almost equal fidelity, and a global representation of the full auditory scene with all its streams is a better candidate neural representation than that of individual streams being represented separately. We also show that higher-order auditory cortical areas, by contrast, represent the attended stream separately and with significantly higher fidelity than unattended streams. Furthermore, the unattended background streams are more faithfully represented as a single unsegregated background object rather than as separated objects. Together, these findings demonstrate the progression of the representations and processing of a complex acoustic scene up through the hierarchy of the human auditory cortex. SIGNIFICANCE STATEMENT Using magnetoencephalography recordings from human listeners in a simulated cocktail party environment, we investigate how a complex acoustic scene consisting of multiple speech sources is represented in separate hierarchical stages of the auditory cortex. We show that the primary-like areas in the auditory cortex use a dominantly spectrotemporal-based representation of the entire auditory scene, with both attended and unattended speech streams represented with almost equal fidelity. We also show that higher-order auditory cortical areas, by contrast, represent an attended speech stream separately from, and with significantly higher fidelity than, unattended speech streams. Furthermore, the unattended background streams are represented as a single undivided background object rather than as distinct background objects. Copyright © 2017 the authors 0270-6474/17/379189-08$15.00/0.

From knowledge presentation to knowledge representation to knowledge construction: Future directions for hypermedia

NASA Technical Reports Server (NTRS)

Palumbo, David B.

1990-01-01

Relationships between human memory systems and hypermedia systems are discussed with particular emphasis on the underlying importance of associational memory. The distinctions between knowledge presentation, knowledge representation, and knowledge constructions are addressed. Issues involved in actually developing individualizable hypermedia based knowledge construction tools are presented.

The Contribution of Non-Representational Theories in Education: Some Affective, Ethical and Political Implications

ERIC Educational Resources Information Center

Zembylas, Michalinos

2017-01-01

This paper follows recent debates around theorizations of "affect" and its distinction from "emotion" in the context of non-representational theories (NRT) to exemplify how the ontologization of affects creates important openings of ethical and political potential in educators' efforts to make productive interventions in…

Deconstructing the relationships between phylogenetic diversity and ecology: a case study on ecosystem functioning.

PubMed

Davies, T Jonathan; Urban, Mark C; Rayfield, Bronwyn; Cadotte, Marc W; Peres-Neto, Pedro R

2016-09-01

Recent studies have supported a link between phylogenetic diversity and various ecological properties including ecosystem function. However, such studies typically assume that phylogenetic branches of equivalent length are more or less interchangeable. Here we suggest that there is a need to consider not only branch lengths but also their placement on the phylogeny. We demonstrate how two common indices of network centrality can be used to describe the evolutionary distinctiveness of network elements (nodes and branches) on a phylogeny. If phylogenetic diversity enhances ecosystem function via complementarity and the representation of functional diversity, we would predict a correlation between evolutionary distinctiveness of network elements and their contribution to ecosystem process. In contrast, if one or a few evolutionary innovations play key roles in ecosystem function, the relationship between evolutionary distinctiveness and functional contribution may be weak or absent. We illustrate how network elements associated with high functional contribution can be identified from regressions between phylogenetic diversity and productivity using a well-known empirical data set on plant productivity from the Cedar Creek Long-Term Ecological Research. We find no association between evolutionary distinctiveness and ecosystem functioning, but we are able to identify phylogenetic elements associated with species of known high functional contribution within the Fabaceae. Our perspective provides a useful guide in the search for ecological traits linking diversity and ecosystem function, and suggests a more nuanced consideration of phylogenetic diversity is required in the conservation and biodiversity-ecosystem-function literature. © 2016 by the Ecological Society of America.

Benchmarking Ontologies: Bigger or Better?

PubMed Central

Yao, Lixia; Divoli, Anna; Mayzus, Ilya; Evans, James A.; Rzhetsky, Andrey

2011-01-01

A scientific ontology is a formal representation of knowledge within a domain, typically including central concepts, their properties, and relations. With the rise of computers and high-throughput data collection, ontologies have become essential to data mining and sharing across communities in the biomedical sciences. Powerful approaches exist for testing the internal consistency of an ontology, but not for assessing the fidelity of its domain representation. We introduce a family of metrics that describe the breadth and depth with which an ontology represents its knowledge domain. We then test these metrics using (1) four of the most common medical ontologies with respect to a corpus of medical documents and (2) seven of the most popular English thesauri with respect to three corpora that sample language from medicine, news, and novels. Here we show that our approach captures the quality of ontological representation and guides efforts to narrow the breach between ontology and collective discourse within a domain. Our results also demonstrate key features of medical ontologies, English thesauri, and discourse from different domains. Medical ontologies have a small intersection, as do English thesauri. Moreover, dialects characteristic of distinct domains vary strikingly as many of the same words are used quite differently in medicine, news, and novels. As ontologies are intended to mirror the state of knowledge, our methods to tighten the fit between ontology and domain will increase their relevance for new areas of biomedical science and improve the accuracy and power of inferences computed across them. PMID:21249231

Sequence analysis by iterated maps, a review.

PubMed

Almeida, Jonas S

2014-05-01

Among alignment-free methods, Iterated Maps (IMs) are on a particular extreme: they are also scale free (order free). The use of IMs for sequence analysis is also distinct from other alignment-free methodologies in being rooted in statistical mechanics instead of computational linguistics. Both of these roots go back over two decades to the use of fractal geometry in the characterization of phase-space representations. The time series analysis origin of the field is betrayed by the title of the manuscript that started this alignment-free subdomain in 1990, 'Chaos Game Representation'. The clash between the analysis of sequences as continuous series and the better established use of Markovian approaches to discrete series was almost immediate, with a defining critique published in same journal 2 years later. The rest of that decade would go by before the scale-free nature of the IM space was uncovered. The ensuing decade saw this scalability generalized for non-genomic alphabets as well as an interest in its use for graphic representation of biological sequences. Finally, in the past couple of years, in step with the emergence of BigData and MapReduce as a new computational paradigm, there is a surprising third act in the IM story. Multiple reports have described gains in computational efficiency of multiple orders of magnitude over more conventional sequence analysis methodologies. The stage appears to be now set for a recasting of IMs with a central role in processing nextgen sequencing results.

Mental Representation in The Thought of Sidney Blatt: Developmental Processes.

PubMed

Auerbach, John S; Diamond, Diana

2017-06-01

Mental representation was a central construct in Sidney Blatt's contributions to psychology and psychoanalysis. This brief review demonstrates that Blatt's understanding of representation was always informed by basic psychoanalytic concepts like the centrality of early caregiver-infant relationships and of unconscious mental processes. Although Blatt's earlier writings were informed by psychoanalytic ego psychology and Piagetian cognitive developmental psychology, they focused nonetheless on how an individual uses bodily and relational experiences to construct an object world; they also consistently presented object representations as having significant unconscious dimensions. From the mid-1980s onward, Blatt's contributions, in dialogue with his many students, moved in an even more experiential/relational direction and manifested the influence of attachment theory, parent-infant interaction research, and intersubjectivity theory. They also incorporated contemporary cognitive psychology, with its emphasis on implicit or procedural, rather than explicit, dimensions as a means of accounting for aspects of object representations that are not in conscious awareness. Throughout his career, however, Blatt regarded mental representation as the construct that mediates between the child's earliest bodily and relational experiences and the mature adult's symbolic, most emotionally profound capacities.

Illusions of having small or large invisible bodies influence visual perception of object size

PubMed Central

van der Hoort, Björn; Ehrsson, H. Henrik

2016-01-01

The size of our body influences the perceived size of the world so that objects appear larger to children than to adults. The mechanisms underlying this effect remain unclear. It has been difficult to dissociate visual rescaling of the external environment based on an individual’s visible body from visual rescaling based on a central multisensory body representation. To differentiate these potential causal mechanisms, we manipulated body representation without a visible body by taking advantage of recent developments in body representation research. Participants experienced the illusion of having a small or large invisible body while object-size perception was tested. Our findings show that the perceived size of test-objects was determined by the size of the invisible body (inverse relation), and by the strength of the invisible body illusion. These findings demonstrate how central body representation directly influences visual size perception, without the need for a visible body, by rescaling the spatial representation of the environment. PMID:27708344

Controversies in Narcissism.

PubMed

Miller, Joshua D; Lynam, Donald R; Hyatt, Courtland S; Campbell, W Keith

2017-05-08

There has been a surge in interest in and research on narcissism and narcissistic personality disorder (NPD). Despite or because of this increased attention, there are several areas of substantial debate that surround the construct, including descriptions of grandiose and vulnerable dimensions or variants, questions regarding the existence of a consensual description, central versus peripheral features of narcissism, distinctions between normal and pathological narcissism, possible etiological factors, the role of self-esteem in narcissism, where narcissism should be studied, how it can be assessed, and its representation in diagnostic nosologies. We suggest that a failure to distinguish between grandiose (i.e., overtly immodest, self-centered, entitled, domineering) and vulnerable (e.g., self-centered, distrustful, neurotic, introverted) presentations of narcissism has led to a less cohesive and coherent literature and that trait-based models of personality and personality disorder can bring greater clarity to many of these important debates.

Relationship among Environmental Pointing Accuracy, Mental Rotation, Sex, and Hormones

ERIC Educational Resources Information Center

Bell, Scott; Saucier, Deborah

2004-01-01

Humans rely on internal representations to solve a variety of spatial problems including navigation. Navigation employs specific information to compose a representation of space that is distinct from that obtained through static bird's-eye or horizontal perspectives. The ability to point to on-route locations, off-route locations, and the route…

Maternal Identity of Hearing Mothers of Deaf Adolescents. Empirical Studies: An Interpersonal Approach

ERIC Educational Resources Information Center

Kobosko, Joanna; Zalewska, Marina

2011-01-01

The maternal identity of mothers of adolescents who are deaf has certain specific features compared with mothers of adolescents who have typical hearing. That is, maternal identity differs with respect to distinctiveness, self-representation, and representation of mother-child relationships. A study using a comparative paradigm was conducted. The…

Rethinking the Representation Problem in Curriculum Inquiry

ERIC Educational Resources Information Center

Green, Bill

2010-01-01

The consolidation of reconceptualism as a distinctive tradition in curriculum inquiry is commonly understood to go hand-in-hand with the decline and even eclipse of an explicit political orientation in such work. This paper offers an alternative argument, focusing on a re-assessment of what has been called the representation problem, and exploring…

Bilingual Lexical Interactions in an Unsupervised Neural Network Model

ERIC Educational Resources Information Center

Zhao, Xiaowei; Li, Ping

2010-01-01

In this paper we present an unsupervised neural network model of bilingual lexical development and interaction. We focus on how the representational structures of the bilingual lexicons can emerge, develop, and interact with each other as a function of the learning history. The results show that: (1) distinct representations for the two lexicons…

Shared and Distinctive Origins and Correlates of Adult Attachment Representations: The Developmental Organization of Romantic Functioning

ERIC Educational Resources Information Center

Haydon, Katherine C.; Collins, W. A.; Salvatore, Jessica E.; Simpson, Jeffry A.; Roisman, Glenn I.

2012-01-01

To test proposals regarding the hierarchical organization of adult attachment, this study examined developmental origins of generalized and romantic attachment representations and their concurrent associations with romantic functioning. Participants (N = 112) in a 35-year prospective study completed the Adult Attachment Interview (AAI) and Current…

Towards "Inverse" Character Tables? A One-Step Method for Decomposing Reducible Representations

ERIC Educational Resources Information Center

Piquemal, J.-Y.; Losno, R.; Ancian, B.

2009-01-01

In the framework of group theory, a new procedure is described for a one-step automated reduction of reducible representations. The matrix inversion tool, provided by standard spreadsheet software, is applied to the central part of the character table that contains the characters of the irreducible representation. This method is not restricted to…

Visual Memories Bypass Normalization.

PubMed

Bloem, Ilona M; Watanabe, Yurika L; Kibbe, Melissa M; Ling, Sam

2018-05-01

How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores-neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation.

Visual Memories Bypass Normalization

PubMed Central

Bloem, Ilona M.; Watanabe, Yurika L.; Kibbe, Melissa M.; Ling, Sam

2018-01-01

How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores—neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation. PMID:29596038

Distinct but Overlapping Patterns of Response to Words and Faces in the Fusiform Gyrus.

PubMed

Harris, Richard J; Rice, Grace E; Young, Andrew W; Andrews, Timothy J

2016-07-01

Converging evidence suggests that the fusiform gyrus is involved in the processing of both faces and words. We used fMRI to investigate the extent to which the representation of words and faces in this region of the brain is based on a common neural representation. In Experiment 1, a univariate analysis revealed regions in the fusiform gyrus that were only selective for faces and other regions that were only selective for words. However, we also found regions that showed both word-selective and face-selective responses, particularly in the left hemisphere. We then used a multivariate analysis to measure the pattern of response to faces and words. Despite the overlap in regional responses, we found distinct patterns of response to both faces and words in the left and right fusiform gyrus. In Experiment 2, fMR adaptation was used to determine whether information about familiar faces and names is integrated in the fusiform gyrus. Distinct regions of the fusiform gyrus showed adaptation to either familiar faces or familiar names. However, there was no adaptation to sequences of faces and names with the same identity. Taken together, these results provide evidence for distinct, but overlapping, neural representations for words and faces in the fusiform gyrus. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

A Cross-Modal Perspective on the Relationships between Imagery and Working Memory

PubMed Central

Likova, Lora T.

2013-01-01

Mapping the distinctions and interrelationships between imagery and working memory (WM) remains challenging. Although each of these major cognitive constructs is defined and treated in various ways across studies, most accept that both imagery and WM involve a form of internal representation available to our awareness. In WM, there is a further emphasis on goal-oriented, active maintenance, and use of this conscious representation to guide voluntary action. Multicomponent WM models incorporate representational buffers, such as the visuo-spatial sketchpad, plus central executive functions. If there is a visuo-spatial “sketchpad” for WM, does imagery involve the same representational buffer? Alternatively, does WM employ an imagery-specific representational mechanism to occupy our awareness? Or do both constructs utilize a more generic “projection screen” of an amodal nature? To address these issues, in a cross-modal fMRI study, I introduce a novel Drawing-Based Memory Paradigm, and conceptualize drawing as a complex behavior that is readily adaptable from the visual to non-visual modalities (such as the tactile modality), which opens intriguing possibilities for investigating cross-modal learning and plasticity. Blindfolded participants were trained through our Cognitive-Kinesthetic Method (Likova, 2010a, 2012) to draw complex objects guided purely by the memory of felt tactile images. If this WM task had been mediated by transfer of the felt spatial configuration to the visual imagery mechanism, the response-profile in visual cortex would be predicted to have the “top-down” signature of propagation of the imagery signal downward through the visual hierarchy. Remarkably, the pattern of cross-modal occipital activation generated by the non-visual memory drawing was essentially the inverse of this typical imagery signature. The sole visual hierarchy activation was isolated to the primary visual area (V1), and accompanied by deactivation of the entire extrastriate cortex, thus ’cutting-off’ any signal propagation from/to V1 through the visual hierarchy. The implications of these findings for the debate on the interrelationships between the core cognitive constructs of WM and imagery and the nature of internal representations are evaluated. PMID:23346061

Object similarity affects the perceptual strategy underlying invariant visual object recognition in rats

PubMed Central

Rosselli, Federica B.; Alemi, Alireza; Ansuini, Alessio; Zoccolan, Davide

2015-01-01

In recent years, a number of studies have explored the possible use of rats as models of high-level visual functions. One central question at the root of such an investigation is to understand whether rat object vision relies on the processing of visual shape features or, rather, on lower-order image properties (e.g., overall brightness). In a recent study, we have shown that rats are capable of extracting multiple features of an object that are diagnostic of its identity, at least when those features are, structure-wise, distinct enough to be parsed by the rat visual system. In the present study, we have assessed the impact of object structure on rat perceptual strategy. We trained rats to discriminate between two structurally similar objects, and compared their recognition strategies with those reported in our previous study. We found that, under conditions of lower stimulus discriminability, rat visual discrimination strategy becomes more view-dependent and subject-dependent. Rats were still able to recognize the target objects, in a way that was largely tolerant (i.e., invariant) to object transformation; however, the larger structural and pixel-wise similarity affected the way objects were processed. Compared to the findings of our previous study, the patterns of diagnostic features were: (i) smaller and more scattered; (ii) only partially preserved across object views; and (iii) only partially reproducible across rats. On the other hand, rats were still found to adopt a multi-featural processing strategy and to make use of part of the optimal discriminatory information afforded by the two objects. Our findings suggest that, as in humans, rat invariant recognition can flexibly rely on either view-invariant representations of distinctive object features or view-specific object representations, acquired through learning. PMID:25814936

[Multifaceted body. I. The bodies of medicine].

PubMed

Saraga, M; Bourquin, C; Wykretowicz, H; Stiefel, F

2015-02-11

The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This first article discusses four distinct types of representation of the body within medicine, each related to a specific epistemology and shaping a distinct kind of clinical legitimacy: the body-object of anatomy, the body-machine of physiology, the cybernetic body of biology, the statistical body of epidemiology.

Music as Environment: An Ecological and Biosemiotic Approach

PubMed Central

Reybrouck, Mark

2014-01-01

This paper provides an attempt to conceive of music in terms of a sounding environment. Starting from a definition of music as a collection of vibrational events, it introduces the distinction between discrete-symbolic representations as against analog-continuous representations of the sounds. The former makes it possible to conceive of music in terms of a Humboldt system, the latter in terms of an experiential approach. Both approaches, further, are not opposed to each other, but are complementary to some extent. There is, however, a distinction to be drawn between the bottom-up approach to auditory processing of environmental sounds and music, which is continuous and proceeding in real time, as against the top-down approach, which is proceeding at a level of mental representation by applying discrete symbolic labels to vibrational events. The distinction is discussed against the background of phylogenetic and ontogenetic claims, with a major focus on the innate auditory capabilities of the fetus and neonate and the gradual evolution from mere sensory perception of sound to sense-making and musical meaning. The latter, finally, is elaborated on the basis of the operational concepts of affordance and functional tone, thus bringing together some older contributions from ecology and biosemiotics. PMID:25545707

Strategy Revealing Phenotypic Differences among Synthetic Oscillator Designs

PubMed Central

2015-01-01

Considerable progress has been made in identifying and characterizing the component parts of genetic oscillators, which play central roles in all organisms. Nonlinear interaction among components is sufficiently complex that mathematical models are required to elucidate their elusive integrated behavior. Although natural and synthetic oscillators exhibit common architectures, there are numerous differences that are poorly understood. Utilizing synthetic biology to uncover basic principles of simpler circuits is a way to advance understanding of natural circadian clocks and rhythms. Following this strategy, we address the following questions: What are the implications of different architectures and molecular modes of transcriptional control for the phenotypic repertoire of genetic oscillators? Are there designs that are more realizable or robust? We compare synthetic oscillators involving one of three architectures and various combinations of the two modes of transcriptional control using a methodology that provides three innovations: a rigorous definition of phenotype, a procedure for deconstructing complex systems into qualitatively distinct phenotypes, and a graphical representation for illuminating the relationship between genotype, environment, and the qualitatively distinct phenotypes of a system. These methods provide a global perspective on the behavioral repertoire, facilitate comparisons of alternatives, and assist the rational design of synthetic gene circuitry. In particular, the results of their application here reveal distinctive phenotypes for several designs that have been studied experimentally as well as a best design among the alternatives that has yet to be constructed and tested. PMID:25019938

BeeSign: A Computationally-Mediated Intervention to Examine K-1 Students' Representational Activities in the Context of Teaching Complex Systems Concepts

ERIC Educational Resources Information Center

Danish, Joshua Adam

2009-01-01

Representations such as drawings, graphs, and computer simulations, are central to learning and doing science. Furthermore, ongoing success in science learning requires students to build on the representations and associated practices that they are presumed to have learned throughout their schooling career. Without these practices, students have…

Evidence for a Non-Linguistic Distinction between Singular and Plural Sets in Rhesus Monkeys

ERIC Educational Resources Information Center

Barner, David; Wood, Justin; Hauser, Marc; Carey, Susan

2008-01-01

Set representations are explicitly expressed in natural language. For example, many languages distinguish between sets and subsets ("all" vs. "some"), as well as between singular and plural sets ("a cat" vs. "some cats"). Three experiments explored the hypothesis that these representations are language specific, and thus absent from the conceptual…

The Dangers of Playing Dress-Up: Popular Representations of Jessica Lynch and the Controversy Regarding Women in Combat

ERIC Educational Resources Information Center

Holland, Shannon L.

2006-01-01

Through a critical analysis of the public discourse surrounding the capture and rescue of Jessica Lynch, this essay investigates how Lynch's body "comes to matter" in political debates regarding women in combat. This article argues that popular representations of Lynch's natural femaleness rearticulate the seemingly biological distinctions between…

On the Road: Examining Self-Representation and Discourses of Homelessness in Young Adult Texts

ERIC Educational Resources Information Center

Rogers, Theresa; Marshall, Elizabeth

2012-01-01

In this article, the authors analyze representations of social issues within contemporary memoirs written for and marketed to a young adult audience and multimodal zines produced by homeless youth. To read across these distinctly different texts (mass marketed and do-it-yourself cultural productions) and genres (memoir and zines), the authors…

Factors Contributing to under Representation of Female Teachers in Headship Positions in Primary Schools in Eldoret Municipality, Kenya

ERIC Educational Resources Information Center

Barmao, Catherine

2013-01-01

This paper analyses factors contributing to under representation of female teachers in headship positions in Eldoret Municipality Kenya. The study was guided by socialization theory to hierarchical gender prescriptions which gave three distinct theoretical traditions that help, understand sex and gender. Descriptive survey was adopted for the…

[Social representations of illness: Comparison of "expert" knowledge and "naïve" knowledge].

PubMed

Jeoffrion, C; Dupont, P; Tripodi, D; Roland-Lévy, C

2016-06-01

The link between social practices and representations is now well known. But while many studies have focused on the social representation of mental illness, in various populations, few studies have focused on the notion of disease/illness by comparing professionals and non-professionals health workers representations. Indeed, the disease is both a reality described, explained and treated by medicine; for those who are affected by a disease, it is an individual experience with psychological, social and cultural impacts. The social representation is determined by the structure of the social groups in which it develops; therefore, it is a form of knowledge socially shaped and shared by the members of a social group. Several theoretical extensions have been elaborated and particularly, the structural approach and the central core theory. These approaches sustain the arguments of a hierarchical organization of a social representation with a central core surrounded by peripheral zones. The central core is common and shared by the majority of the members of a given group, whereas the peripheral zones provide space for the individualization of the social knowledge. The main goal of our study is to highlight the social representations of disease in health professionals (HP) and in non-health professionals (NHP). The group of HP has been differentiated into three subgroups: "medical doctors", "nurses" and "pharmacists", while that of NHP in two subgroups: those submitted to a "long period medical treatment" and those "without treatment". Our aim is to show that there are different social and professional Representations of disease. The professional representations are specific social representations related to professional contexts. We formulate the following assumptions (a) that the social representations of HP and NHP will be articulated around a common central core. Nevertheless, we expect to find specific peripheral elements related to professional status, based on different knowledge and a differentiated "practice"; (b) the HP should refer to more descriptive aspects of the disease and monitoring of patients, while (c) NHP should refer more to the experience of illness around emotional aspects. Our sample is composed of 270 participants (135 HP and 135 HNP). Representations are measured by a free association task based on the target term: disease. The data have been submitted to prototypical and categorical analyses in agreement with the central core theory. The results confirm that there is a common social representation of disease shared by the two groups, which refers essentially to suffering and pain. The analysis of each group brings to light two different registers: the one of the HP with more descriptive words referring to the nature and the illness's characteristics, and the other ones of the HNP with more words connected to emotions and referring to personal real experience of the illness. As expected, the social representation of the HP is referring to the "professional representations" of the disease, while the one for the HNP is linked to "practices" of an illness. An analysis of intra-group differences shows specificities for each of the questioned subgroups. In the HP, medical doctors focus on the diagnosis and consequences of the disease, pharmacists refer to the treatment of the disease and its management, while nurses focus on the treatment and on the relation while monitoring patients. In the NHP, people submitted to a "long period medical treatment" refer to the emotional aspects and to the consequences of the illness on their live, while those without treatment use more descriptive and formal terms. These results suggest to the PS to expand exchanges related to the disease in order to facilitate communication centered on taking care of the patient, considered in its wholeness and not only as an actual or potential patient. This is an important step in improving the health of the patient. Copyright © 2015 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.

Role of Importance and Distinctiveness of Semantic Features in People with Aphasia: A Replication Study

ERIC Educational Resources Information Center

Mason-Baughman, Mary Beth; Wallace, Sarah E.

2014-01-01

Previous studies suggest that people with aphasia have incomplete lexical-semantic representations with decreased low-importance distinctive (LID) feature knowledge. In addition, decreased LID feature knowledge correlates with ability to discriminate among semantically related words. The current study seeks to replicate and extend previous…

Neural Network of Body Representation Differs between Transsexuals and Cissexuals

PubMed Central

Lin, Chia-Shu; Ku, Hsiao-Lun; Chao, Hsiang-Tai; Tu, Pei-Chi; Li, Cheng-Ta; Cheng, Chou-Ming; Su, Tung-Ping; Lee, Ying-Chiao; Hsieh, Jen-Chuen

2014-01-01

Body image is the internal representation of an individual’s own physical appearance. Individuals with gender identity disorder (GID), commonly referred to as transsexuals (TXs), are unable to form a satisfactory body image due to the dissonance between their biological sex and gender identity. We reasoned that changes in the resting-state functional connectivity (rsFC) network would neurologically reflect such experiential incongruence in TXs. Using graph theory-based network analysis, we investigated the regional changes of the degree centrality of the rsFC network. The degree centrality is an index of the functional importance of a node in a neural network. We hypothesized that three key regions of the body representation network, i.e., the primary somatosensory cortex, the superior parietal lobule and the insula, would show a higher degree centrality in TXs. Twenty-three pre-treatment TXs (11 male-to-female and 12 female-to-male TXs) as one psychosocial group and 23 age-matched healthy cissexual control subjects (CISs, 11 males and 12 females) were recruited. Resting-state functional magnetic resonance imaging was performed, and binarized rsFC networks were constructed. The TXs demonstrated a significantly higher degree centrality in the bilateral superior parietal lobule and the primary somatosensory cortex. In addition, the connectivity between the right insula and the bilateral primary somatosensory cortices was negatively correlated with the selfness rating of their desired genders. These data indicate that the key components of body representation manifest in TXs as critical function hubs in the rsFC network. The negative association may imply a coping mechanism that dissociates bodily emotion from body image. The changes in the functional connectome may serve as representational markers for the dysphoric bodily self of TXs. PMID:24465785

Beyond Natural Numbers: Negative Number Representation in Parietal Cortex

PubMed Central

Blair, Kristen P.; Rosenberg-Lee, Miriam; Tsang, Jessica M.; Schwartz, Daniel L.; Menon, Vinod

2012-01-01

Unlike natural numbers, negative numbers do not have natural physical referents. How does the brain represent such abstract mathematical concepts? Two competing hypotheses regarding representational systems for negative numbers are a rule-based model, in which symbolic rules are applied to negative numbers to translate them into positive numbers when assessing magnitudes, and an expanded magnitude model, in which negative numbers have a distinct magnitude representation. Using an event-related functional magnetic resonance imaging design, we examined brain responses in 22 adults while they performed magnitude comparisons of negative and positive numbers that were quantitatively near (difference <4) or far apart (difference >6). Reaction times (RTs) for negative numbers were slower than positive numbers, and both showed a distance effect whereby near pairs took longer to compare. A network of parietal, frontal, and occipital regions were differentially engaged by negative numbers. Specifically, compared to positive numbers, negative number processing resulted in greater activation bilaterally in intraparietal sulcus (IPS), middle frontal gyrus, and inferior lateral occipital cortex. Representational similarity analysis revealed that neural responses in the IPS were more differentiated among positive numbers than among negative numbers, and greater differentiation among negative numbers was associated with faster RTs. Our findings indicate that despite negative numbers engaging the IPS more strongly, the underlying neural representation are less distinct than that of positive numbers. We discuss our findings in the context of the two theoretical models of negative number processing and demonstrate how multivariate approaches can provide novel insights into abstract number representation. PMID:22363276

Beyond natural numbers: negative number representation in parietal cortex.

PubMed

Blair, Kristen P; Rosenberg-Lee, Miriam; Tsang, Jessica M; Schwartz, Daniel L; Menon, Vinod

2012-01-01

Unlike natural numbers, negative numbers do not have natural physical referents. How does the brain represent such abstract mathematical concepts? Two competing hypotheses regarding representational systems for negative numbers are a rule-based model, in which symbolic rules are applied to negative numbers to translate them into positive numbers when assessing magnitudes, and an expanded magnitude model, in which negative numbers have a distinct magnitude representation. Using an event-related functional magnetic resonance imaging design, we examined brain responses in 22 adults while they performed magnitude comparisons of negative and positive numbers that were quantitatively near (difference <4) or far apart (difference >6). Reaction times (RTs) for negative numbers were slower than positive numbers, and both showed a distance effect whereby near pairs took longer to compare. A network of parietal, frontal, and occipital regions were differentially engaged by negative numbers. Specifically, compared to positive numbers, negative number processing resulted in greater activation bilaterally in intraparietal sulcus (IPS), middle frontal gyrus, and inferior lateral occipital cortex. Representational similarity analysis revealed that neural responses in the IPS were more differentiated among positive numbers than among negative numbers, and greater differentiation among negative numbers was associated with faster RTs. Our findings indicate that despite negative numbers engaging the IPS more strongly, the underlying neural representation are less distinct than that of positive numbers. We discuss our findings in the context of the two theoretical models of negative number processing and demonstrate how multivariate approaches can provide novel insights into abstract number representation.

Direct neural pathways convey distinct visual information to Drosophila mushroom bodies

PubMed Central

Vogt, Katrin; Aso, Yoshinori; Hige, Toshihide; Knapek, Stephan; Ichinose, Toshiharu; Friedrich, Anja B; Turner, Glenn C; Rubin, Gerald M; Tanimoto, Hiromu

2016-01-01

Previously, we demonstrated that visual and olfactory associative memories of Drosophila share mushroom body (MB) circuits (Vogt et al., 2014). Unlike for odor representation, the MB circuit for visual information has not been characterized. Here, we show that a small subset of MB Kenyon cells (KCs) selectively responds to visual but not olfactory stimulation. The dendrites of these atypical KCs form a ventral accessory calyx (vAC), distinct from the main calyx that receives olfactory input. We identified two types of visual projection neurons (VPNs) directly connecting the optic lobes and the vAC. Strikingly, these VPNs are differentially required for visual memories of color and brightness. The segregation of visual and olfactory domains in the MB allows independent processing of distinct sensory memories and may be a conserved form of sensory representations among insects. DOI: http://dx.doi.org/10.7554/eLife.14009.001 PMID:27083044

PhET Interactive Simulations: Transformative Tools for Teaching Chemistry

ERIC Educational Resources Information Center

Moore, Emily B.; Chamberlain, Julia M.; Parson, Robert; Perkins, Katherine K.

2014-01-01

Developing fluency across symbolic-, macroscopic-, and particulate-level representations is central to learning chemistry. Within the chemistry education community, animations and simulations that support multi-representational fluency are considered critical. With advances in the accessibility and sophistication of technology,…

A View of the Neural Representation of Second Language Syntax through Artificial Language Learning under Implicit Contexts of Exposure

ERIC Educational Resources Information Center

Morgan-Short, Kara; Deng, ZhiZhou; Brill-Schuetz, Katherine A.; Faretta- Stutenberg, Mandy; Wong, Patrick C. M.; Wong, Francis C. K.

2015-01-01

The current study aims to make an initial neuroimaging contribution to central implicit-explicit issues in second language (L2) acquisition by considering how implicit and explicit contexts mediate the neural representation of L2. Focusing on implicit contexts, the study employs a longitudinal design to examine the neural representation of L2…

Taste quality decoding parallels taste sensations.

PubMed

Crouzet, Sébastien M; Busch, Niko A; Ohla, Kathrin

2015-03-30

In most species, the sense of taste is key in the distinction of potentially nutritious and harmful food constituents and thereby in the acceptance (or rejection) of food. Taste quality is encoded by specialized receptors on the tongue, which detect chemicals corresponding to each of the basic tastes (sweet, salty, sour, bitter, and savory [1]), before taste quality information is transmitted via segregated neuronal fibers [2], distributed coding across neuronal fibers [3], or dynamic firing patterns [4] to the gustatory cortex in the insula. In rodents, both hardwired coding by labeled lines [2] and flexible, learning-dependent representations [5] and broadly tuned neurons [6] seem to coexist. It is currently unknown how, when, and where taste quality representations are established in the cortex and whether these representations are used for perceptual decisions. Here, we show that neuronal response patterns allow to decode which of four tastants (salty, sweet, sour, and bitter) participants tasted in a given trial by using time-resolved multivariate pattern analyses of large-scale electrophysiological brain responses. The onset of this prediction coincided with the earliest taste-evoked responses originating from the insula and opercular cortices, indicating that quality is among the first attributes of a taste represented in the central gustatory system. These response patterns correlated with perceptual decisions of taste quality: tastes that participants discriminated less accurately also evoked less discriminated brain response patterns. The results therefore provide the first evidence for a link between taste-related decision-making and the predictive value of these brain response patterns. Copyright © 2015 Elsevier Ltd. All rights reserved.

A distinct layer of the medulla integrates sky compass signals in the brain of an insect.

PubMed

el Jundi, Basil; Pfeiffer, Keram; Homberg, Uwe

2011-01-01

Mass migration of desert locusts is a common phenomenon in North Africa and the Middle East but how these insects navigate is still poorly understood. Laboratory studies suggest that locusts are able to exploit the sky polarization pattern as a navigational cue. Like other insects locusts detect polarized light through a specialized dorsal rim area (DRA) of the eye. Polarization signals are transmitted through the optic lobe to the anterior optic tubercle (AOTu) and, finally, to the central complex in the brain. Whereas neurons of the AOTu integrate sky polarization and chromatic cues in a daytime dependent manner, the central complex holds a topographic representation of azimuthal directions suggesting a role as an internal sky compass. To understand further the integration of sky compass cues we studied polarization-sensitive (POL) neurons in the medulla that may be intercalated between DRA photoreceptors and AOTu neurons. Five types of POL-neuron were characterized and four of these in multiple recordings. All neurons had wide arborizations in medulla layer 4 and most, additionally, in the dorsal rim area of the medulla and in the accessory medulla, the presumed circadian clock. The neurons showed type-specific orientational tuning to zenithal polarized light and azimuth tuning to unpolarized green and UV light spots. In contrast to neurons of the AOTu, we found no evidence for color opponency and daytime dependent adjustment of sky compass signals. Therefore, medulla layer 4 is a distinct stage in the integration of sky compass signals that precedes the time-compensated integration of celestial cues in the AOTu.

Neural foundations of overt and covert actions.

PubMed

Simos, Panagiotis G; Kavroulakis, Eleftherios; Maris, Thomas; Papadaki, Efrosini; Boursianis, Themistoklis; Kalaitzakis, Giorgos; Savaki, Helen E

2017-05-15

We used fMRI to assess the human brain areas activated for execution, observation and 1st person motor imagery of a visually guided tracing task with the index finger. Voxel-level conjunction analysis revealed several cortical areas activated in common across all three motor conditions, namely, the upper limb representation of the primary motor and somatosensory cortices, the dorsal and ventral premotor, the superior and inferior parietal cortices as well as the posterior part of the superior and middle temporal gyrus including the temporo-parietal junction (TPj) and the extrastriate body area (EBA). Functional connectivity analyses corroborated the notion that a common sensory-motor fronto-parieto-temporal cortical network is engaged for execution, observation, and imagination of the very same action. Taken together these findings are consistent with the more parsimonious account of motor cognition provided by the mental simulation theory rather than the recently revised mirror neuron view Action imagination and observation were each associated with several additional functional connections, which may serve the distinction between overt action and its covert counterparts, and the attribution of action to the correct agent. For example, the central position of the right middle and inferior frontal gyrus in functional connectivity during motor imagery may reflect the suppression of movements during mere imagination of action, and may contribute to the distinction between 'imagined' and 'real' action. Also, the central role of the right EBA in observation, assessed by functional connectivity analysis, may be related to the attribution of action to the 'external agent' as opposed to the 'self'. Copyright © 2017 Elsevier Inc. All rights reserved.

A Distinct Layer of the Medulla Integrates Sky Compass Signals in the Brain of an Insect

PubMed Central

el Jundi, Basil; Pfeiffer, Keram; Homberg, Uwe

2011-01-01

Mass migration of desert locusts is a common phenomenon in North Africa and the Middle East but how these insects navigate is still poorly understood. Laboratory studies suggest that locusts are able to exploit the sky polarization pattern as a navigational cue. Like other insects locusts detect polarized light through a specialized dorsal rim area (DRA) of the eye. Polarization signals are transmitted through the optic lobe to the anterior optic tubercle (AOTu) and, finally, to the central complex in the brain. Whereas neurons of the AOTu integrate sky polarization and chromatic cues in a daytime dependent manner, the central complex holds a topographic representation of azimuthal directions suggesting a role as an internal sky compass. To understand further the integration of sky compass cues we studied polarization-sensitive (POL) neurons in the medulla that may be intercalated between DRA photoreceptors and AOTu neurons. Five types of POL-neuron were characterized and four of these in multiple recordings. All neurons had wide arborizations in medulla layer 4 and most, additionally, in the dorsal rim area of the medulla and in the accessory medulla, the presumed circadian clock. The neurons showed type-specific orientational tuning to zenithal polarized light and azimuth tuning to unpolarized green and UV light spots. In contrast to neurons of the AOTu, we found no evidence for color opponency and daytime dependent adjustment of sky compass signals. Therefore, medulla layer 4 is a distinct stage in the integration of sky compass signals that precedes the time-compensated integration of celestial cues in the AOTu. PMID:22114712

Binocular pattern deprivation interferes with the expression of proteins involved in primary visual cortex maturation in the cat.

PubMed

Laskowska-Macios, Karolina; Nys, Julie; Hu, Tjing-Tjing; Zapasnik, Monika; Van der Perren, Anke; Kossut, Malgorzata; Burnat, Kalina; Arckens, Lutgarde

2015-08-14

Binocular pattern deprivation from eye opening (early BD) delays the maturation of the primary visual cortex. This delay is more pronounced for the peripheral than the central visual field representation within area 17, particularly between the age of 2 and 4 months [Laskowska-Macios, Cereb Cortex, 2014]. In this study, we probed for related dynamic changes in the cortical proteome. We introduced age, cortical region and BD as principal variables in a 2-D DIGE screen of area 17. In this way we explored the potential of BD-related protein expression changes between central and peripheral area 17 of 2- and 4-month-old BD (2BD, 4BD) kittens as a valid parameter towards the identification of brain maturation-related molecular processes. Consistent with the maturation delay, distinct developmental protein expression changes observed for normal kittens were postponed by BD, especially in the peripheral region. These BD-induced proteomic changes suggest a negative regulation of neurite outgrowth, synaptic transmission and clathrin-mediated endocytosis, thereby implicating these processes in normal experience-induced visual cortex maturation. Verification of the expression of proteins from each of the biological processes via Western analysis disclosed that some of the transient proteomic changes correlate to the distinct behavioral outcome in adult life, depending on timing and duration of the BD period [Neuroscience 2013;255:99-109]. Taken together, the plasticity potential to recover from BD, in relation to ensuing restoration of normal visual input, appears to rely on specific protein expression changes and cellular processes induced by the loss of pattern vision in early life.

Optimal spatiotemporal representation of multichannel EEG for recognition of brain states associated with distinct visual stimulus

NASA Astrophysics Data System (ADS)

Hramov, Alexander; Musatov, Vyacheslav Yu.; Runnova, Anastasija E.; Efremova, Tatiana Yu.; Koronovskii, Alexey A.; Pisarchik, Alexander N.

2018-04-01

In the paper we propose an approach based on artificial neural networks for recognition of different human brain states associated with distinct visual stimulus. Based on the developed numerical technique and the analysis of obtained experimental multichannel EEG data, we optimize the spatiotemporal representation of multichannel EEG to provide close to 97% accuracy in recognition of the EEG brain states during visual perception. Different interpretations of an ambiguous image produce different oscillatory patterns in the human EEG with similar features for every interpretation. Since these features are inherent to all subjects, a single artificial network can classify with high quality the associated brain states of other subjects.

Interference Effects Demonstrate Distinct Roles for Visual and Motor Imagery during the Mental Representation of Human Action

ERIC Educational Resources Information Center

Stevens, J.A.

2005-01-01

Four experiments were completed to characterize the utilization of visual imagery and motor imagery during the mental representation of human action. In Experiment 1, movement time functions for a motor imagery human locomotion task conformed to a speed-accuracy trade-off similar to Fitts' Law, whereas those for a visual imagery object motion task…

Amodal Semantic Representations Depend on both Anterior Temporal Lobes: Evidence from Repetitive Transcranial Magnetic Stimulation

ERIC Educational Resources Information Center

Pobric, Gorana; Jefferies, Elizabeth; Ralph, Matthew A. Lambon

2010-01-01

The key question of how the brain codes the meaning of words and pictures is the focus of vigorous debate. Is there a "semantic hub" in the temporal poles where these different inputs converge to form amodal conceptual representations? Alternatively, are there distinct neural circuits that underpin our comprehension of pictures and words?…

One's own country and familiar places in the mind's eye: different topological representations for navigational and non-navigational contents.

PubMed

Boccia, M; Piccardi, L; Palermo, L; Nemmi, F; Sulpizio, V; Galati, G; Guariglia, C

2014-09-05

Visual mental imagery is a process that draws on different cognitive abilities and is affected by the contents of mental images. Several studies have demonstrated that different brain areas subtend the mental imagery of navigational and non-navigational contents. Here, we set out to determine whether there are distinct representations for navigational and geographical images. Specifically, we used a Spatial Compatibility Task (SCT) to assess the mental representation of a familiar navigational space (the campus), a familiar geographical space (the map of Italy) and familiar objects (the clock). Twenty-one participants judged whether the vertical or the horizontal arrangement of items was correct. We found that distinct representational strategies were preferred to solve different categories on the SCT, namely, the horizontal perspective for the campus and the vertical perspective for the clock and the map of Italy. Furthermore, we found significant effects due to individual differences in the vividness of mental images and in preferences for verbal versus visual strategies, which selectively affect the contents of mental images. Our results suggest that imagining a familiar navigational space is somewhat different from imagining a familiar geographical space. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Activity inference for Ambient Intelligence through handling artifacts in a healthcare environment.

PubMed

Martínez-Pérez, Francisco E; González-Fraga, Jose Ángel; Cuevas-Tello, Juan C; Rodríguez, Marcela D

2012-01-01

Human activity inference is not a simple process due to distinct ways of performing it. Our proposal presents the SCAN framework for activity inference. SCAN is divided into three modules: (1) artifact recognition, (2) activity inference, and (3) activity representation, integrating three important elements of Ambient Intelligence (AmI) (artifact-behavior modeling, event interpretation and context extraction). The framework extends the roaming beat (RB) concept by obtaining the representation using three kinds of technologies for activity inference. The RB is based on both analysis and recognition from artifact behavior for activity inference. A practical case is shown in a nursing home where a system affording 91.35% effectiveness was implemented in situ. Three examples are shown using RB representation for activity representation. Framework description, RB description and CALog system overcome distinct problems such as the feasibility to implement AmI systems, and to show the feasibility for accomplishing the challenges related to activity recognition based on artifact recognition. We discuss how the use of RBs might positively impact the problems faced by designers and developers for recovering information in an easier manner and thus they can develop tools focused on the user.

Activity Inference for Ambient Intelligence Through Handling Artifacts in a Healthcare Environment

PubMed Central

Martínez-Pérez, Francisco E.; González-Fraga, Jose Ángel; Cuevas-Tello, Juan C.; Rodríguez, Marcela D.

2012-01-01

Human activity inference is not a simple process due to distinct ways of performing it. Our proposal presents the SCAN framework for activity inference. SCAN is divided into three modules: (1) artifact recognition, (2) activity inference, and (3) activity representation, integrating three important elements of Ambient Intelligence (AmI) (artifact-behavior modeling, event interpretation and context extraction). The framework extends the roaming beat (RB) concept by obtaining the representation using three kinds of technologies for activity inference. The RB is based on both analysis and recognition from artifact behavior for activity inference. A practical case is shown in a nursing home where a system affording 91.35% effectiveness was implemented in situ. Three examples are shown using RB representation for activity representation. Framework description, RB description and CALog system overcome distinct problems such as the feasibility to implement AmI systems, and to show the feasibility for accomplishing the challenges related to activity recognition based on artifact recognition. We discuss how the use of RBs might positively impact the problems faced by designers and developers for recovering information in an easier manner and thus they can develop tools focused on the user. PMID:22368512

The Sensory Neurons of Touch

PubMed Central

Abraira, Victoria E.; Ginty, David D.

2013-01-01

The somatosensory system decodes a wide range of tactile stimuli and thus endows us with a remarkable capacity for object recognition, texture discrimination, sensory-motor feedback and social exchange. The first step leading to perception of innocuous touch is activation of cutaneous sensory neurons called low-threshold mechanoreceptors (LTMRs). Here, we review the properties and functions of LTMRs, emphasizing the unique tuning properties of LTMR subtypes and the organizational logic of their peripheral and central axonal projections. We discuss the spinal cord neurophysiological representation of complex mechanical forces acting upon the skin and current views of how tactile information is processed and conveyed from the spinal cord to the brain. An integrative model in which ensembles of impulses arising from physiologically distinct LTMRs are integrated and processed in somatotopically aligned mechanosensory columns of the spinal cord dorsal horn underlies the nervous system’s enormous capacity for perceiving the richness of the tactile world. PMID:23972592

An Ontology-based Architecture for Integration of Clinical Trials Management Applications

PubMed Central

Shankar, Ravi D.; Martins, Susana B.; O’Connor, Martin; Parrish, David B.; Das, Amar K.

2007-01-01

Management of complex clinical trials involves coordinated-use of a myriad of software applications by trial personnel. The applications typically use distinct knowledge representations and generate enormous amount of information during the course of a trial. It becomes vital that the applications exchange trial semantics in order for efficient management of the trials and subsequent analysis of clinical trial data. Existing model-based frameworks do not address the requirements of semantic integration of heterogeneous applications. We have built an ontology-based architecture to support interoperation of clinical trial software applications. Central to our approach is a suite of clinical trial ontologies, which we call Epoch, that define the vocabulary and semantics necessary to represent information on clinical trials. We are continuing to demonstrate and validate our approach with different clinical trials management applications and with growing number of clinical trials. PMID:18693919

Visual search, visual streams, and visual architectures.

PubMed

Green, M

1991-10-01

Most psychological, physiological, and computational models of early vision suggest that retinal information is divided into a parallel set of feature modules. The dominant theories of visual search assume that these modules form a "blackboard" architecture: a set of independent representations that communicate only through a central processor. A review of research shows that blackboard-based theories, such as feature-integration theory, cannot easily explain the existing data. The experimental evidence is more consistent with a "network" architecture, which stresses that: (1) feature modules are directly connected to one another, (2) features and their locations are represented together, (3) feature detection and integration are not distinct processing stages, and (4) no executive control process, such as focal attention, is needed to integrate features. Attention is not a spotlight that synthesizes objects from raw features. Instead, it is better to conceptualize attention as an aperture which masks irrelevant visual information.

Learning to File: Reconfiguring Information and Information Work in the Early Twentieth Century.

PubMed

Robertson, Craig

2017-01-01

This article uses textbooks and advertisements to explore the formal and informal ways in which people were introduced to vertical filing in the early twentieth century. Through the privileging of "system" an ideal mode of paperwork emerged in which a clerk could "grasp" information simply by hand without having to understand or comprehend its content. A file clerk's hands and fingers became central to the representation and teaching of filing. In this way, filing offered an example of a distinctly modern form of information work. Filing textbooks sought to enhance dexterity as the rapid handling of paper came to represent information as something that existed in discrete units, in bits that could be easily extracted. Advertisements represented this mode of information work in its ideal form when they frequently erased the worker or reduced him or her to hands, as "instant" filing became "automatic" filing, with the filing cabinet presented as a machine.

Neuroanatomic organization of sound memory in humans.

PubMed

Kraut, Michael A; Pitcock, Jeffery A; Calhoun, Vince; Li, Juan; Freeman, Thomas; Hart, John

2006-11-01

The neural interface between sensory perception and memory is a central issue in neuroscience, particularly initial memory organization following perceptual analyses. We used functional magnetic resonance imaging to identify anatomic regions extracting initial auditory semantic memory information related to environmental sounds. Two distinct anatomic foci were detected in the right superior temporal gyrus when subjects identified sounds representing either animals or threatening items. Threatening animal stimuli elicited signal changes in both foci, suggesting a distributed neural representation. Our results demonstrate both category- and feature-specific responses to nonverbal sounds in early stages of extracting semantic memory information from these sounds. This organization allows for these category-feature detection nodes to extract early, semantic memory information for efficient processing of transient sound stimuli. Neural regions selective for threatening sounds are similar to those of nonhuman primates, demonstrating semantic memory organization for basic biological/survival primitives are present across species.

The Inevitability and Importance of Genres in Narrative Research on Teaching Practice

ERIC Educational Resources Information Center

Rosiek, Jerry; Atkinson, Becky

2007-01-01

The authors examine the field of contemporary teacher knowledge research. Specifically, they examine the use of narrative representations by researchers in this field. They make a general argument for the development of distinct narrative genres in teacher knowledge research because considerations of distinct genre styles can help researchers…

Deep Levels of Processing Elicit a Distinctiveness Heuristic: Evidence from the Criterial Recollection Task

ERIC Educational Resources Information Center

Gallo, David A.; Meadow, Nathaniel G.; Johnson, Elizabeth L.; Foster, Katherine T.

2008-01-01

Thinking about the meaning of studied words (deep processing) enhances memory on typical recognition tests, relative to focusing on perceptual features (shallow processing). One explanation for this levels-of-processing effect is that deep processing leads to the encoding of more distinctive representations (i.e., more unique semantic or…

Evidence for sparse synergies in grasping actions.

PubMed

Prevete, Roberto; Donnarumma, Francesco; d'Avella, Andrea; Pezzulo, Giovanni

2018-01-12

Converging evidence shows that hand-actions are controlled at the level of synergies and not single muscles. One intriguing aspect of synergy-based action-representation is that it may be intrinsically sparse and the same synergies can be shared across several distinct types of hand-actions. Here, adopting a normative angle, we consider three hypotheses for hand-action optimal-control: sparse-combination hypothesis (SC) - sparsity in the mapping between synergies and actions - i.e., actions implemented using a sparse combination of synergies; sparse-elements hypothesis (SE) - sparsity in synergy representation - i.e., the mapping between degrees-of-freedom (DoF) and synergies is sparse; double-sparsity hypothesis (DS) - a novel view combining both SC and SE - i.e., both the mapping between DoF and synergies and between synergies and actions are sparse, each action implementing a sparse combination of synergies (as in SC), each using a limited set of DoFs (as in SE). We evaluate these hypotheses using hand kinematic data from six human subjects performing nine different types of reach-to-grasp actions. Our results support DS, suggesting that the best action representation is based on a relatively large set of synergies, each involving a reduced number of degrees-of-freedom, and that distinct sets of synergies may be involved in distinct tasks.

Distinct Gamma-Band Components Reflect the Short-Term Memory Maintenance of Different Sound Lateralization Angles

PubMed Central

Heidegger, Tonio; Wibral, Michael; Altmann, Christian F.; Lutzenberger, Werner

2008-01-01

Oscillatory activity in human electro- or magnetoencephalogram has been related to cortical stimulus representations and their modulation by cognitive processes. Whereas previous work has focused on gamma-band activity (GBA) during attention or maintenance of representations, there is little evidence for GBA reflecting individual stimulus representations. The present study aimed at identifying stimulus-specific GBA components during auditory spatial short-term memory. A total of 28 adults were assigned to 1 of 2 groups who were presented with only right- or left-lateralized sounds, respectively. In each group, 2 sample stimuli were used which differed in their lateralization angles (15° or 45°) with respect to the midsagittal plane. Statistical probability mapping served to identify spectral amplitude differences between 15° versus 45° stimuli. Distinct GBA components were found for each sample stimulus in different sensors over parieto-occipital cortex contralateral to the side of stimulation peaking during the middle 200–300 ms of the delay phase. The differentiation between “preferred” and “nonpreferred” stimuli during the final 100 ms of the delay phase correlated with task performance. These findings suggest that the observed GBA components reflect the activity of distinct networks tuned to spatial sound features which contribute to the maintenance of task-relevant information in short-term memory. PMID:18252742

Neglecting the Left Side of a City Square but Not the Left Side of Its Clock: Prevalence and Characteristics of Representational Neglect

PubMed Central

Guariglia, Cecilia; Palermo, Liana; Piccardi, Laura; Iaria, Giuseppe; Incoccia, Chiara

2013-01-01

Representational neglect, which is characterized by the failure to report left-sided details of a mental image from memory, can occur after a right hemisphere lesion. In this study, we set out to verify the hypothesis that two distinct forms of representational neglect exist, one involving object representation and the other environmental representation. As representational neglect is considered rare, we also evaluated the prevalence and frequency of its association with perceptual neglect. We submitted a group of 96 unselected, consecutive, chronic, right brain-damaged patients to an extensive neuropsychological evaluation that included two representational neglect tests: the Familiar Square Description Test and the O'Clock Test. Representational neglect, as well as perceptual neglect, was present in about one-third of the sample. Most patients neglected the left side of imagined familiar squares but not the left side of imagined clocks. The present data show that representational neglect is not a rare disorder and also support the hypothesis that two different types of mental representations (i.e. topological and non-topological images) may be selectively damaged in representational neglect. PMID:23874416

Model Package Report: Central Plateau Vadose Zone Geoframework Version 1.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, Sarah D.

The purpose of the Central Plateau Vadose Zone (CPVZ) Geoframework model (GFM) is to provide a reasonable, consistent, and defensible three-dimensional (3D) representation of the vadose zone beneath the Central Plateau at the Hanford Site to support the Composite Analysis (CA) vadose zone contaminant fate and transport models. The GFM is a 3D representation of the subsurface geologic structure. From this 3D geologic model, exported results in the form of point, surface, and/or volumes are used as inputs to populate and assemble the various numerical model architectures, providing a 3D-layered grid that is consistent with the GFM. The objective ofmore » this report is to define the process used to produce a hydrostratigraphic model for the vadose zone beneath the Hanford Site Central Plateau and the corresponding CA domain.« less

DNA → RNA: What Do Students Think the Arrow Means?

PubMed

Wright, L Kate; Fisk, J Nick; Newman, Dina L

2014-01-01

The central dogma of molecular biology, a model that has remained intact for decades, describes the transfer of genetic information from DNA to protein though an RNA intermediate. While recent work has illustrated many exceptions to the central dogma, it is still a common model used to describe and study the relationship between genes and protein products. We investigated understanding of central dogma concepts and found that students are not primed to think about information when presented with the canonical figure of the central dogma. We also uncovered conceptual errors in student interpretation of the meaning of the transcription arrow in the central dogma representation; 36% of students (n = 128; all undergraduate levels) described transcription as a chemical conversion of DNA into RNA or suggested that RNA existed before the process of transcription began. Interviews confirm that students with weak conceptual understanding of information flow find inappropriate meaning in the canonical representation of central dogma. Therefore, we suggest that use of this representation during instruction can be counterproductive unless educators are explicit about the underlying meaning. © 2014 L. K. Wright et al. CBE—Life Sciences Education © 2014 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Reconstructing dynamic mental models of facial expressions in prosopagnosia reveals distinct representations for identity and expression.

PubMed

Richoz, Anne-Raphaëlle; Jack, Rachael E; Garrod, Oliver G B; Schyns, Philippe G; Caldara, Roberto

2015-04-01

The human face transmits a wealth of signals that readily provide crucial information for social interactions, such as facial identity and emotional expression. Yet, a fundamental question remains unresolved: does the face information for identity and emotional expression categorization tap into common or distinct representational systems? To address this question we tested PS, a pure case of acquired prosopagnosia with bilateral occipitotemporal lesions anatomically sparing the regions that are assumed to contribute to facial expression (de)coding (i.e., the amygdala, the insula and the posterior superior temporal sulcus--pSTS). We previously demonstrated that PS does not use information from the eye region to identify faces, but relies on the suboptimal mouth region. PS's abnormal information use for identity, coupled with her neural dissociation, provides a unique opportunity to probe the existence of a dichotomy in the face representational system. To reconstruct the mental models of the six basic facial expressions of emotion in PS and age-matched healthy observers, we used a novel reverse correlation technique tracking information use on dynamic faces. PS was comparable to controls, using all facial features to (de)code facial expressions with the exception of fear. PS's normal (de)coding of dynamic facial expressions suggests that the face system relies either on distinct representational systems for identity and expression, or dissociable cortical pathways to access them. Interestingly, PS showed a selective impairment for categorizing many static facial expressions, which could be accounted for by her lesion in the right inferior occipital gyrus. PS's advantage for dynamic facial expressions might instead relate to a functionally distinct and sufficient cortical pathway directly connecting the early visual cortex to the spared pSTS. Altogether, our data provide critical insights on the healthy and impaired face systems, question evidence of deficits obtained from patients by using static images of facial expressions, and offer novel routes for patient rehabilitation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exploring Middle School Students' Representational Competence in Science: Development and Verification of a Framework for Learning with Visual Representations

NASA Astrophysics Data System (ADS)

Tippett, Christine Diane

Scientific knowledge is constructed and communicated through a range of forms in addition to verbal language. Maps, graphs, charts, diagrams, formulae, models, and drawings are just some of the ways in which science concepts can be represented. Representational competence---an aspect of visual literacy that focuses on the ability to interpret, transform, and produce visual representations---is a key component of science literacy and an essential part of science reading and writing. To date, however, most research has examined learning from representations rather than learning with representations. This dissertation consisted of three distinct projects that were related by a common focus on learning from visual representations as an important aspect of scientific literacy. The first project was the development of an exploratory framework that is proposed for use in investigations of students constructing and interpreting multimedia texts. The exploratory framework, which integrates cognition, metacognition, semiotics, and systemic functional linguistics, could eventually result in a model that might be used to guide classroom practice, leading to improved visual literacy, better comprehension of science concepts, and enhanced science literacy because it emphasizes distinct aspects of learning with representations that can be addressed though explicit instruction. The second project was a metasynthesis of the research that was previously conducted as part of the Explicit Literacy Instruction Embedded in Middle School Science project (Pacific CRYSTAL, http://www.educ.uvic.ca/pacificcrystal). Five overarching themes emerged from this case-to-case synthesis: the engaging and effective nature of multimedia genres, opportunities for differentiated instruction using multimodal strategies, opportunities for assessment, an emphasis on visual representations, and the robustness of some multimodal literacy strategies across content areas. The third project was a mixed-methods verification study that was conducted to refine and validate the theoretical framework. This study examined middle school students' representational competence and focused on students' creation of visual representations such as labelled diagrams, a form of representation commonly found in science information texts and textbooks. An analysis of the 31 Grade 6 participants' representations and semistructured interviews revealed five themes, each of which supports one or more dimensions of the exploratory framework: participants' use of color, participants' choice of representation (form and function), participants' method of planning for representing, participants' knowledge of conventions, and participants' selection of information to represent. Together, the results of these three projects highlight the need for further research on learning with rather than learning from representations.

A Qualitative Report of the Ways High School Chemistry Students Attempt to Represent a Chemical Reaction at the Atomic/Molecular Level

ERIC Educational Resources Information Center

Kern, Anne L.; Wood, Nathan B.; Roehrig, Gillian H.; Nyachwaya, James

2010-01-01

We report the findings of a large-scale (n = 1,337) qualitative descriptive analysis of U.S. high schools students' particulate representations of a chemical reaction, specifically, the combustion of methane. Data were collected as part of an end of course exam. Student representations were coded into 17 distinct subcategories under one of five…

Representation of grasp postures and anticipatory motor planning in children.

PubMed

Stöckel, Tino; Hughes, Charmayne M L; Schack, Thomas

2012-11-01

In this study, we investigated anticipatory motor planning and the development of cognitive representation of grasp postures in children aged 7, 8, and 9 years. Overall, 9-year-old children were more likely to plan their movements to end in comfortable postures, and have distinct representational structures of certain grasp postures, compared to the 7- and 8-year old children. Additionally, the sensitivity toward comfortable end-states (end-state comfort) was related to the mental representation of certain grasp postures. Children with grasp comfort related and functionally well-structured representations were more likely to have satisfied end-state comfort in both the simple and the advanced planning condition. In contrast, end-state comfort satisfaction for the advanced planning condition was much lower for children whose cognitive representations were not structured by grasp comfort. The results of the present study support the notion that cognitive action representation plays an important role in the planning and control of grasp postures.

Central tendency effects in time interval reproduction in autism

PubMed Central

Karaminis, Themelis; Cicchini, Guido Marco; Neil, Louise; Cappagli, Giulia; Aagten-Murphy, David; Burr, David; Pellicano, Elizabeth

2016-01-01

Central tendency, the tendency of judgements of quantities (lengths, durations etc.) to gravitate towards their mean, is one of the most robust perceptual effects. A Bayesian account has recently suggested that central tendency reflects the integration of noisy sensory estimates with prior knowledge representations of a mean stimulus, serving to improve performance. The process is flexible, so prior knowledge is weighted more heavily when sensory estimates are imprecise, requiring more integration to reduce noise. In this study we measure central tendency in autism to evaluate a recent theoretical hypothesis suggesting that autistic perception relies less on prior knowledge representations than typical perception. If true, autistic children should show reduced central tendency than theoretically predicted from their temporal resolution. We tested autistic and age- and ability-matched typical children in two child-friendly tasks: (1) a time interval reproduction task, measuring central tendency in the temporal domain; and (2) a time discrimination task, assessing temporal resolution. Central tendency reduced with age in typical development, while temporal resolution improved. Autistic children performed far worse in temporal discrimination than the matched controls. Computational simulations suggested that central tendency was much less in autistic children than predicted by theoretical modelling, given their poor temporal resolution. PMID:27349722

Mathematical formalisms based on approximated kinetic representations for modeling genetic and metabolic pathways.

PubMed

Alves, Rui; Vilaprinyo, Ester; Hernádez-Bermejo, Benito; Sorribas, Albert

2008-01-01

There is a renewed interest in obtaining a systemic understanding of metabolism, gene expression and signal transduction processes, driven by the recent research focus on Systems Biology. From a biotechnological point of view, such a systemic understanding of how a biological system is designed to work can facilitate the rational manipulation of specific pathways in different cell types to achieve specific goals. Due to the intrinsic complexity of biological systems, mathematical models are a central tool for understanding and predicting the integrative behavior of those systems. Particularly, models are essential for a rational development of biotechnological applications and in understanding system's design from an evolutionary point of view. Mathematical models can be obtained using many different strategies. In each case, their utility will depend upon the properties of the mathematical representation and on the possibility of obtaining meaningful parameters from available data. In practice, there are several issues at stake when one has to decide which mathematical model is more appropriate for the study of a given problem. First, one needs a model that can represent the aspects of the system one wishes to study. Second, one must choose a mathematical representation that allows an accurate analysis of the system with respect to different aspects of interest (for example, robustness of the system, dynamical behavior, optimization of the system with respect to some production goal, parameter value determination, etc). Third, before choosing between alternative and equally appropriate mathematical representations for the system, one should compare representations with respect to easiness of automation for model set-up, simulation, and analysis of results. Fourth, one should also consider how to facilitate model transference and re-usability by other researchers and for distinct purposes. Finally, one factor that is important for all four aspects is the regularity in the mathematical structure of the equations because it facilitates computational manipulation. This regularity is a mark of kinetic representations based on approximation theory. The use of approximation theory to derive mathematical representations with regular structure for modeling purposes has a long tradition in science. In most applied fields, such as engineering and physics, those approximations are often required to obtain practical solutions to complex problems. In this paper we review some of the more popular mathematical representations that have been derived using approximation theory and are used for modeling in molecular systems biology. We will focus on formalisms that are theoretically supported by the Taylor Theorem. These include the Power-law formalism, the recently proposed (log)linear and Lin-log formalisms as well as some closely related alternatives. We will analyze the similarities and differences between these formalisms, discuss the advantages and limitations of each representation, and provide a tentative "road map" for their potential utilization for different problems.

Spatio-temporal dynamics of processing non-symbolic number: An ERP source localization study

PubMed Central

Hyde, Daniel C.; Spelke, Elizabeth S.

2013-01-01

Coordinated studies with adults, infants, and nonhuman animals provide evidence for two distinct systems of non-verbal number representation. The ‘parallel individuation’ system selects and retains information about 1–3 individual entities and the ‘numerical magnitude’ system establishes representations of the approximate cardinal value of a group. Recent ERP work has demonstrated that these systems reliably evoke functionally and temporally distinct patterns of brain response that correspond to established behavioral signatures. However, relatively little is known about the neural generators of these ERP signatures. To address this question, we targeted known ERP signatures of these systems, by contrasting processing of small versus large non-symbolic numbers, and used a source localization algorithm (LORETA) to identify their cortical origins. Early processing of small numbers, showing the signature effects of parallel individuation on the N1 (∼150 ms), was localized primarily to extrastriate visual regions. In contrast, qualitatively and temporally distinct processing of large numbers, showing the signatures of approximate number representation on the mid-latency P2p (∼200–250 ms), was localized primarily to right intraparietal regions. In comparison, mid-latency small number processing was localized to the right temporal-parietal junction and left-lateralized intraparietal regions. These results add spatial information to the emerging ERP literature documenting the process by which we represent number. Furthermore, these results substantiate recent claims that early attentional processes determine whether a collection of objects will be represented through parallel individuation or as an approximate numerical magnitude by providing evidence that downstream processing diverges to distinct cortical regions. PMID:21830257

Spatiotemporal dynamics of processing nonsymbolic number: an event-related potential source localization study.

PubMed

Hyde, Daniel C; Spelke, Elizabeth S

2012-09-01

Coordinated studies with adults, infants, and nonhuman animals provide evidence for two distinct systems of nonverbal number representation. The "parallel individuation" (PI) system selects and retains information about one to three individual entities and the "numerical magnitude" system establishes representations of the approximate cardinal value of a group. Recent event-related potential (ERP) work has demonstrated that these systems reliably evoke functionally and temporally distinct patterns of brain response that correspond to established behavioral signatures. However, relatively little is known about the neural generators of these ERP signatures. To address this question, we targeted known ERP signatures of these systems, by contrasting processing of small versus large nonsymbolic numbers, and used a source localization algorithm (LORETA) to identify their cortical origins. Early processing of small numbers, showing the signature effects of PI on the N1 (∼150 ms), was localized primarily to extrastriate visual regions. In contrast, qualitatively and temporally distinct processing of large numbers, showing the signatures of approximate number representation on the mid-latency P2p (∼200-250 ms), was localized primarily to right intraparietal regions. In comparison, mid-latency small number processing was localized to the right temporal-parietal junction and left-lateralized intraparietal regions. These results add spatial information to the emerging ERP literature documenting the process by which we represent number. Furthermore, these results substantiate recent claims that early attentional processes determine whether a collection of objects will be represented through PI or as an approximate numerical magnitude by providing evidence that downstream processing diverges to distinct cortical regions. Copyright © 2011 Wiley Periodicals, Inc.

Modeling and characterization of the CEJ for optimization of esthetic implant design.

PubMed

Gallucci, German O; Belser, Urs C; Bernard, Jean-Pierre; Magne, Pascal

2004-02-01

This study evaluated the dimensions and characteristics of the cementoenamel junction (CEJ) of maxillary anterior teeth; the natural CEJ was compared to current implant design and used for design optimization. Standardized digital images of 137 extracted human teeth (45 central incisors, 46 lateral incisors, and 46 canines) were used to measure cervical dimensions, CEJ curvature, and distance from zenith of CEJ to interdental contact on proximal views. The x- and y-coordinates of the CEJ contour were digitized before mathematic processing to allow the representation of a single average curve for buccal, palatal, mesial, and distal surfaces for each tooth type. These measurements were combined to existing data related to dentogingival and "implantomucosal" junction to extrapolate specific biologic landmarks around teeth and implants. Mean cervical dimensions, distance from zenith of CEJ to interdental contact, and CEJ curvature were compared. Cervical dimensions significantly differed, with a more symmetric cervical cross-section for central incisors, slightly more rectangular shape for lateral incisors, and distinctly rectangular shape for canines. CEJ curvature was statistically different between all tooth groups (centrals > laterals > canines); within groups, curvature value was always superior at the mesial aspect compared to distally (3.46 mm vs 3.13 mm for centrals, 2.97 mm vs 2.38 mm for laterals, and 2.55 mm vs 1.60 mm for canines). Tooth-implant biologic width discrepancies ranged from 4.10 to 5.96 mm and were different between all groups of teeth (centrals > laterals > canines); within groups, the discrepancy was always superior at the mesial aspect compared to distally. Current implant design featuring a flat, rotation-symmetric shoulder should be reconsidered in view of natural CEJ contour to improve biologic considerations and related esthetics.

Interactions between visual working memory representations.

PubMed

Bae, Gi-Yeul; Luck, Steven J

2017-11-01

We investigated whether the representations of different objects are maintained independently in working memory or interact with each other. Observers were shown two sequentially presented orientations and required to reproduce each orientation after a delay. The sequential presentation minimized perceptual interactions so that we could isolate interactions between memory representations per se. We found that similar orientations were repelled from each other whereas dissimilar orientations were attracted to each other. In addition, when one of the items was given greater attentional priority by means of a cue, the representation of the high-priority item was not influenced very much by the orientation of the low-priority item, but the representation of the low-priority item was strongly influenced by the orientation of the high-priority item. This indicates that attention modulates the interactions between working memory representations. In addition, errors in the reported orientations of the two objects were positively correlated under some conditions, suggesting that representations of distinct objects may become grouped together in memory. Together, these results demonstrate that working-memory representations are not independent but instead interact with each other in a manner that depends on attentional priority.

OBJECT REPRESENTATION, IDENTITY, AND THE PARADOX OF EARLY PERMANENCE: Steps Toward a New Framework.

PubMed

Meltzoff, Andrew N; Moore, M Keith

1998-01-01

The sensorimotor theory of infancy has been overthrown, but there is little consensus on a replacement. We hypothesize that a capacity for representation is the starting point for infant development, not its culmination. Logical distinctions are drawn between object representation, identity, and permanence. Modern experiments on early object permanence and deferred imitation suggest: (a) even for young infants, representations persist over breaks in sensory contact, (b) numerical identity of objects ( O s) is initially specified by spatiotemporal criteria (place and trajectory), (c) featural and functional identity criteria develop, (d) events are analyzed by comparing representations to current perception, and (e) representation operates both prospectively, anticipating future contacts with an O , and retrospectively, reidentifying an O as the "same one again." A model of the architecture and functioning of the early representational system is proposed. It accounts for young infants' behavior toward absent people and things in terms of their efforts to determine the identity of objects. Our proposal is developmental without denying innate structure and elevates the power of perception and representation while being cautious about attributing complex concepts to young infants.

OBJECT REPRESENTATION, IDENTITY, AND THE PARADOX OF EARLY PERMANENCE: Steps Toward a New Framework

PubMed Central

Meltzoff, Andrew N.; Moore, M. Keith

2013-01-01

The sensorimotor theory of infancy has been overthrown, but there is little consensus on a replacement. We hypothesize that a capacity for representation is the starting point for infant development, not its culmination. Logical distinctions are drawn between object representation, identity, and permanence. Modern experiments on early object permanence and deferred imitation suggest: (a) even for young infants, representations persist over breaks in sensory contact, (b) numerical identity of objects (Os) is initially specified by spatiotemporal criteria (place and trajectory), (c) featural and functional identity criteria develop, (d) events are analyzed by comparing representations to current perception, and (e) representation operates both prospectively, anticipating future contacts with an O, and retrospectively, reidentifying an O as the “same one again.” A model of the architecture and functioning of the early representational system is proposed. It accounts for young infants’ behavior toward absent people and things in terms of their efforts to determine the identity of objects. Our proposal is developmental without denying innate structure and elevates the power of perception and representation while being cautious about attributing complex concepts to young infants. PMID:25147418

The Attachment Doll Play Assessment: Predictive Validity with Concurrent Mother-Child Interaction and Maternal Caregiving Representations

PubMed Central

George, Carol; Solomon, Judith

2016-01-01

Attachment is central to the development of children’s regulatory processes. It has been associated with developmental and psychiatric health across the life span, especially emotional and behavioral regulation of negative affect when stressed (Schore, 2001; Schore and Schore, 2008). Assessment of attachment patterns provides a critical frame for understanding emerging developmental competencies and formulating treatment and intervention. Play-based attachment assessments provide access to representational models of attachment, which are regarded in attachment theory as the central organizing mechanisms associated with stability or change (Bowlby, 1969/1982; Bretherton and Munholland, 2008). The Attachment Doll Play Assessment (ADPA, George and Solomon, 1990–2016; Solomon et al., 1995) is a prominent established representational attachment measure for children aged early latency through childhood. This study examines the predictive validity of the ADPA to caregiving accessibility and responsiveness assessed from mother-child interaction and maternal representation. Sixty nine mothers and their 5–7-year-old children participated in this study. Mother-child interaction was observed during a pre-separation dyadic interaction task. Caregiving representations were rated from the Caregiving Interview (George and Solomon, 1988/1993/2005/2007). Child security with mother was associated with positive dyadic interaction and flexibly integrated maternal caregiving representations. Child controlling/disorganized attachments were significantly associated with problematic dyadic interaction and dysregulated-helpless maternal caregiving representations. The clinical implications and the use of the ADPA in clinical and educational settings are discussed. PMID:27803683

The Attachment Doll Play Assessment: Predictive Validity with Concurrent Mother-Child Interaction and Maternal Caregiving Representations.

PubMed

George, Carol; Solomon, Judith

2016-01-01

Attachment is central to the development of children's regulatory processes. It has been associated with developmental and psychiatric health across the life span, especially emotional and behavioral regulation of negative affect when stressed (Schore, 2001; Schore and Schore, 2008). Assessment of attachment patterns provides a critical frame for understanding emerging developmental competencies and formulating treatment and intervention. Play-based attachment assessments provide access to representational models of attachment, which are regarded in attachment theory as the central organizing mechanisms associated with stability or change (Bowlby, 1969/1982; Bretherton and Munholland, 2008). The Attachment Doll Play Assessment (ADPA, George and Solomon, 1990-2016; Solomon et al., 1995) is a prominent established representational attachment measure for children aged early latency through childhood. This study examines the predictive validity of the ADPA to caregiving accessibility and responsiveness assessed from mother-child interaction and maternal representation. Sixty nine mothers and their 5-7-year-old children participated in this study. Mother-child interaction was observed during a pre-separation dyadic interaction task. Caregiving representations were rated from the Caregiving Interview (George and Solomon, 1988/1993/2005/2007). Child security with mother was associated with positive dyadic interaction and flexibly integrated maternal caregiving representations. Child controlling/disorganized attachments were significantly associated with problematic dyadic interaction and dysregulated-helpless maternal caregiving representations. The clinical implications and the use of the ADPA in clinical and educational settings are discussed.

Representational Competence: Towards a Distributed and Embodied Cognition Account

ERIC Educational Resources Information Center

Pande, Prajakt; Chandrasekharan, Sanjay

2017-01-01

Multiple external representations (MERs) are central to the practice and learning of science, mathematics and engineering, as the phenomena and entities investigated and controlled in these domains are often not available for perception and action. MERs therefore play a twofold constitutive role in reasoning in these domains. Firstly, MERs stand…

Large-Scale Modeling of Wordform Learning and Representation

ERIC Educational Resources Information Center

Sibley, Daragh E.; Kello, Christopher T.; Plaut, David C.; Elman, Jeffrey L.

2008-01-01

The forms of words as they appear in text and speech are central to theories and models of lexical processing. Nonetheless, current methods for simulating their learning and representation fail to approach the scale and heterogeneity of real wordform lexicons. A connectionist architecture termed the "sequence encoder" is used to learn…

Encoding, Memory, and Transcoding Deficits in Childhood Apraxia of Speech

ERIC Educational Resources Information Center

Shriberg, Lawrence D.; Lohmeier, Heather L.; Strand, Edythe A.; Jakielski, Kathy J.

2012-01-01

A central question in Childhood Apraxia of Speech (CAS) is whether the core phenotype is limited to transcoding (planning/programming) deficits or if speakers with CAS also have deficits in auditory-perceptual "encoding" (representational) and/or "memory" (storage and retrieval of representations) processes. We addressed this and other questions…

Geography and the Decennial Task of Redistricting.

ERIC Educational Resources Information Center

Webster, Gerald R.

1997-01-01

Examines the geographical and political forces that are central to the process of legislative redistricting. Reviews the historical background of the redistricting process and discusses the importance of minority representation. Briefly looks at some of the alternative systems of representation that have been suggested to improve the quality of…

Uncertainty Representation and Interpretation in Model-Based Prognostics Algorithms Based on Kalman Filter Estimation

NASA Technical Reports Server (NTRS)

Galvan, Jose Ramon; Saxena, Abhinav; Goebel, Kai Frank

2012-01-01

This article discusses several aspects of uncertainty representation and management for model-based prognostics methodologies based on our experience with Kalman Filters when applied to prognostics for electronics components. In particular, it explores the implications of modeling remaining useful life prediction as a stochastic process, and how it relates to uncertainty representation, management and the role of prognostics in decision-making. A distinction between the interpretations of estimated remaining useful life probability density function is explained and a cautionary argument is provided against mixing interpretations for two while considering prognostics in making critical decisions.

Temporal Stability and Authenticity of Self-Representations in Adulthood

PubMed Central

Diehl, Manfred; Jacobs, Laurie M.; Hastings, Catherine T.

2008-01-01

The temporal stability of role-specific self-representations was examined in a sample of 188 young, middle-aged, and older adults. Considerable stability was observed for all self-representations. Central self-descriptors showed significantly greater temporal stability than peripheral self-descriptors. Temporal stability of self-representations was positively associated with self-concept clarity, self-esteem, and positive affect (PA). Age differences were obtained for three of the five self-representations, with older adults showing significantly lower stabilities for self with family, self with friend, and self with significant other compared to young and middle-aged adults. Assessment of the authenticity of adults’ role-specific self-representations showed that greater authenticity tended to be associated with greater temporal stability. Authenticity and the number of positive daily events were significant positive predictors of the stability of self-representations. PMID:18820732

Reading Comprehension in Children with ADHD: Cognitive Underpinnings of the Centrality Deficit

PubMed Central

Miller, Amanda C.; Keenan, Janice M.; Betjemann, Rebecca S.; Willcutt, Erik; Pennington, Bruce F.; Olson, Richard K.

2012-01-01

We examined reading comprehension in children with ADHD by assessing their ability to build a coherent mental representation that allows them to recall central and peripheral information. We compared children with ADHD (mean age 9.78) to word reading-matched controls (mean age 9.89) on their ability to retell a passage. We found that even though children with ADHD recalled more central than peripheral information, they showed their greatest deficit, relative to controls, on central information – a centrality deficit (Miller & Keenan, 2009). We explored the cognitive underpinnings of this deficit using regressions to compare how well cognitive factors (working memory, inhibition, processing speed, and IQ) predicted the ability to recall central information, after controlling for word reading ability, and whether these cognitive factors interacted with ADHD symptoms. Working memory accounted for the most unique variance. Although previous evidence for reading comprehension difficulties in children with ADHD have been mixed, this study suggests that even when word reading ability is controlled, children with ADHD have difficulty building a coherent mental representation, and this difficulty is likely related to deficits in working memory. PMID:23054132

Neural representations of social status hierarchy in human inferior parietal cortex.

PubMed

Chiao, Joan Y; Harada, Tokiko; Oby, Emily R; Li, Zhang; Parrish, Todd; Bridge, Donna J

2009-01-01

Mental representations of social status hierarchy share properties with that of numbers. Previous neuroimaging studies have shown that the neural representation of numerical magnitude lies within a network of regions within inferior parietal cortex. However the neural basis of social status hierarchy remains unknown. Using fMRI, we studied subjects while they compared social status magnitude of people, objects and symbols, as well as numerical magnitude. Both social status and number comparisons recruited bilateral intraparietal sulci. We also observed a semantic distance effect whereby neural activity within bilateral intraparietal sulci increased for semantically close relative to far numerical and social status comparisons. These results demonstrate that social status and number comparisons recruit distinct and overlapping neuronal representations within human inferior parietal cortex.

Representation and transformation of Langley's map of the infrared solar spectrum

NASA Astrophysics Data System (ADS)

Loettgers, Andrea

In 1900, after 18 years of research, the American astrophysicist Samuel Pierpont Langley published the final report of his investigations in the infrared region of the solar spectrum. (See Samuel P. Langley: Annals of the Astrophysical Observatory of the Smithsonian Institution, Vol. 1, Washington: Goverment Printing Office, 1900.) In this report one finds three different types of maps of the infrared region, extending from 1.1 mu-m to 5.3 mu-m and showing the positions of 750 absorption lines: a bolograph, a line spectrum and a normal spectrum. (The bolograph, the line spectrum and the normal spectrum are accessible as pl. XX and XXIV at http://adsbit.harvard.edu/books/saoann/.) Looking at these three distinct forms of representation raises the questions: Why did Langley decide to use three representations for the visualization of his results? How are these distinct representations connected? An analysis of the first question will provide further insight into the ``connection between instruments, practices, and the visual'', into the recording, evaluation and processing of the data and, furthermore, into the historical and disciplinary contexts. The prevailing trend toward the automation of measuring and registration processes, and the associated claim of `mechanical objectivity', together with standards concerning precision and completeness set by Henry Rowland's photographic measurements in the visible part of the spectrum, turn out to be the strongest elements in the development of the different forms of representation and their respective transformations.

Lateral masking in cycling displays: the relative importance of separation, flanker duration, and interstimulus interval for object-mediated updating.

PubMed

Hein, Elisabeth; Moore, Cathleen M

2010-01-01

A central bar repeatedly presented in alternation with two flanking bars can lead to the disappearance of the central bar. Recently it has been suggested that this masking effect could be explained by object-mediated updating: the information from the central bar is integrated into the representation of the flankers, leading not only to the disappearance of the central bar as a separate object, but also to the perception of the flankers in apparent motion between their real position and the position of the central bar. This account suggests that the visibility of the central bar should depend on the same factors as those that influence the construction and maintenance of object representations. Therefore separation between central bar and flankers should not influence visibility as long as the time interval between them is adequate to make an interpretation of the scene in terms of one object moving from one location to the other possible location. We found that if the time interval between the central bar and the flankers is neither too short nor too long, the central bar becomes invisible even at large separations. These findings are inconsistent with traditional accounts of the cycling lateral masking displays in terms of local inhibitory mechanisms.

The Development of Reasoning about Beliefs: Fact, Preference, and Ideology.

PubMed

Heiphetz, Larisa; Spelke, Elizabeth S; Harris, Paul L; Banaji, Mahzarin R

2013-05-01

The beliefs people hold about the social and physical world are central to self-definition and social interaction. The current research analyzes reasoning about three kinds of beliefs: those that concern matters of fact (e.g., dinosaurs are extinct), preference (e.g., green is the prettiest color), and ideology (e.g., there is only one God). The domain of ideology is of unique interest because it is hypothesized to contain elements of both facts and preferences. If adults' distinct reasoning about ideological beliefs is the result of prolonged experience with the physical and social world, children and adults should reveal distinct patterns of differentiating kinds of beliefs, and this difference should be particularly pronounced with respect to ideological beliefs. On the other hand, if adults' reasoning about beliefs is a basic component of social cognition, children and adults should demonstrate similar belief representations and patterns of belief differentiation. Two experiments demonstrate that 5-10 year old children and adults similarly judged religious beliefs to be intermediate between factual beliefs (where two disagreeing people cannot both be right) and preferences (where they can). From the age of 5 years and continuing into adulthood, individuals distinguished ideological beliefs from other types of mental states and demonstrated limited tolerance for belief-based disagreements.

Multivariate pattern classification reveals autonomic and experiential representations of discrete emotions.

PubMed

Kragel, Philip A; Labar, Kevin S

2013-08-01

Defining the structural organization of emotions is a central unresolved question in affective science. In particular, the extent to which autonomic nervous system activity signifies distinct affective states remains controversial. Most prior research on this topic has used univariate statistical approaches in attempts to classify emotions from psychophysiological data. In the present study, electrodermal, cardiac, respiratory, and gastric activity, as well as self-report measures were taken from healthy subjects during the experience of fear, anger, sadness, surprise, contentment, and amusement in response to film and music clips. Information pertaining to affective states present in these response patterns was analyzed using multivariate pattern classification techniques. Overall accuracy for classifying distinct affective states was 58.0% for autonomic measures and 88.2% for self-report measures, both of which were significantly above chance. Further, examining the error distribution of classifiers revealed that the dimensions of valence and arousal selectively contributed to decoding emotional states from self-report, whereas a categorical configuration of affective space was evident in both self-report and autonomic measures. Taken together, these findings extend recent multivariate approaches to study emotion and indicate that pattern classification tools may improve upon univariate approaches to reveal the underlying structure of emotional experience and physiological expression. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Multivariate Pattern Classification Reveals Autonomic and Experiential Representations of Discrete Emotions

PubMed Central

Kragel, Philip A.; LaBar, Kevin S.

2013-01-01

Defining the structural organization of emotions is a central unresolved question in affective science. In particular, the extent to which autonomic nervous system activity signifies distinct affective states remains controversial. Most prior research on this topic has used univariate statistical approaches in attempts to classify emotions from psychophysiological data. In the present study, electrodermal, cardiac, respiratory, and gastric activity, as well as self-report measures were taken from healthy subjects during the experience of fear, anger, sadness, surprise, contentment, and amusement in response to film and music clips. Information pertaining to affective states present in these response patterns was analyzed using multivariate pattern classification techniques. Overall accuracy for classifying distinct affective states was 58.0% for autonomic measures and 88.2% for self-report measures, both of which were significantly above chance. Further, examining the error distribution of classifiers revealed that the dimensions of valence and arousal selectively contributed to decoding emotional states from self-report, whereas a categorical configuration of affective space was evident in both self-report and autonomic measures. Taken together, these findings extend recent multivariate approaches to study emotion and indicate that pattern classification tools may improve upon univariate approaches to reveal the underlying structure of emotional experience and physiological expression. PMID:23527508

Landscape features, standards, and semantics in U.S. national topographic mapping databases

USGS Publications Warehouse

Varanka, Dalia

2009-01-01

The objective of this paper is to examine the contrast between local, field-surveyed topographical representation and feature representation in digital, centralized databases and to clarify their ontological implications. The semantics of these two approaches are contrasted by examining the categorization of features by subject domains inherent to national topographic mapping. When comparing five USGS topographic mapping domain and feature lists, results indicate that multiple semantic meanings and ontology rules were applied to the initial digital database, but were lost as databases became more centralized at national scales, and common semantics were replaced by technological terms.

Maplike representation of celestial E-vector orientations in the brain of an insect.

PubMed

Heinze, Stanley; Homberg, Uwe

2007-02-16

For many insects, the polarization pattern of the blue sky serves as a compass cue for spatial navigation. E-vector orientations are detected by photoreceptors in a dorsal rim area of the eye. Polarized-light signals from both eyes are finally integrated in the central complex, a brain area consisting of two subunits, the protocerebral bridge and the central body. Here we show that a topographic representation of zenithal E-vector orientations underlies the columnar organization of the protocerebral bridge in a locust. The maplike arrangement is highly suited to signal head orientation under the open sky.

The organization of conspecific face space in nonhuman primates

PubMed Central

Parr, Lisa A.; Taubert, Jessica; Little, Anthony C.; Hancock, Peter J. B.

2013-01-01

Humans and chimpanzees demonstrate numerous cognitive specializations for processing faces, but comparative studies with monkeys suggest that these may be the result of recent evolutionary adaptations. The present study utilized the novel approach of face space, a powerful theoretical framework used to understand the representation of face identity in humans, to further explore species differences in face processing. According to the theory, faces are represented by vectors in a multidimensional space, the centre of which is defined by an average face. Each dimension codes features important for describing a face’s identity, and vector length codes the feature’s distinctiveness. Chimpanzees and rhesus monkeys discriminated male and female conspecifics’ faces, rated by humans for their distinctiveness, using a computerized task. Multidimensional scaling analyses showed that the organization of face space was similar between humans and chimpanzees. Distinctive faces had the longest vectors and were the easiest for chimpanzees to discriminate. In contrast, distinctiveness did not correlate with the performance of rhesus monkeys. The feature dimensions for each species’ face space were visualized and described using morphing techniques. These results confirm species differences in the perceptual representation of conspecific faces, which are discussed within an evolutionary framework. PMID:22670823

What makes us conscious of our own agency? And why the conscious versus unconscious representation distinction matters

PubMed Central

Carruthers, Glenn

2014-01-01

Existing accounts of the sense of agency tend to focus on the proximal causal history of the feeling. That is, they explain the sense of agency by describing the cognitive mechanism that causes the sense of agency to be elicited. However, it is possible to elicit an unconscious representation of one’s own agency that plays a different role in a cognitive system. I use the “occasionality problem” to suggest that taking this distinction seriously has potential theoretical pay-offs for this reason. We are faced, then, with a need to distinguish instances of the representation of one’s own agency in which the subject is aware of their sense of own agency from instances in which they are not. This corresponds to a specific instance of what Dennett calls the “Hard Question”: once the representation is elicited, then what happens? In other words, how is a representation of one’s own agency used in a cognitive system when the subject is aware of it? How is this different from when the representation of own agency remains unconscious? This phrasing suggests a Functionalist answer to the Hard Question. I consider two single function hypotheses. First, perhaps the representation of own agency enters into the mechanisms of attention. This seems unlikely as, in general, attention is insufficient for awareness. Second, perhaps, a subject is aware of their sense of agency when it is available for verbal report. However, this seems inconsistent with evidence of a sense of agency in the great apes. Although these two single function views seem like dead ends, multifunction hypotheses such as the global workspace theory remain live options which we should consider. I close by considering a non-functionalist answer to the Hard Question: perhaps it is not a difference in the use to which the representation is put, but a difference in the nature of the representation itself. When it comes to the sense of agency, the Hard Question remains, but there are alternatives open to us. PMID:25002841

What makes us conscious of our own agency? And why the conscious versus unconscious representation distinction matters.

PubMed

Carruthers, Glenn

2014-01-01

Existing accounts of the sense of agency tend to focus on the proximal causal history of the feeling. That is, they explain the sense of agency by describing the cognitive mechanism that causes the sense of agency to be elicited. However, it is possible to elicit an unconscious representation of one's own agency that plays a different role in a cognitive system. I use the "occasionality problem" to suggest that taking this distinction seriously has potential theoretical pay-offs for this reason. We are faced, then, with a need to distinguish instances of the representation of one's own agency in which the subject is aware of their sense of own agency from instances in which they are not. This corresponds to a specific instance of what Dennett calls the "Hard Question": once the representation is elicited, then what happens? In other words, how is a representation of one's own agency used in a cognitive system when the subject is aware of it? How is this different from when the representation of own agency remains unconscious? This phrasing suggests a Functionalist answer to the Hard Question. I consider two single function hypotheses. First, perhaps the representation of own agency enters into the mechanisms of attention. This seems unlikely as, in general, attention is insufficient for awareness. Second, perhaps, a subject is aware of their sense of agency when it is available for verbal report. However, this seems inconsistent with evidence of a sense of agency in the great apes. Although these two single function views seem like dead ends, multifunction hypotheses such as the global workspace theory remain live options which we should consider. I close by considering a non-functionalist answer to the Hard Question: perhaps it is not a difference in the use to which the representation is put, but a difference in the nature of the representation itself. When it comes to the sense of agency, the Hard Question remains, but there are alternatives open to us.

Unitary vs Multiple Semantics: PET Studies of Word and Picture Processing

ERIC Educational Resources Information Center

Bright, P.; Moss, H.; Tyler, L. K.

2004-01-01

In this paper we examine a central issue in cognitive neuroscience: are there separate conceptual representations associated with different input modalities (e.g., Paivio, 1971, 1986; Warrington & Shallice, 1984) or do inputs from different modalities converge on to the same set of representations (e.g., Caramazza, Hillis, Rapp, & Romani, 1990;…

Distinct encoding of risk and value in economic choice between multiple risky options☆

PubMed Central

Wright, Nicholas D.; Symmonds, Mkael; Dolan, Raymond J.

2013-01-01

Neural encoding of value-based stimuli is suggested to involve representations of summary statistics, including risk and expected value (EV). A more complex, but ecologically more common, context is when multiple risky options are evaluated together. However, it is unknown whether encoding related to option evaluation in these situations involves similar principles. Here we employed fMRI during a task that parametrically manipulated EV and risk in two simultaneously presented lotteries, both of which contained either gains or losses. We found representations of EV in medial prefrontal cortex and anterior insula, an encoding that was dependent on which option was chosen (i.e. chosen and unchosen EV) and whether the choice was over gains or losses. Parietal activity reflected whether the riskier or surer option was selected, whilst activity in a network of regions that also included parietal cortex reflected both combined risk and difference in risk for the two options. Our findings provide support for the idea that summary statistics underpin a representation of value-based stimuli, and further that these summary statistics undergo distinct forms of encoding. PMID:23684860

Dyslexia in adults: Evidence for deficits in non-word reading and in the phonological representation of lexical items.

PubMed

Elbro, C; Nielsen, I; Petersen, D K

1994-01-01

Difficulties in reading and language skills which persist from childhood into adult life are the concerns of this article. The aims were twofold: (1) to find measures of adult reading processes that validate adults' retrospective reports of difficulties in learning to read during the school years, and (2) to search for indications of basic deficits in phonological processing that may point toward underlying causes of reading difficulties. Adults who reported a history of difficulties in learning to read (n=102) were distinctly disabled in phonological coding in reading, compared to adults without similar histories (n=56). They were less disabled in the comprehension of written passages, and the comprehension disability was explained by the phonological difficulties. A number of indications were found that adults with poor phonological coding skills in reading (i.e., dyslexia) have basic deficits in phonological representations of spoken words, even when semantic word knowledge, phonemic awareness, educational level, and daily reading habits are taken into account. It is suggested that dyslexics possess less distinct phonological representations of spoken words.

Two Anatomically and Computationally Distinct Learning Signals Predict Changes to Stimulus-Outcome Associations in Hippocampus.

PubMed

Boorman, Erie D; Rajendran, Vani G; O'Reilly, Jill X; Behrens, Tim E

2016-03-16

Complex cognitive processes require sophisticated local processing but also interactions between distant brain regions. It is therefore critical to be able to study distant interactions between local computations and the neural representations they act on. Here we report two anatomically and computationally distinct learning signals in lateral orbitofrontal cortex (lOFC) and the dopaminergic ventral midbrain (VM) that predict trial-by-trial changes to a basic internal model in hippocampus. To measure local computations during learning and their interaction with neural representations, we coupled computational fMRI with trial-by-trial fMRI suppression. We find that suppression in a medial temporal lobe network changes trial-by-trial in proportion to stimulus-outcome associations. During interleaved choice trials, we identify learning signals that relate to outcome type in lOFC and to reward value in VM. These intervening choice feedback signals predicted the subsequent change to hippocampal suppression, suggesting a convergence of signals that update the flexible representation of stimulus-outcome associations. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Agent-specific learning signals for self–other distinction during mentalising

PubMed Central

Dolan, Raymond J.; Kurth-Nelson, Zeb

2018-01-01

Humans have a remarkable ability to simulate the minds of others. How the brain distinguishes between mental states attributed to self and mental states attributed to someone else is unknown. Here, we investigated how fundamental neural learning signals are selectively attributed to different agents. Specifically, we asked whether learning signals are encoded in agent-specific neural patterns or whether a self–other distinction depends on encoding agent identity separately from this learning signal. To examine this, we tasked subjects to learn continuously 2 models of the same environment, such that one was selectively attributed to self and the other was selectively attributed to another agent. Combining computational modelling with magnetoencephalography (MEG) enabled us to track neural representations of prediction errors (PEs) and beliefs attributed to self, and of simulated PEs and beliefs attributed to another agent. We found that the representational pattern of a PE reliably predicts the identity of the agent to whom the signal is attributed, consistent with a neural self–other distinction implemented via agent-specific learning signals. Strikingly, subjects exhibiting a weaker neural self–other distinction also had a reduced behavioural capacity for self–other distinction and displayed more marked subclinical psychopathological traits. The neural self–other distinction was also modulated by social context, evidenced in a significantly reduced decoding of agent identity in a nonsocial control task. Thus, we show that self–other distinction is realised through an encoding of agent identity intrinsic to fundamental learning signals. The observation that the fidelity of this encoding predicts psychopathological traits is of interest as a potential neurocomputational psychiatric biomarker. PMID:29689053

Agent-specific learning signals for self-other distinction during mentalising.

PubMed

Ereira, Sam; Dolan, Raymond J; Kurth-Nelson, Zeb

2018-04-01

Humans have a remarkable ability to simulate the minds of others. How the brain distinguishes between mental states attributed to self and mental states attributed to someone else is unknown. Here, we investigated how fundamental neural learning signals are selectively attributed to different agents. Specifically, we asked whether learning signals are encoded in agent-specific neural patterns or whether a self-other distinction depends on encoding agent identity separately from this learning signal. To examine this, we tasked subjects to learn continuously 2 models of the same environment, such that one was selectively attributed to self and the other was selectively attributed to another agent. Combining computational modelling with magnetoencephalography (MEG) enabled us to track neural representations of prediction errors (PEs) and beliefs attributed to self, and of simulated PEs and beliefs attributed to another agent. We found that the representational pattern of a PE reliably predicts the identity of the agent to whom the signal is attributed, consistent with a neural self-other distinction implemented via agent-specific learning signals. Strikingly, subjects exhibiting a weaker neural self-other distinction also had a reduced behavioural capacity for self-other distinction and displayed more marked subclinical psychopathological traits. The neural self-other distinction was also modulated by social context, evidenced in a significantly reduced decoding of agent identity in a nonsocial control task. Thus, we show that self-other distinction is realised through an encoding of agent identity intrinsic to fundamental learning signals. The observation that the fidelity of this encoding predicts psychopathological traits is of interest as a potential neurocomputational psychiatric biomarker.

The contributions of non-numeric dimensions to number encoding, representations, and decision-making factors.

PubMed

Odic, Darko

2017-01-01

Leibovich et al. suggest that congruency effects in number perception (biases towards smaller, denser, etc., dots) are evidence for the number's dependence on these dimensions. I argue that they fail to differentiate between effects at three distinct levels of number perception - encoding, representations, and decision making - and that differentiating between these allows the number to be independent from, but correlated with, non-numeric dimensions.

Tripartite Governance: Enabling Successful Implementations with Vulnerable Populations.

PubMed

Kennedy, Margaret Ann

2016-01-01

Vulnerable populations are often at a distinct disadvantage when it comes to the implementation of health information systems in an equitable, appropriate, and timely manner. The disadvantages experienced by vulnerable populations are innumerable and include lack of representation, lack of appropriate levels of funding, lack of resources and capacity, and lack of representation. Increasingly, models of representation for complex implementations involve a tripartite project governance model. This tripartite partnership distributes accountability across all partners, and ensures that vulnerable populations have an equitable contribution to the direction of implementation according to their needs. This article shares lessons learned and best practices from complex tripartite partnerships supporting implementations with vulnerable populations in Canada.

Peripheral Nerve Injury in Developing Rats Reorganizes Representation Pattern in Motor Cortex

NASA Astrophysics Data System (ADS)

Donoghue, John P.; Sanes, Jerome N.

1987-02-01

We investigated the effect of neonatal nerve lesions on cerebral motor cortex organization by comparing the cortical motor representation of normal adult rats with adult rats that had one forelimb removed on the day of birth. Mapping of cerebral neocortex with electrical stimulation revealed an altered relationship between the motor cortex and the remaining muscles. Whereas distal forelimb movements are normally elicited at the lowest threshold in the motor cortex forelimb area, the same stimuli activated shoulder and trunk muscles in experimental animals. In addition, an expanded cortical representation of intact body parts was present and there was an absence of a distinct portion of motor cortex. These data demonstrate that representation patterns in motor cortex can be altered by peripheral nerve injury during development.

Verifying the equivalence of representations of the knee joint moment vector from a drop vertical jump task.

PubMed

Nichols, Julia K; O'Reilly, Oliver M

2017-03-01

Biomechanics software programs, such as Visual3D, Nexus, Cortex, and OpenSim, have the capability of generating several distinct component representations for joint moments and forces from motion capture data. These representations include those for orthonormal proximal and distal coordinate systems and a non-orthogonal joint coordinate system. In this article, a method is presented to address the challenging problem of evaluating and verifying the equivalence of these representations. The method accommodates the difficulty that there are two possible sets of non-orthogonal basis vectors that can be used to express a vector in the joint coordinate system and is illuminated using motion capture data from a drop vertical jump task. Copyright © 2016 Elsevier B.V. All rights reserved.

Adinkra (in)equivalence from Coxeter group representations: A case study

NASA Astrophysics Data System (ADS)

Chappell, Isaac; Gates, S. James; Hübsch, T.

2014-02-01

Using a MathematicaTM code, we present a straightforward numerical analysis of the 384-dimensional solution space of signed permutation 4×4 matrices, which in sets of four, provide representations of the 𝒢ℛ(4, 4) algebra, closely related to the 𝒩 = 1 (simple) supersymmetry algebra in four-dimensional space-time. Following after ideas discussed in previous papers about automorphisms and classification of adinkras and corresponding supermultiplets, we make a new and alternative proposal to use equivalence classes of the (unsigned) permutation group S4 to define distinct representations of higher-dimensional spin bundles within the context of adinkras. For this purpose, the definition of a dual operator akin to the well-known Hodge star is found to partition the space of these 𝒢ℛ(4, 4) representations into three suggestive classes.

Hexagonal wavelet processing of digital mammography

NASA Astrophysics Data System (ADS)

Laine, Andrew F.; Schuler, Sergio; Huda, Walter; Honeyman-Buck, Janice C.; Steinbach, Barbara G.

1993-09-01

This paper introduces a novel approach for accomplishing mammographic feature analysis through overcomplete multiresolution representations. We show that efficient representations may be identified from digital mammograms and used to enhance features of importance to mammography within a continuum of scale-space. We present a method of contrast enhancement based on an overcomplete, non-separable multiscale representation: the hexagonal wavelet transform. Mammograms are reconstructed from transform coefficients modified at one or more levels by local and global non-linear operators. Multiscale edges identified within distinct levels of transform space provide local support for enhancement. We demonstrate that features extracted from multiresolution representations can provide an adaptive mechanism for accomplishing local contrast enhancement. We suggest that multiscale detection and local enhancement of singularities may be effectively employed for the visualization of breast pathology without excessive noise amplification.

Distinct Pattern Separation Related Transfer Functions in Human CA3/Dentate and CA1 Revealed Using High-Resolution fMRI and Variable Mnemonic Similarity

ERIC Educational Resources Information Center

Lacy, Joyce W.; Yassa, Michael A.; Stark, Shauna M.; Muftuler, L. Tugan; Stark, Craig E. L.

2011-01-01

Producing and maintaining distinct (orthogonal) neural representations for similar events is critical to avoiding interference in long-term memory. Recently, our laboratory provided the first evidence for separation-like signals in the human CA3/dentate. Here, we extended this by parametrically varying the change in input (similarity) while…

Neural representations of magnitude for natural and rational numbers.

PubMed

DeWolf, Melissa; Chiang, Jeffrey N; Bassok, Miriam; Holyoak, Keith J; Monti, Martin M

2016-11-01

Humans have developed multiple symbolic representations for numbers, including natural numbers (positive integers) as well as rational numbers (both fractions and decimals). Despite a considerable body of behavioral and neuroimaging research, it is currently unknown whether different notations map onto a single, fully abstract, magnitude code, or whether separate representations exist for specific number types (e.g., natural versus rational) or number representations (e.g., base-10 versus fractions). We address this question by comparing brain metabolic response during a magnitude comparison task involving (on different trials) integers, decimals, and fractions. Univariate and multivariate analyses revealed that the strength and pattern of activation for fractions differed systematically, within the intraparietal sulcus, from that of both decimals and integers, while the latter two number representations appeared virtually indistinguishable. These results demonstrate that the two major notations formats for rational numbers, fractions and decimals, evoke distinct neural representations of magnitude, with decimals representations being more closely linked to those of integers than to those of magnitude-equivalent fractions. Our findings thus suggest that number representation (base-10 versus fractions) is an important organizational principle for the neural substrate underlying mathematical cognition. Copyright © 2016 Elsevier Inc. All rights reserved.

On the Representational Systems Underlying Prospection: Evidence from the Event-Cueing Paradigm

ERIC Educational Resources Information Center

D'Argembeau, Arnaud; Demblon, Julie

2012-01-01

The ability to think about the future--prospection--is central to many aspects of human cognition and behavior, from planning and decision making, to self-control and the construction of a sense of identity. Yet, the exact nature of the representational systems underlying prospection is not fully understood. Recent findings point to the critical…

Teaching with External Representations: The Case of a Common Energy-Level Diagram in Chemistry

ERIC Educational Resources Information Center

Orgill, MaryKay; Crippen, Kent

2010-01-01

Diagrams and figures play a central role in science and science education. Research has indicated that, when presented and used properly in a classroom setting, these external representations can contribute to students' understanding of scientific concepts; however, it is apparent that students do not always use, understand, interpret, or value…

An Examination of Connections in Mathematical Processes in Students' Problem Solving: Connections between Representing and Justifying

ERIC Educational Resources Information Center

Stylianou, Despina A.

2013-01-01

Representation and justification are two central "mathematical practices". In the past, each has been examined to gain insights in the functions that they have in students' mathematical problem solving. Here, we examine the ways that representation and justification interact and influence the development of one another. We focus on the…

Students' Competencies in Working with Functions in Secondary Mathematics Education-Empirical Examination of a Competence Structure Model

ERIC Educational Resources Information Center

Nitsch, Renate; Fredebohm, Anneke; Bruder, Regina; Kelava, Augustin; Naccarella, Dominik; Leuders, Timo; Wirtz, Markus

2015-01-01

In the subject matter of functional relationships, a student's ability to translate from one form of representation to another is seen as a central competence. In the course of the HEUREKO project (heuristic work with representations of functional relationships and the diagnosis of mathematical competencies of students), a theoretical competence…

The organization of the human cerebellum estimated by intrinsic functional connectivity

PubMed Central

Krienen, Fenna M.; Castellanos, Angela; Diaz, Julio C.; Yeo, B. T. Thomas

2011-01-01

The cerebral cortex communicates with the cerebellum via polysynaptic circuits. Separate regions of the cerebellum are connected to distinct cerebral areas, forming a complex topography. In this study we explored the organization of cerebrocerebellar circuits in the human using resting-state functional connectivity MRI (fcMRI). Data from 1,000 subjects were registered using nonlinear deformation of the cerebellum in combination with surface-based alignment of the cerebral cortex. The foot, hand, and tongue representations were localized in subjects performing movements. fcMRI maps derived from seed regions placed in different parts of the motor body representation yielded the expected inverted map of somatomotor topography in the anterior lobe and the upright map in the posterior lobe. Next, we mapped the complete topography of the cerebellum by estimating the principal cerebral target for each point in the cerebellum in a discovery sample of 500 subjects and replicated the topography in 500 independent subjects. The majority of the human cerebellum maps to association areas. Quantitative analysis of 17 distinct cerebral networks revealed that the extent of the cerebellum dedicated to each network is proportional to the network's extent in the cerebrum with a few exceptions, including primary visual cortex, which is not represented in the cerebellum. Like somatomotor representations, cerebellar regions linked to association cortex have separate anterior and posterior representations that are oriented as mirror images of one another. The orderly topography of the representations suggests that the cerebellum possesses at least two large, homotopic maps of the full cerebrum and possibly a smaller third map. PMID:21795627

Daytime Sleep Enhances Consolidation of the Spatial but Not Motoric Representation of Motor Sequence Memory

PubMed Central

Albouy, Geneviève; Fogel, Stuart; Pottiez, Hugo; Nguyen, Vo An; Ray, Laura; Lungu, Ovidiu; Carrier, Julie; Robertson, Edwin; Doyon, Julien

2013-01-01

Motor sequence learning is known to rely on more than a single process. As the skill develops with practice, two different representations of the sequence are formed: a goal representation built under spatial allocentric coordinates and a movement representation mediated through egocentric motor coordinates. This study aimed to explore the influence of daytime sleep (nap) on consolidation of these two representations. Through the manipulation of an explicit finger sequence learning task and a transfer protocol, we show that both allocentric (spatial) and egocentric (motor) representations of the sequence can be isolated after initial training. Our results also demonstrate that nap favors the emergence of offline gains in performance for the allocentric, but not the egocentric representation, even after accounting for fatigue effects. Furthermore, sleep-dependent gains in performance observed for the allocentric representation are correlated with spindle density during non-rapid eye movement (NREM) sleep of the post-training nap. In contrast, performance on the egocentric representation is only maintained, but not improved, regardless of the sleep/wake condition. These results suggest that motor sequence memory acquisition and consolidation involve distinct mechanisms that rely on sleep (and specifically, spindle) or simple passage of time, depending respectively on whether the sequence is performed under allocentric or egocentric coordinates. PMID:23300993

Centrality in earthquake multiplex networks

NASA Astrophysics Data System (ADS)

Lotfi, Nastaran; Darooneh, Amir Hossein; Rodrigues, Francisco A.

2018-06-01

Seismic time series has been mapped as a complex network, where a geographical region is divided into square cells that represent the nodes and connections are defined according to the sequence of earthquakes. In this paper, we map a seismic time series to a temporal network, described by a multiplex network, and characterize the evolution of the network structure in terms of the eigenvector centrality measure. We generalize previous works that considered the single layer representation of earthquake networks. Our results suggest that the multiplex representation captures better earthquake activity than methods based on single layer networks. We also verify that the regions with highest seismological activities in Iran and California can be identified from the network centrality analysis. The temporal modeling of seismic data provided here may open new possibilities for a better comprehension of the physics of earthquakes.

Using Fuzzy-Trace Theory to Understand and Improve Health Judgments, Decisions, and Behaviors: A Literature Review

PubMed Central

Blalock, Susan J.; Reyna, Valerie F.

2016-01-01

Objective Fuzzy-trace theory is a dual-process model of memory, reasoning, judgment, and decision making that contrasts with traditional expectancy-value approaches. We review the literature applying fuzzy-trace theory to health with three aims: evaluating whether the theory’s basic distinctions have been validated empirically in the domain of health; determining whether these distinctions are useful in assessing, explaining, and predicting health-related psychological processes; and determining whether the theory can be used to improve health judgments, decisions, or behaviors, especially in comparison to other approaches. Methods We conducted a literature review using PubMed, PsycInfo, and Web of Science to identify empirical peer-reviewed papers that applied fuzzy-trace theory, or central constructs of the theory, to investigate health judgments, decisions, or behaviors. Results 79 studies were identified, over half published since 2012, spanning a wide variety of conditions and populations. Study findings supported the prediction that verbatim and gist representations are distinct constructs that can be retrieved independently using different cues. Although gist-based reasoning was usually associated with improved judgment and decision making, four sources of bias that can impair gist reasoning were identified. Finally, promising findings were reported from intervention studies that used fuzzy-trace theory to improve decision making and decrease unhealthy risk taking. Conclusions Despite large gaps in the literature, most studies supported all three aims. By focusing on basic psychological processes that underlie judgment and decision making, fuzzy-trace theory provides insights into how individuals make decisions involving health risks and suggests innovative intervention approaches to improve health outcomes. PMID:27505197

Dynamics of Gut-Brain Communication Underlying Hunger.

PubMed

Beutler, Lisa R; Chen, Yiming; Ahn, Jamie S; Lin, Yen-Chu; Essner, Rachel A; Knight, Zachary A

2017-10-11

Communication between the gut and brain is critical for homeostasis, but how this communication is represented in the dynamics of feeding circuits is unknown. Here we describe nutritional regulation of key neurons that control hunger in vivo. We show that intragastric nutrient infusion rapidly and durably inhibits hunger-promoting AgRP neurons in awake, behaving mice. This inhibition is proportional to the number of calories infused but surprisingly independent of macronutrient identity or nutritional state. We show that three gastrointestinal signals-serotonin, CCK, and PYY-are necessary or sufficient for these effects. In contrast, the hormone leptin has no acute effect on dynamics of these circuits or their sensory regulation but instead induces a slow modulation that develops over hours and is required for inhibition of feeding. These findings reveal how layers of visceral signals operating on distinct timescales converge on hypothalamic feeding circuits to generate a central representation of energy balance. Copyright © 2017 Elsevier Inc. All rights reserved.

77 FR 64316 - Endangered and Threatened Species; Recovery Plan South-Central California Coast Steelhead...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-19

... and Threatened Species; Recovery Plan South-Central California Coast Steelhead Distinct Population... Coast (SCCCS) (Oncorhynchus mykiss) Distinct Population (DPS). NMFS is soliciting review and comment... plan development. NMFS is hereby soliciting relevant information on SCCC Steelhead DPS populations and...

Mentalizing regions represent distributed, continuous, and abstract dimensions of others' beliefs.

PubMed

Koster-Hale, Jorie; Richardson, Hilary; Velez, Natalia; Asaba, Mika; Young, Liane; Saxe, Rebecca

2017-11-01

The human capacity to reason about others' minds includes making causal inferences about intentions, beliefs, values, and goals. Previous fMRI research has suggested that a network of brain regions, including bilateral temporo-parietal junction (TPJ), superior temporal sulcus (STS), and medial prefrontal-cortex (MPFC), are reliably recruited for mental state reasoning. Here, in two fMRI experiments, we investigate the representational content of these regions. Building on existing computational and neural evidence, we hypothesized that social brain regions contain at least two functionally and spatially distinct components: one that represents information related to others' motivations and values, and another that represents information about others' beliefs and knowledge. Using multi-voxel pattern analysis, we find evidence that motivational versus epistemic features are independently represented by theory of mind (ToM) regions: RTPJ contains information about the justification of the belief, bilateral TPJ represents the modality of the source of knowledge, and VMPFC represents the valence of the resulting emotion. These representations are found only in regions implicated in social cognition and predict behavioral responses at the level of single items. We argue that cortical regions implicated in mental state inference contain complementary, but distinct, representations of epistemic and motivational features of others' beliefs, and that, mirroring the processes observed in sensory systems, social stimuli are represented in distinct and distributed formats across the human brain. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

[Parietal Cortices and Body Information].

PubMed

Naito, Eiichi; Amemiya, Kaoru; Morita, Tomoyo

2016-11-01

Proprioceptive signals originating from skeletal muscles and joints contribute to the formation of both the human body schema and the body image. In this chapter, we introduce various types of bodily illusions that are elicited by proprioceptive inputs, and we discuss distinct functions implemented by different parietal cortices. First, we illustrate the primary importance of the motor network in the processing of proprioceptive (kinesthetic) signals originating from muscle spindles. Next, we argue that the right inferior parietal cortex, in concert with the inferior frontal cortex (both regions connected by the inferior branch of the superior longitudinal fasciculus-SLF III), may be involved in the conscious experience of body image. Further, we hypothesize other functions of distinct parietal regions: the association between internal hand motor representation with external object representation in the left inferior parietal cortex, visuo-kinesthetic processing in the bilateral posterior parietal cortices, and the integration of somatic signals from different body parts in the higher-order somatosensory parietal cortices. Our results indicate that a distinct parietal region, in concert with its anatomically and functionally connected frontal regions, probably plays specialized roles in the processing of body-related information.

Basic level category structure emerges gradually across human ventral visual cortex.

PubMed

Iordan, Marius Cătălin; Greene, Michelle R; Beck, Diane M; Fei-Fei, Li

2015-07-01

Objects can be simultaneously categorized at multiple levels of specificity ranging from very broad ("natural object") to very distinct ("Mr. Woof"), with a mid-level of generality (basic level: "dog") often providing the most cognitively useful distinction between categories. It is unknown, however, how this hierarchical representation is achieved in the brain. Using multivoxel pattern analyses, we examined how well each taxonomic level (superordinate, basic, and subordinate) of real-world object categories is represented across occipitotemporal cortex. We found that, although in early visual cortex objects are best represented at the subordinate level (an effect mostly driven by low-level feature overlap between objects in the same category), this advantage diminishes compared to the basic level as we move up the visual hierarchy, disappearing in object-selective regions of occipitotemporal cortex. This pattern stems from a combined increase in within-category similarity (category cohesion) and between-category dissimilarity (category distinctiveness) of neural activity patterns at the basic level, relative to both subordinate and superordinate levels, suggesting that successive visual areas may be optimizing basic level representations.

Goal-Directed Visual Processing Differentially Impacts Human Ventral and Dorsal Visual Representations

PubMed Central

2017-01-01

Recent studies have challenged the ventral/“what” and dorsal/“where” two-visual-processing-pathway view by showing the existence of “what” and “where” information in both pathways. Is the two-pathway distinction still valid? Here, we examined how goal-directed visual information processing may differentially impact visual representations in these two pathways. Using fMRI and multivariate pattern analysis, in three experiments on human participants (57% females), by manipulating whether color or shape was task-relevant and how they were conjoined, we examined shape-based object category decoding in occipitotemporal and parietal regions. We found that object category representations in all the regions examined were influenced by whether or not object shape was task-relevant. This task effect, however, tended to decrease as task-relevant and irrelevant features were more integrated, reflecting the well-known object-based feature encoding. Interestingly, task relevance played a relatively minor role in driving the representational structures of early visual and ventral object regions. They were driven predominantly by variations in object shapes. In contrast, the effect of task was much greater in dorsal than ventral regions, with object category and task relevance both contributing significantly to the representational structures of the dorsal regions. These results showed that, whereas visual representations in the ventral pathway are more invariant and reflect “what an object is,” those in the dorsal pathway are more adaptive and reflect “what we do with it.” Thus, despite the existence of “what” and “where” information in both visual processing pathways, the two pathways may still differ fundamentally in their roles in visual information representation. SIGNIFICANCE STATEMENT Visual information is thought to be processed in two distinctive pathways: the ventral pathway that processes “what” an object is and the dorsal pathway that processes “where” it is located. This view has been challenged by recent studies revealing the existence of “what” and “where” information in both pathways. Here, we found that goal-directed visual information processing differentially modulates shape-based object category representations in the two pathways. Whereas ventral representations are more invariant to the demand of the task, reflecting what an object is, dorsal representations are more adaptive, reflecting what we do with the object. Thus, despite the existence of “what” and “where” information in both pathways, visual representations may still differ fundamentally in the two pathways. PMID:28821655

41 CFR Appendix C to Chapter 301 - Standard Data Elements for Federal Travel [Traveler Identification

Code of Federal Regulations, 2010 CFR

2010-07-01

... Method employee used to purchase transportation tickets Method Indicator GTR U.S. Government Transportation Request Central Billing Account A contractor centrally billed account Government Charge Card In.../Date Fields Claimant Signature Traveler's signature, or digital representation. The signature signifies...

Multivariate Brain Prediction of Heart Rate and Skin Conductance Responses to Social Threat.

PubMed

Eisenbarth, Hedwig; Chang, Luke J; Wager, Tor D

2016-11-23

Psychosocial stressors induce autonomic nervous system (ANS) responses in multiple body systems that are linked to health risks. Much work has focused on the common effects of stress, but ANS responses in different body systems are dissociable and may result from distinct patterns of cortical-subcortical interactions. Here, we used machine learning to develop multivariate patterns of fMRI activity predictive of heart rate (HR) and skin conductance level (SCL) responses during social threat in humans (N = 18). Overall, brain patterns predicted both HR and SCL in cross-validated analyses successfully (r HR = 0.54, r SCL = 0.58, both p < 0.0001). These patterns partly reflected central stress mechanisms common to both responses because each pattern predicted the other signal to some degree (r HR→SCL = 0.21 and r SCL→HR = 0.22, both p < 0.01), but they were largely physiological response specific. Both patterns included positive predictive weights in dorsal anterior cingulate and cerebellum and negative weights in ventromedial PFC and local pattern similarity analyses within these regions suggested that they encode common central stress mechanisms. However, the predictive maps and searchlight analysis suggested that the patterns predictive of HR and SCL were substantially different across most of the brain, including significant differences in ventromedial PFC, insula, lateral PFC, pre-SMA, and dmPFC. Overall, the results indicate that specific patterns of cerebral activity track threat-induced autonomic responses in specific body systems. Physiological measures of threat are not interchangeable, but rather reflect specific interactions among brain systems. We show that threat-induced increases in heart rate and skin conductance share some common representations in the brain, located mainly in the vmPFC, temporal and parahippocampal cortices, thalamus, and brainstem. However, despite these similarities, the brain patterns that predict these two autonomic responses are largely distinct. This evidence for largely output-measure-specific regulation of autonomic responses argues against a common system hypothesis and provides evidence that different autonomic measures reflect distinct, measurable patterns of cortical-subcortical interactions. Copyright © 2016 the authors 0270-6474/16/3611987-12$15.00/0.

Design of a Digital Library for Human Movement.

ERIC Educational Resources Information Center

Ben-Arie, Jezekiel; Pandit, Purvin; Rajaram, ShyamSundar

This paper is focused on a central aspect in the design of a planned digital library for human movement, i.e. on the aspect of representation and recognition of human activity from video data. The method of representation is important since it has a major impact on the design of all the other building blocks of the system such as the user…

Central representation of sensory inputs from the cardio-renal system in Aplysia depilans.

PubMed

Rózsa, K S; Salánki, J; Véró, M; Kovacević, N; Konjevic, D

1980-01-01

Studying the central representation of sensory inputs originating from the heart in Aplysia depilans, it was found that: 1. Neurons responding to heart stimulation can be found in the abdominal, pedal and pleural ganglia alike. 2. The representation of heart input signals was more abundant in the left hemisphere of the abdominal ganglion and in the left pedal and pleural ganglia. 3. The giant neurons of Aplysia depilans can be compared to the homologous cells of Aplysia californica. Two motoneurons (RBHE, LDHI) and one interneuron (L10) proved to be identical in the two subspecies. 4. Sensory inputs originating from the heart may modify the pattern of both heart regulatory motoneurons and interneurons. 5. Nine giant and 19 small neurons of the abdominal ganglion, 3--3 neurons of the right and left pleural ganglion, 6 neurons of the left pedal ganglion responded to heart stimulation. 6. The bursting patterns of cells R15 and L4 were modified to tonic discharge in response to heart stimulation. 7. The representation of sensory inputs originating from the heart is scattered throughout the CNS of Aplysia depilans and heart regulation is based on a feedback mechanism similar to that found in other gastropod species.

Efficient High Order Central Schemes for Multi-Dimensional Hamilton-Jacobi Equations: Talk Slides

NASA Technical Reports Server (NTRS)

Bryson, Steve; Levy, Doron; Biegel, Brian R. (Technical Monitor)

2002-01-01

This viewgraph presentation presents information on the attempt to produce high-order, efficient, central methods that scale well to high dimension. The central philosophy is that the equations should evolve to the point where the data is smooth. This is accomplished by a cyclic pattern of reconstruction, evolution, and re-projection. One dimensional and two dimensional representational methods are detailed, as well.

A Discussion on Uncertainty Representation and Interpretation in Model-Based Prognostics Algorithms based on Kalman Filter Estimation Applied to Prognostics of Electronics Components

NASA Technical Reports Server (NTRS)

Celaya, Jose R.; Saxen, Abhinav; Goebel, Kai

2012-01-01

This article discusses several aspects of uncertainty representation and management for model-based prognostics methodologies based on our experience with Kalman Filters when applied to prognostics for electronics components. In particular, it explores the implications of modeling remaining useful life prediction as a stochastic process and how it relates to uncertainty representation, management, and the role of prognostics in decision-making. A distinction between the interpretations of estimated remaining useful life probability density function and the true remaining useful life probability density function is explained and a cautionary argument is provided against mixing interpretations for the two while considering prognostics in making critical decisions.

Internal representations reveal cultural diversity in expectations of facial expressions of emotion.

PubMed

Jack, Rachael E; Caldara, Roberto; Schyns, Philippe G

2012-02-01

Facial expressions have long been considered the "universal language of emotion." Yet consistent cultural differences in the recognition of facial expressions contradict such notions (e.g., R. E. Jack, C. Blais, C. Scheepers, P. G. Schyns, & R. Caldara, 2009). Rather, culture--as an intricate system of social concepts and beliefs--could generate different expectations (i.e., internal representations) of facial expression signals. To investigate, they used a powerful psychophysical technique (reverse correlation) to estimate the observer-specific internal representations of the 6 basic facial expressions of emotion (i.e., happy, surprise, fear, disgust, anger, and sad) in two culturally distinct groups (i.e., Western Caucasian [WC] and East Asian [EA]). Using complementary statistical image analyses, cultural specificity was directly revealed in these representations. Specifically, whereas WC internal representations predominantly featured the eyebrows and mouth, EA internal representations showed a preference for expressive information in the eye region. Closer inspection of the EA observer preference revealed a surprising feature: changes of gaze direction, shown primarily among the EA group. For the first time, it is revealed directly that culture can finely shape the internal representations of common facial expressions of emotion, challenging notions of a biologically hardwired "universal language of emotion."

Computer Icons and the Art of Memory.

ERIC Educational Resources Information Center

McNair, John R.

1996-01-01

States that key aspects of "memoria," the ancient Art of Memory, especially its focus on vivid representational images set against distinct backgrounds, can be helpful in creating memorable, universal, and easily retrievable computer icons. (PA)

Neural representations of emotion are organized around abstract event features.

PubMed

Skerry, Amy E; Saxe, Rebecca

2015-08-03

Research on emotion attribution has tended to focus on the perception of overt expressions of at most five or six basic emotions. However, our ability to identify others' emotional states is not limited to perception of these canonical expressions. Instead, we make fine-grained inferences about what others feel based on the situations they encounter, relying on knowledge of the eliciting conditions for different emotions. In the present research, we provide convergent behavioral and neural evidence concerning the representations underlying these concepts. First, we find that patterns of activity in mentalizing regions contain information about subtle emotional distinctions conveyed through verbal descriptions of eliciting situations. Second, we identify a space of abstract situation features that well captures the emotion discriminations subjects make behaviorally and show that this feature space outperforms competing models in capturing the similarity space of neural patterns in these regions. Together, the data suggest that our knowledge of others' emotions is abstract and high dimensional, that brain regions selective for mental state reasoning support relatively subtle distinctions between emotion concepts, and that the neural representations in these regions are not reducible to more primitive affective dimensions such as valence and arousal. Copyright © 2015 Elsevier Ltd. All rights reserved.

Neural Representations of Emotion Are Organized around Abstract Event Features

PubMed Central

Skerry, Amy E.; Saxe, Rebecca

2016-01-01

Summary Research on emotion attribution has tended to focus on the perception of overt expressions of at most five or six basic emotions. However, our ability to identify others' emotional states is not limited to perception of these canonical expressions. Instead, we make fine-grained inferences about what others feel based on the situations they encounter, relying on knowledge of the eliciting conditions for different emotions. In the present research, we provide convergent behavioral and neural evidence concerning the representations underlying these concepts. First, we find that patterns of activity in mentalizing regions contain information about subtle emotional distinctions conveyed through verbal descriptions of eliciting situations. Second, we identify a space of abstract situation features that well captures the emotion discriminations subjects make behaviorally and show that this feature space outperforms competing models in capturing the similarity space of neural patterns in these regions. Together, the data suggest that our knowledge of others' emotions is abstract and high dimensional, that brain regions selective for mental state reasoning support relatively subtle distinctions between emotion concepts, and that the neural representations in these regions are not reducible to more primitive affective dimensions such as valence and arousal. PMID:26212878

Segmentation of High Angular Resolution Diffusion MRI using Sparse Riemannian Manifold Clustering

PubMed Central

Wright, Margaret J.; Thompson, Paul M.; Vidal, René

2015-01-01

We address the problem of segmenting high angular resolution diffusion imaging (HARDI) data into multiple regions (or fiber tracts) with distinct diffusion properties. We use the orientation distribution function (ODF) to represent HARDI data and cast the problem as a clustering problem in the space of ODFs. Our approach integrates tools from sparse representation theory and Riemannian geometry into a graph theoretic segmentation framework. By exploiting the Riemannian properties of the space of ODFs, we learn a sparse representation for each ODF and infer the segmentation by applying spectral clustering to a similarity matrix built from these representations. In cases where regions with similar (resp. distinct) diffusion properties belong to different (resp. same) fiber tracts, we obtain the segmentation by incorporating spatial and user-specified pairwise relationships into the formulation. Experiments on synthetic data evaluate the sensitivity of our method to image noise and the presence of complex fiber configurations, and show its superior performance compared to alternative segmentation methods. Experiments on phantom and real data demonstrate the accuracy of the proposed method in segmenting simulated fibers, as well as white matter fiber tracts of clinical importance in the human brain. PMID:24108748

Adults with Specific Language Impairment fail to consolidate speech sounds during sleep.

PubMed

Earle, F Sayako; Landi, Nicole; Myers, Emily B

2018-02-14

Specific Language Impairment (SLI) is a common learning disability that is associated with poor speech sound representations. These differences in representational quality are thought to impose a burden on spoken language processing. The underlying mechanism to account for impoverished speech sound representations remains in debate. Previous findings that implicate sleep as important for building speech representations, combined with reports of atypical sleep in SLI, motivate the current investigation into a potential consolidation mechanism as a source of impoverished representations in SLI. In the current study, we trained individuals with SLI on a new (nonnative) set of speech sounds, and tracked their perceptual accuracy and neural responses to these sounds over two days. Adults with SLI achieved comparable performance to typical controls during training, however demonstrated a distinct lack of overnight gains on the next day. We propose that those with SLI may be impaired in the consolidation of acoustic-phonetic information. Published by Elsevier B.V.

Ventromedial Frontal Lobe Damage Alters how Specific Attributes are Weighed in Subjective Valuation.

PubMed

Vaidya, Avinash R; Sefranek, Marcus; Fellows, Lesley K

2017-10-23

The concept of subjective value is central to current neurobiological views of economic decision-making. Much of this work has focused on signals in the ventromedial frontal lobe (VMF) that correlate with the subjective value of a variety of stimuli (e.g., food, monetary gambles), and are thought to support decision-making. However, the neural processes involved in assessing and integrating value information from the attributes of such complex options remain to be defined. Here, we tested the necessary role of VMF in weighting attributes of naturalistic stimuli during value judgments. We asked how distinct attributes of visual artworks influenced the subjective value ratings of subjects with VMF damage, compared to healthy participants and a frontal lobe damaged control group. Subjects with VMF damage were less influenced by the energy (emotion, complexity) and color radiance (warmth, saturation) of the artwork, while they were similar to control groups in considering saliency, balance and concreteness. These dissociations argue that VMF is critical for allowing certain affective content to influence subjective value, while sparing the influence of perceptual or representational information. These distinctions are important for better defining the often-underspecified concept of subjective value and developing more detailed models of the brain mechanisms underlying decision behavior. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Analyzing pitch chroma and pitch height in the human brain.

PubMed

Warren, Jason D; Uppenkamp, Stefan; Patterson, Roy D; Griffiths, Timothy D

2003-11-01

The perceptual pitch dimensions of chroma and height have distinct representations in the human brain: chroma is represented in cortical areas anterior to primary auditory cortex, whereas height is represented posterior to primary auditory cortex.

Balkanizing the primate orbitofrontal cortex: Distinct subregions for comparing and contrasting values

PubMed Central

Rudebeck, Peter H.; Murray, Elisabeth A.

2014-01-01

The primate orbitofrontal cortex (OFC) is often treated as a single entity, but architectonic and connectional neuroanatomy indicates that it has distinguishable parts. Nevertheless, few studies have attempted to dissociate the functions of its subregions. Here we review findings from recent neuropsychological and neurophysiological studies that do so. The lateral OFC seems to be important for learning, representing and updating specific object–reward associations. Medial OFC seems to be important for value comparisons and choosing among objects on that basis. Rather than viewing this dissociation of function in terms of learning versus choosing, however, we suggest that it reflects the distinction between contrasts and comparisons: differences versus similarities. Making use of high-dimensional representations that arise from the convergence of several sensory modalities, the lateral OFC encodes contrasts among outcomes. The medial MFC reduces these contrasting representations of value to a single dimension, a common currency, in order to compare alternative choices. PMID:22145870

Neural priming in human frontal cortex: multiple forms of learning reduce demands on the prefrontal executive system.

PubMed

Race, Elizabeth A; Shanker, Shanti; Wagner, Anthony D

2009-09-01

Past experience is hypothesized to reduce computational demands in PFC by providing bottom-up predictive information that informs subsequent stimulus-action mapping. The present fMRI study measured cortical activity reductions ("neural priming"/"repetition suppression") during repeated stimulus classification to investigate the mechanisms through which learning from the past decreases demands on the prefrontal executive system. Manipulation of learning at three levels of representation-stimulus, decision, and response-revealed dissociable neural priming effects in distinct frontotemporal regions, supporting a multiprocess model of neural priming. Critically, three distinct patterns of neural priming were identified in lateral frontal cortex, indicating that frontal computational demands are reduced by three forms of learning: (a) cortical tuning of stimulus-specific representations, (b) retrieval of learned stimulus-decision mappings, and (c) retrieval of learned stimulus-response mappings. The topographic distribution of these neural priming effects suggests a rostrocaudal organization of executive function in lateral frontal cortex.

Knowledge Representation and Care Planning for Population Health Management.

PubMed

Merahn, Steven

2015-01-01

The traditional organizing principles of medical knowledge may be insufficient to allow for problem representations that are relevant to solution development in emerging models of care such as population health management. Operational classification and central management of clinical and quality objectives and associated strategies will allow for productive innovation in care design and better support goal-directed collaboration among patients and their health resource communities.

Increasing High School Students' Chemistry Performance and Reducing Cognitive Load through an Instructional Strategy Based on the Interaction of Multiple Levels of Knowledge Representation

ERIC Educational Resources Information Center

Milenkovic´, Dus?ica D.; Segedinac, Mirjana D.; Hrin, Tamara N.

2014-01-01

The central goal of this study was to examine the extent to which a teaching approach focused on the interaction between macroscopic, submicroscopic, and symbolic levels of chemistry representations could affect high school students' performance in the field of inorganic reactions, as well as to examine how the applied instruction influences…

Coordinated Excitation and Inhibition of Prefrontal Ensembles During Awake Hippocampal Sharp-Wave Ripple Events

PubMed Central

Jadhav, Shantanu P.; Rothschild, Gideon; Roumis, Demetris K.; Frank, Loren M.

2016-01-01

SUMMARY Interactions between the hippocampus and prefrontal cortex (PFC) are critical for learning and memory. Hippocampal activity during awake sharp wave ripple (SWR) events is important for spatial learning, and hippocampal SWR activity often represents past or potential future experiences. Whether or how this reactivation engages the PFC, and how reactivation might interact with ongoing patterns of PFC activity remains unclear. We recorded hippocampal CA1 and PFC activity in animals learning spatial tasks and found that many PFC cells showed spiking modulation during SWRs. Unlike in CA1, SWR-related activity in PFC comprised both excitation and inhibition of distinct populations. Within individual SWRs, excitation activated PFC cells with representations related to the concurrently reactivated hippocampal representation, while inhibition suppressed PFC cells with unrelated representations. Thus, awake SWRs mark times of strong coordination between hippocampus and PFC that reflects structured reactivation of representations related to ongoing experience. PMID:26971950

Hegemonic and polemical beliefs: culture and consumption in the social representation of wine.

PubMed

Lo Monaco, Grégory; Guimelli, Christian

2011-05-01

Wine, in France, is a cultural product. However, the issue of wine consumption has been at the centre of a recurring social debate. We decided to focus our study on the effect of consumption practices on this social representation as well as the variations in position-taking in very different normative contexts. Results revealed two distinct social representations according to consumption practice. Moreover, Guttman effect in principal component analysis uncovered a unique phenomenon which showed that participants (consumer vs. non consumer) were inclined to act differently only in the case of polemical issues when they perceived the investigator as a consumer vs. non consumer. Indeed, in the case of hegemonic beliefs they were inclined to act in the same way and their answers were not influenced by the status of the investigator. Results are discussed around the question of the links between social representations and social identity.

Differential temporal dynamics during visual imagery and perception.

PubMed

Dijkstra, Nadine; Mostert, Pim; Lange, Floris P de; Bosch, Sander; van Gerven, Marcel Aj

2018-05-29

Visual perception and imagery rely on similar representations in the visual cortex. During perception, visual activity is characterized by distinct processing stages, but the temporal dynamics underlying imagery remain unclear. Here, we investigated the dynamics of visual imagery in human participants using magnetoencephalography. Firstly, we show that, compared to perception, imagery decoding becomes significant later and representations at the start of imagery already overlap with later time points. This suggests that during imagery, the entire visual representation is activated at once or that there are large differences in the timing of imagery between trials. Secondly, we found consistent overlap between imagery and perceptual processing around 160 ms and from 300 ms after stimulus onset. This indicates that the N170 gets reactivated during imagery and that imagery does not rely on early perceptual representations. Together, these results provide important insights for our understanding of the neural mechanisms of visual imagery. © 2018, Dijkstra et al.

Molecular Mechanisms in Perirhinal Cortex Selectively Necessary for Discrimination of Overlapping Memories, but Independent of Memory Persistence

PubMed Central

Miranda, Magdalena; Kent, Brianne A.; Weisstaub, Noelia V.

2017-01-01

Abstract Successful memory involves not only remembering over time but also keeping memories distinct. The ability to separate similar experiences into distinct memories is a main feature of episodic memory. Discrimination of overlapping representations has been investigated in the dentate gyrus of the hippocampus (DG), but little is known about this process in other regions such as the perirhinal cortex (Prh). We found in male rats that perirhinal brain-derived neurotrophic factor (BDNF) is required for separable storage of overlapping, but not distinct, object representations, which is identical to its role in the DG for spatial representations. Also, activity-regulated cytoskeletal-associated protein (Arc) is required for disambiguation of object memories, as measured by infusion of antisense oligonucleotides. This is the first time Arc has been implicated in the discrimination of objects with overlapping features. Although molecular mechanisms for object memory have been shown previously in Prh, these have been dependent on delay, suggesting a role specifically in memory duration. BDNF and Arc involvement were independent of delay—the same demand for memory persistence was present in all conditions—but only when discrimination of similar objects was required were these mechanisms recruited and necessary. Finally, we show that BDNF and Arc participate in the same pathway during consolidation of overlapping object memories. We provide novel evidence regarding the proteins involved in disambiguation of object memories outside the DG and suggest that, despite the anatomical differences, similar mechanisms underlie this process in the DG and Prh that are engaged depending on the similarity of the stimuli. PMID:29085903

Genetic basis of mitochondrial sorting in cucumber

USDA-ARS?s Scientific Manuscript database

Regeneration of cucumber from cell cultures produces plants with distinct mosaic (MSC) phenotypes, misshapen cotyledons and leaves, reduced fertility, and low seed germination. The MSC phenotypes are paternally transmitted and associated with deletions or under-representations of specific regions of...

Genetic basis of mitochondrial sorting in cucumber

USDA-ARS?s Scientific Manuscript database

Regeneration of cucumber (Cucumis sativus) from cell cultures produces plants with distinct mosaic (MSC) phenotypes, misshapen cotyledons and leaves, reduced fertility, and low seed germination. The MSC phenotypes are paternally transmitted and associated with deletions or under-representations of s...

Time representations in social science

PubMed Central

Schulz, Yvan

2012-01-01

Time has long been a major topic of study in social science, as in other sciences or in philosophy. Social scientists have tended to focus on collective representations of time, and on the ways in which these representations shape our everyday experiences. This contribution addresses work from such disciplines as anthropology, sociology and history. It focuses on several of the main theories that have preoccupied specialists in social science, such as the alleged “acceleration” of life and overgrowth of the present in contemporary Western societies, or the distinction between so-called linear and circular conceptions of time. The presentation of these theories is accompanied by some of the critiques they have provoked, in order to enable the reader to form her or his own opinion of them. PMID:23393420

Time representations in social science.

PubMed

Schulz, Yvan

2012-12-01

Time has long been a major topic of study in social science, as in other sciences or in philosophy. Social scientists have tended to focus on collective representations of time, and on the ways in which these representations shape our everyday experiences. This contribution addresses work from such disciplines as anthropology, sociology and history. It focuses on several of the main theories that have preoccupied specialists in social science, such as the alleged "acceleration" of life and overgrowth of the present in contemporary Western societies, or the distinction between so-called linear and circular conceptions of time. The presentation of these theories is accompanied by some of the critiques they have provoked, in order to enable the reader to form her or his own opinion of them.

Distinct Laterality in Forelimb-Movement Representations of Rat Primary and Secondary Motor Cortical Neurons with Intratelencephalic and Pyramidal Tract Projections.

PubMed

Soma, Shogo; Saiki, Akiko; Yoshida, Junichi; Ríos, Alain; Kawabata, Masanori; Sakai, Yutaka; Isomura, Yoshikazu

2017-11-08

Two distinct motor areas, the primary and secondary motor cortices (M1 and M2), play crucial roles in voluntary movement in rodents. The aim of this study was to characterize the laterality in motor cortical representations of right and left forelimb movements. To achieve this goal, we developed a novel behavioral task, the Right-Left Pedal task, in which a head-restrained male rat manipulates a right or left pedal with the corresponding forelimb. This task enabled us to monitor independent movements of both forelimbs with high spatiotemporal resolution. We observed phasic movement-related neuronal activity (Go-type) and tonic hold-related activity (Hold-type) in isolated unilateral movements. In both M1 and M2, Go-type neurons exhibited bias toward contralateral preference, whereas Hold-type neurons exhibited no bias. The contralateral bias was weaker in M2 than M1. Moreover, we differentiated between intratelencephalic (IT) and pyramidal tract (PT) neurons using optogenetically evoked spike collision in rats expressing channelrhodopsin-2. Even in identified PT and IT neurons, Hold-type neurons exhibited no lateral bias. Go-type PT neurons exhibited bias toward contralateral preference, whereas IT neurons exhibited no bias. Our findings suggest a different laterality of movement representations of M1 and M2, in each of which IT neurons are involved in cooperation of bilateral movements, whereas PT neurons control contralateral movements. SIGNIFICANCE STATEMENT In rodents, the primary and secondary motor cortices (M1 and M2) are involved in voluntary movements via distinct projection neurons: intratelencephalic (IT) neurons and pyramidal tract (PT) neurons. However, it remains unclear whether the two motor cortices (M1 vs M2) and the two classes of projection neurons (IT vs PT) have different laterality of movement representations. We optogenetically identified these neurons and analyzed their functional activity using a novel behavioral task to monitor movements of the right and left forelimbs separately. We found that contralateral bias was reduced in M2 relative to M1, and in IT relative to PT neurons. Our findings suggest that the motor information processing that controls forelimb movement is coordinated by a distinct cell population. Copyright © 2017 the authors 0270-6474/17/3710904-13$15.00/0.

Vecteurs Singuliers des Theories des Champs Conformes Minimales

NASA Astrophysics Data System (ADS)

Benoit, Louis

En 1984 Belavin, Polyakov et Zamolodchikov revolutionnent la theorie des champs en explicitant une nouvelle gamme de theories, les theories quantiques des champs bidimensionnelles invariantes sous les transformations conformes. L'algebre des transformations conformes de l'espace-temps presente une caracteristique remarquable: en deux dimensions elle possede un nombre infini de generateurs. Cette propriete impose de telles conditions aux fonctions de correlations qu'il est possible de les evaluer sans aucune approximation. Les champs des theories conformes appartiennent a des representations de plus haut poids de l'algebre de Virasoro, une extension centrale de l'algebre conforme du plan. Ces representations sont etiquetees par h, le poids conforme de leur vecteur de plus haut poids, et par la charge centrale c, le facteur de l'extension centrale, commune a toutes les representations d'une meme theorie. Les theories conformes minimales sont constituees d'un nombre fini de representations. Parmi celles-ci se trouvent des theories unitaires dont les representation forment la serie discrete de l'algebre de Virasoro; leur poids h a la forme h_{p,q}(m)=[ (p(m+1) -qm)^2-1] (4m(m+1)), ou p,q et m sont des entiers positifs et p+q<= m+1. L'entier m parametrise la charge centrale: c(m)=1 -{6over m(m+1)} avec n>= 2. Ces representations possedent un sous-espace invariant engendre par deux sous-representations avec h_1=h_{p,q} + pq et h_2=h_{p,q} + (m-p)(m+1-q) dont chacun des vecteurs de plus haut poids portent le nom de vecteur singulier et sont notes respectivement |Psi _{p,q}> et |Psi_{m-p,m+1-q}>. . Les theories super-conformes sont une version super-symetrique des theories conformes. Leurs champs appartiennent a des representation de plus haut poids de l'algebre de Neveu-Schwarz, une des deux extensions super -symetriques de l'algebre de Virasoro. Les theories super -conformes minimales possedent la meme structure que les theories conformes minimales. Les representations sont elements de la serie h_{p,q}= [ (p(m+2)-qm)^2-4] /(8m(m+2)) ou p,q et m sont des entiers positifs, p et q etant de meme parite, et p+q<= m+2. La charge centrale est donnee par c(m)={3over 2}-{12over m(m+2)} avec m >= 2. Les vecteurs singuliers | Psi_{p,q}> et |Psi_{m-p,m+2-q} > sont respectivement de poids h _{p,q}+pq/2 et h_ {p,q}+(m-p)(m+2-q)/2.. Les vecteurs singuliers ont une norme nulle et on doit les eliminer des representations pour que celles -ci soient unitaires. Cette elimination engendrent des equations (super-)differentielles qui dependent directement de la forme explicite des vecteurs singuliers et auxquelles doivent obeir les fonctions de correlations de la theorie. Ainsi la connaissance de ces vecteurs singuliers est intimement reliee au calcul des fonctions de correlation. Les equations definissant les vecteurs singuliers forment un systeme lineaire surdetermine dont le nombre d'equations est de l'ordre de N(pq), le nombre de partitions de l'entier pq. Puisque les vecteurs singuliers jouent un role capital en theorie conforme, il est naturel de chercher des formes explicites pour les vecteurs (ou pour des familles infinies de ceux -ci). Nous donnons ici la forme explicite pour la famille infinie de vecteurs singuliers ayant un de ses indices egal a 1, pour les algebres de Virasoro et de Neveu-Schwarz. Depuis ces decouvertes, d'autres techniques de construction des vecteurs singuliers ont ete developpees, dont celle de Bauer, Di Francesco, Itzykson et Zuber pour l'algebre de Virasoro qui reproduit directement l'expression explicite des vecteurs singuliers |Psi _{1,q}> et |Psi_{p,1}>. Ils ont utilise l'algebre des produits d'operateurs et la fusion entre representations irreductibles pour engendrer des relations de recurence produisant les vecteurs singuliers. Dans le dernier chapitre de cette these nous adaptons cet algorithme a la construction des vecteurs singuliers de l'algebre de Neveu-Schwarz.

Update on "What" and "Where" in Spatial Language: A New Division of Labor for Spatial Terms.

PubMed

Landau, Barbara

2017-03-01

In this article, I revisit Landau and Jackendoff's () paper, "What and where in spatial language and spatial cognition," proposing a friendly amendment and reformulation. The original paper emphasized the distinct geometries that are engaged when objects are represented as members of object kinds (named by count nouns), versus when they are represented as figure and ground in spatial expressions (i.e., play the role of arguments of spatial prepositions). We provided empirical and theoretical arguments for the link between these distinct representations in spatial language and their accompanying nonlinguistic neural representations, emphasizing the "what" and "where" systems of the visual system. In the present paper, I propose a second division of labor between two classes of spatial prepositions in English that appear to be quite distinct. One class includes prepositions such as in and on, whose core meanings engage force-dynamic, functional relationships between objects, with geometry only a marginal player. The second class includes prepositions such as above/below and right/left, whose core meanings engage geometry, with force-dynamic relationships a passing or irrelevant variable. The insight that objects' force-dynamic relationships matter to spatial terms' uses is not new; but thinking of these terms as a distinct set within spatial language has theoretical and empirical consequences that are new. I propose three such consequences, rooted in the fact that geometric knowledge is highly constrained and early-emerging in life, while force-dynamic knowledge of objects and their interactions is relatively unconstrained and needs to be learned piecemeal over a lengthy timeline. First, the two classes will engage different learning problems, with different developmental trajectories for both first and second language learners; second, the classes will naturally lead to different degrees of cross-linguistic variation; and third, they may be rooted in different neural representations. Copyright © 2016 Cognitive Science Society, Inc.

Knowledge of the human body: a distinct semantic domain.

PubMed

Coslett, H Branch; Saffran, Eleanor M; Schwoebel, John

2002-08-13

Patients with selective deficits in the naming and comprehension of animals, plants, and artifacts have been reported. These descriptions of specific semantic category deficits have contributed substantially to the understanding of the architecture of semantic representations. This study sought to further understanding of the organization of the semantic system by demonstrating that another semantic category, knowledge of the human body, may be selectively preserved. The performance of a patient with semantic dementia was compared with the performance of healthy controls on a variety of tasks assessing distinct types of body representations, including the body schema, body image, and body structural description. Despite substantial deficits on tasks involving language and knowledge of the world generally, the patient performed normally on all tests of body knowledge except body part naming; even in this naming task, however, her performance with body parts was significantly better than on artifacts. The demonstration that body knowledge may be preserved despite substantial semantic deficits involving other types of semantic information argues that body knowledge is a distinct and dissociable semantic category. These data are interpreted as support for a model of semantics that proposes that knowledge is distributed across different cortical regions reflecting the manner in which the information was acquired.

Using fuzzy-trace theory to understand and improve health judgments, decisions, and behaviors: A literature review.

PubMed

Blalock, Susan J; Reyna, Valerie F

2016-08-01

Fuzzy-trace theory is a dual-process model of memory, reasoning, judgment, and decision making that contrasts with traditional expectancy-value approaches. We review the literature applying fuzzy-trace theory to health with 3 aims: evaluating whether the theory's basic distinctions have been validated empirically in the domain of health; determining whether these distinctions are useful in assessing, explaining, and predicting health-related psychological processes; and determining whether the theory can be used to improve health judgments, decisions, or behaviors, especially compared to other approaches. We conducted a literature review using PubMed, PsycINFO, and Web of Science to identify empirical peer-reviewed papers that applied fuzzy-trace theory, or central constructs of the theory, to investigate health judgments, decisions, or behaviors. Seventy nine studies (updated total is 94 studies; see Supplemental materials) were identified, over half published since 2012, spanning a wide variety of conditions and populations. Study findings supported the prediction that verbatim and gist representations are distinct constructs that can be retrieved independently using different cues. Although gist-based reasoning was usually associated with improved judgment and decision making, 4 sources of bias that can impair gist reasoning were identified. Finally, promising findings were reported from intervention studies that used fuzzy-trace theory to improve decision making and decrease unhealthy risk taking. Despite large gaps in the literature, most studies supported all 3 aims. By focusing on basic psychological processes that underlie judgment and decision making, fuzzy-trace theory provides insights into how individuals make decisions involving health risks and suggests innovative intervention approaches to improve health outcomes. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Water exchange and pressure transfer between conduits and matrix and their influence on hydrodynamics of two karst aquifers with sinking streams

NASA Astrophysics Data System (ADS)

Bailly-Comte, Vincent; Martin, Jonathan B.; Jourde, Hervé; Screaton, Elizabeth J.; Pistre, Séverin; Langston, Abigail

2010-05-01

SummaryKarst aquifers are heterogeneous media where conduits usually drain water from lower permeability volumes (matrix and fractures). For more than a century, various approaches have used flood recession curves, which integrate all hydrodynamic processes in a karst aquifer, to infer physical properties of the movement and storage of groundwater. These investigations typically only consider flow to the conduits and thus have lacked quantitative observations of how pressure transfer and water exchange between matrix and conduit during flooding could influence recession curves. We present analyses of simultaneous discharge and water level time series of two distinctly different karst systems, one with low porosity and permeability matrix rocks in southern France, and one with high porosity and permeability matrix rocks in north-central Florida (USA). We apply simple mathematical models of flood recession using time series representations of recharge, storage, and discharge processes in the karst aquifer. We show that karst spring hydrographs can be interpreted according to pressure transfer between two distinct components of the aquifer, conduit and matrix porosity, which induce two distinct responses at the spring. Water exchange between conduits and matrix porosity successively control the flow regime at the spring. This exchange is governed by hydraulic head differences between conduits and matrix, head gradients within conduits, and the contrast of permeability between conduits and matrix. These observations have consequences for physical interpretations of recession curves and modeling of karst spring flows, particularly for the relative magnitudes of base flow and quick flow from karst springs. Finally, these results suggest that similar analyses of recession curves can be applied to karst aquifers with distinct physical characteristics utilizing well and spring hydrograph data, but information must be known about the hydrodynamics and physical properties of the aquifer before the results can be correctly interpreted.

Is the difference between right and left ATLs due to the distinction between general and social cognition or between verbal and non-verbal representations?

PubMed

Gainotti, Guido

2015-04-01

The present review aimed to check two proposals alternative to the original version of the 'semantic hub' hypothesis, based on semantic dementia (SD) data, which assumed that left and right anterior temporal lobes (ATLs) store in a unitary, amodal format all kinds of semantic representations. The first alternative proposal is that the right ATL might subsume non-verbal representations and the left ATL lexical-semantic representations and that only in the advanced stages of SD, when atrophy affects the ATLs bilaterally, the semantic impairment becomes 'multi-modal'. The second alternative suggestion is that right and left ATLs might underlie two different domains of knowledge, because general conceptual knowledge might be supported by the left ATL, and social cognition by the right ATL. Results of the review substantially support the first proposal, showing that the right ATL subsumes non-verbal representations and the left ATL lexical-semantic representations. They are less conclusive about the second suggestion, because the right ATL seems to play a more important role in behavioral and emotional functions than in higher level social cognition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mental Representation and Mental Practice: Experimental Investigation on the Functional Links between Motor Memory and Motor Imagery

PubMed Central

Frank, Cornelia; Land, William M.; Popp, Carmen; Schack, Thomas

2014-01-01

Recent research on mental representation of complex action has revealed distinct differences in the structure of representational frameworks between experts and novices. More recently, research on the development of mental representation structure has elicited functional changes in novices' representations as a result of practice. However, research investigating if and how mental practice adds to this adaptation process is lacking. In the present study, we examined the influence of mental practice (i.e., motor imagery rehearsal) on both putting performance and the development of one's representation of the golf putt during early skill acquisition. Novice golfers (N = 52) practiced the task of golf putting under one of four different practice conditions: mental, physical, mental-physical combined, and no practice. Participants were tested prior to and after a practice phase, as well as after a three day retention interval. Mental representation structures of the putt were measured, using the structural dimensional analysis of mental representation. This method provides psychometric data on the distances and groupings of basic action concepts in long-term memory. Additionally, putting accuracy and putting consistency were measured using two-dimensional error scores of each putt. Findings revealed significant performance improvements over the course of practice together with functional adaptations in mental representation structure. Interestingly, after three days of practice, the mental representations of participants who incorporated mental practice into their practice regime displayed representation structures that were more similar to a functional structure than did participants who did not incorporate mental practice. The findings of the present study suggest that mental practice promotes the cognitive adaptation process during motor learning, leading to more elaborate representations than physical practice only. PMID:24743576

Second Language Acquisition.

ERIC Educational Resources Information Center

McLaughlin, Barry; Harrington, Michael

1989-01-01

A distinction is drawn between representational and processing models of second-language acquisition. The first approach is derived primarily from linguistics, the second from psychology. Both fields, it is argued, need to collaborate more fully, overcoming disciplinary narrowness in order to achieve more fruitful research. (GLR)

The Origin of Word-related Motor Activity

PubMed Central

Papeo, Liuba; Lingnau, Angelika; Agosta, Sara; Pascual-Leone, Alvaro; Battelli, Lorella; Caramazza, Alfonso

2015-01-01

Conceptual processing of verbs consistently recruits the left posterior middle temporal gyrus (lpMTG). The left precentral motor cortex also responds to verbs, with higher activity for action than nonaction verbs. The early timing of this effect has suggested that motor features of words' meaning are accessed directly, bypassing access to conceptual representations in lpMTG. An alternative hypothesis is that the retrieval of conceptual representations in lpMTG is necessary to drive more specific, motor-related representations in the precentral gyrus. To test these hypotheses, we first showed that repetitive transcranial magnetic stimulation (rTMS) applied to the verb-preferring lpMTG site selectively impoverished the semantic processing of verbs. In a second experiment, rTMS perturbation of lpMTG, relative to no stimulation (no-rTMS), eliminated the action–nonaction verb distinction in motor activity, as indexed by motor-evoked potentials induced in peripheral muscles with single-pulse TMS over the left primary motor cortex. rTMS pertubation of an occipital control site, relative to no-rTMS, did not affect the action–nonaction verb distinction in motor activity, but the verb contrast did not differ reliably from the lpMTG effect. The results show that lpMTG carries core semantic information necessary to drive the activation of specific (motor) features in the precentral gyrus. PMID:24421174

Quantitative autoradiographic analysis of muscarinic receptor subtypes and their role in representational memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Messer, W.S.

1986-01-01

Autoradiographic techniques were used to examine the distribution of muscarinic receptors in rat brain slices. Agonist and selective antagonist binding were examined by measuring the ability for unlabeled ligands to inhibit (/sup 3/H)-1-QNB labeling of muscarinic receptors. The distribution of high affinity pirenzepine binding sites (M/sub 1/ subtype) was distinct from the distribution of high affinity carbamylcholine sites, which corresponded to the M/sub 2/ subtype. In a separate assay, the binding profile for pirenzepine was shown to differ from the profile for scopolamine, a classical muscarinic antagonist. Muscarinic antagonists, when injected into the Hippocampus, impaired performance of a representational memorymore » task. Pirenzepine, the M/sub 1/ selective antagonist, produced representational memory deficits. Scopolamine, a less selective muscarinic antagonist, caused increases in running times in some animals which prevented a definitive interpretation of the nature of the impairment. Pirenzepine displayed a higher affinity for the hippocampus and was more effective in producing a selective impairment of representational memory than scopolamine. The data indicated that cholinergic activity in the hippocampus was necessary for representation memory function.« less

User-based representation of time-resolved multimodal public transportation networks.

PubMed

Alessandretti, Laura; Karsai, Márton; Gauvin, Laetitia

2016-07-01

Multimodal transportation systems, with several coexisting services like bus, tram and metro, can be represented as time-resolved multilayer networks where the different transportation modes connecting the same set of nodes are associated with distinct network layers. Their quantitative description became possible recently due to openly accessible datasets describing the geo-localized transportation dynamics of large urban areas. Advancements call for novel analytics, which combines earlier established methods and exploits the inherent complexity of the data. Here, we provide a novel user-based representation of public transportation systems, which combines representations, accounting for the presence of multiple lines and reducing the effect of spatial embeddedness, while considering the total travel time, its variability across the schedule, and taking into account the number of transfers necessary. After the adjustment of earlier techniques to the novel representation framework, we analyse the public transportation systems of several French municipal areas and identify hidden patterns of privileged connections. Furthermore, we study their efficiency as compared to the commuting flow. The proposed representation could help to enhance resilience of local transportation systems to provide better design policies for future developments.

User-based representation of time-resolved multimodal public transportation networks

PubMed Central

Alessandretti, Laura; Gauvin, Laetitia

2016-01-01

Multimodal transportation systems, with several coexisting services like bus, tram and metro, can be represented as time-resolved multilayer networks where the different transportation modes connecting the same set of nodes are associated with distinct network layers. Their quantitative description became possible recently due to openly accessible datasets describing the geo-localized transportation dynamics of large urban areas. Advancements call for novel analytics, which combines earlier established methods and exploits the inherent complexity of the data. Here, we provide a novel user-based representation of public transportation systems, which combines representations, accounting for the presence of multiple lines and reducing the effect of spatial embeddedness, while considering the total travel time, its variability across the schedule, and taking into account the number of transfers necessary. After the adjustment of earlier techniques to the novel representation framework, we analyse the public transportation systems of several French municipal areas and identify hidden patterns of privileged connections. Furthermore, we study their efficiency as compared to the commuting flow. The proposed representation could help to enhance resilience of local transportation systems to provide better design policies for future developments. PMID:27493773

Discours oraux--discours ecrits: quelles relations? Actes du 4eme colloque d'orthophoine/logopedie (Neuchatel, 3-4 octobre, 1996) (Oral Discourse--Written Discourse: What Is the Relationship? Proceedings of the Colloquium on Speech Therapy (4th, Neuchatel, Switzerland, October 3-4, 1996).

ERIC Educational Resources Information Center

Py, Bernard, Ed.

1996-01-01

Research papers on the relationship between oral and written language include: "Une distinction bien fragile: oral/ecrit" ("A Fragile Distinction: Oral/Written") (Francoise Gadet); "Oral et ecrit dans les representations des enseignants et dans les pratiques quotidiennes de la classe de francais" ("Oral and Written Language in Teachers'…

The Role of Familiarity for Representations in Norm-Based Face Space

PubMed Central

Faerber, Stella J.; Kaufmann, Jürgen M.; Leder, Helmut; Martin, Eva Maria; Schweinberger, Stefan R.

2016-01-01

According to the norm-based version of the multidimensional face space model (nMDFS, Valentine, 1991), any given face and its corresponding anti-face (which deviates from the norm in exactly opposite direction as the original face) should be equidistant to a hypothetical prototype face (norm), such that by definition face and anti-face should bear the same level of perceived typicality. However, it has been argued that familiarity affects perceived typicality and that representations of familiar faces are qualitatively different (e.g., more robust and image-independent) from those for unfamiliar faces. Here we investigated the role of face familiarity for rated typicality, using two frequently used operationalisations of typicality (deviation-based: DEV), and distinctiveness (face in the crowd: FITC) for faces of celebrities and their corresponding anti-faces. We further assessed attractiveness, likeability and trustworthiness ratings of the stimuli, which are potentially related to typicality. For unfamiliar faces and their corresponding anti-faces, in line with the predictions of the nMDFS, our results demonstrate comparable levels of perceived typicality (DEV). In contrast, familiar faces were perceived much less typical than their anti-faces. Furthermore, familiar faces were rated higher than their anti-faces in distinctiveness, attractiveness, likability and trustworthiness. These findings suggest that familiarity strongly affects the distribution of facial representations in norm-based face space. Overall, our study suggests (1) that familiarity needs to be considered in studies of mental representations of faces, and (2) that familiarity, general distance-to-norm and more specific vector directions in face space make different and interactive contributions to different types of facial evaluations. PMID:27168323

The Role of Familiarity for Representations in Norm-Based Face Space.

PubMed

Faerber, Stella J; Kaufmann, Jürgen M; Leder, Helmut; Martin, Eva Maria; Schweinberger, Stefan R

2016-01-01

According to the norm-based version of the multidimensional face space model (nMDFS, Valentine, 1991), any given face and its corresponding anti-face (which deviates from the norm in exactly opposite direction as the original face) should be equidistant to a hypothetical prototype face (norm), such that by definition face and anti-face should bear the same level of perceived typicality. However, it has been argued that familiarity affects perceived typicality and that representations of familiar faces are qualitatively different (e.g., more robust and image-independent) from those for unfamiliar faces. Here we investigated the role of face familiarity for rated typicality, using two frequently used operationalisations of typicality (deviation-based: DEV), and distinctiveness (face in the crowd: FITC) for faces of celebrities and their corresponding anti-faces. We further assessed attractiveness, likeability and trustworthiness ratings of the stimuli, which are potentially related to typicality. For unfamiliar faces and their corresponding anti-faces, in line with the predictions of the nMDFS, our results demonstrate comparable levels of perceived typicality (DEV). In contrast, familiar faces were perceived much less typical than their anti-faces. Furthermore, familiar faces were rated higher than their anti-faces in distinctiveness, attractiveness, likability and trustworthiness. These findings suggest that familiarity strongly affects the distribution of facial representations in norm-based face space. Overall, our study suggests (1) that familiarity needs to be considered in studies of mental representations of faces, and (2) that familiarity, general distance-to-norm and more specific vector directions in face space make different and interactive contributions to different types of facial evaluations.

Happiness is pleasant, or is it? Implicit representations of affect valence are associated with contrahedonic motivation and mixed affect in daily life.

PubMed

Riediger, Michaela; Wrzus, Cornelia; Wagner, Gert G

2014-10-01

People typically want to feel good. At times, however, they seek to maintain or enhance negative affect or to dampen positive affect. The prevalence of such contrahedonic motivation has been related to simultaneous experiences of positive and negative (i.e., mixed) affect. We investigated the role that implicit mental representations of affect valence may play in this regard in a study with N = 400 participants aged 11-88 years. Results demonstrated the age-fairness and reliability of the affect-valence Implicit Association Test, a newly developed implicit measure of interindividual differences in mental representations of affect valence. The older participants were, the more distinctively they implicitly associated happiness with pleasantness and/or unhappiness with unpleasantness. Participants furthermore carried mobile phones as assessment instruments with them for 3 weeks while pursuing their daily routines. The phones prompted participants on average 54 times to report their momentary affective experience and affect-regulation motivation. Contrahedonic motivation and mixed affect were most prevalent among adolescents and least prevalent among older adults, and thus showed a similar pattern of age differences as the affect-valence Implicit Association Test. Furthermore, the more distinctive participants' implicit associations of happiness with pleasantness, and/or unhappiness with unpleasantness, the less likely participants were to report contrahedonic motivation and mixed affect in their daily lives. These findings contribute to a refined understanding of the mixed-affect perspective on contrahedonic motivation by demonstrating the respective role of implicit affect-valence representations. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Arithmetic Memory Is Modality Specific.

PubMed

Myers, Timothy; Szücs, Dénes

2015-01-01

In regards to numerical cognition and working memory, it is an open question as to whether numbers are stored into and retrieved from a central abstract representation or from separate notation-specific representations. This study seeks to help answer this by utilizing the numeral modality effect (NME) in three experiments to explore how numbers are processed by the human brain. The participants were presented with numbers (1-9) as either Arabic digits or written number words (Arabic digits and dot matrices in Experiment 2) at the first (S1) and second (S2) stimuli. The participant's task was to add the first two stimuli together and verify whether the answer (S3), presented simultaneously with S2, was correct. We hypothesized that if reaction time (RT) at S2/S3 depends on the modality of S1 then numbers are retrieved from modality specific memory stores. Indeed, RT depended on the modality of S1 whenever S2 was an Arabic digit which argues against the concept of numbers being stored and retrieved from a central, abstract representation.

Arithmetic Memory Is Modality Specific

PubMed Central

Myers, Timothy; Szücs, Dénes

2015-01-01

In regards to numerical cognition and working memory, it is an open question as to whether numbers are stored into and retrieved from a central abstract representation or from separate notation-specific representations. This study seeks to help answer this by utilizing the numeral modality effect (NME) in three experiments to explore how numbers are processed by the human brain. The participants were presented with numbers (1–9) as either Arabic digits or written number words (Arabic digits and dot matrices in Experiment 2) at the first (S1) and second (S2) stimuli. The participant’s task was to add the first two stimuli together and verify whether the answer (S3), presented simultaneously with S2, was correct. We hypothesized that if reaction time (RT) at S2/S3 depends on the modality of S1 then numbers are retrieved from modality specific memory stores. Indeed, RT depended on the modality of S1 whenever S2 was an Arabic digit which argues against the concept of numbers being stored and retrieved from a central, abstract representation. PMID:26716692

Baryon spectrum of SU(4) composite Higgs theory with two distinct fermion representations

NASA Astrophysics Data System (ADS)

Ayyar, Venkitesh; DeGrand, Thomas; Hackett, Daniel C.; Jay, William I.; Neil, Ethan T.; Shamir, Yigal; Svetitsky, Benjamin

2018-06-01

We use lattice simulations to compute the baryon spectrum of SU(4) lattice gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations simultaneously. This model is closely related to a composite Higgs model in which the chimera baryon made up of fermions from both representations plays the role of a composite top-quark partner. The dependence of the baryon masses on each underlying fermion mass is found to be generally consistent with a quark-model description and large-Nc scaling. We combine our numerical results with experimental bounds on the scale of the new strong sector to estimate a lower bound on the mass of the top-quark partner. We discuss some theoretical uncertainties associated with this estimate.

Similarity-based interference in a working memory numerical updating task: age-related differences between younger and older adults.

PubMed

Pelegrina, Santiago; Borella, Erika; Carretti, Barbara; Lechuga, M Teresa

2012-01-01

Similarity among representations held simultaneously in working memory (WM) is a factor which increases interference and hinders performance. The aim of the current study was to investigate age-related differences between younger and older adults in a working memory numerical updating task, in which the similarity between information held in WM was manipulated. Results showed a higher susceptibility of older adults to similarity-based interference when accuracy, and not response times, was considered. It was concluded that older adults' WM difficulties appear to be due to the availability of stored information, which, in turn, might be related to the ability to generate distinctive representations and to the process of binding such representations to their context when similar information has to be processed in WM.

Serotonin and decision making processes.

PubMed

Homberg, Judith R

2012-01-01

Serotonin (5-HT) is an important player in decision making. Serotonergic antidepressant, anxiolytic and antipsychotic drugs are extensively used in the treatment of neuropsychiatric disorders characterized by impaired decision making, and exert both beneficial and harmful effects in patients. Detailed insight into the serotonergic mechanisms underlying decision making is needed to strengthen the first and weaken the latter. Although much remains to be done to achieve this, accumulating studies begin to deliver a coherent view. Thus, high central 5-HT levels are generally associated with improved reversal learning, improved attentional set shifting, decreased delay discounting, and increased response inhibition, but a failure to use outcome representations. Based on 5-HT's evolutionary role, I hypothesize that 5-HT integrates expected, or changes in, relevant sensory and emotional internal/external information, leading to vigilance behaviour affecting various decision making processes. 5-HT receptor subtypes play distinctive roles in decision making. 5-HT(2A) agonists and 5-HT2c antagonists decrease compulsivity, whereas 5-HT(2A) antagonists and 5-HT(2C) agonists decrease impulsivity. 5-HT(6) antagonists univocally affect decision making processes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Dissociating interference-control processes between memory and response.

PubMed

Bissett, Patrick G; Nee, Derek Evan; Jonides, John

2009-09-01

The ability to mitigate interference is of central importance to cognition. Previous research has provided conflicting accounts about whether operations that resolve interference are singular in character or form a family of functions. Here, the authors examined the relationship between interference-resolution processes acting on working memory representations versus responses. The authors combined multiple forms of interference into a single paradigm by merging a directed-forgetting task, which induces proactive interference, with a stop-signal task, which taps response inhibition processes. The results demonstrated that proactive interference and response inhibition produced distinct behavioral signatures that did not interact. By contrast, combining two different measures of response inhibition by merging a go/no-go task variant and a stop signal produced overadditive behavioral interference, demonstrating that different forms of response inhibition tap the same processes. However, not all forms of response conflict interacted, suggesting that inhibition-related functions acting on response selection are dissociable from those acting on response inhibition. These results suggest that inhibition-related functions for memory and responses are dissociable. (c) 2009 APA, all rights reserved.

The logical primitives of thought: Empirical foundations for compositional cognitive models.

PubMed

Piantadosi, Steven T; Tenenbaum, Joshua B; Goodman, Noah D

2016-07-01

The notion of a compositional language of thought (LOT) has been central in computational accounts of cognition from earliest attempts (Boole, 1854; Fodor, 1975) to the present day (Feldman, 2000; Penn, Holyoak, & Povinelli, 2008; Fodor, 2008; Kemp, 2012; Goodman, Tenenbaum, & Gerstenberg, 2015). Recent modeling work shows how statistical inferences over compositionally structured hypothesis spaces might explain learning and development across a variety of domains. However, the primitive components of such representations are typically assumed a priori by modelers and theoreticians rather than determined empirically. We show how different sets of LOT primitives, embedded in a psychologically realistic approximate Bayesian inference framework, systematically predict distinct learning curves in rule-based concept learning experiments. We use this feature of LOT models to design a set of large-scale concept learning experiments that can determine the most likely primitives for psychological concepts involving Boolean connectives and quantification. Subjects' inferences are most consistent with a rich (nonminimal) set of Boolean operations, including first-order, but not second-order, quantification. Our results more generally show how specific LOT theories can be distinguished empirically. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Short-term memory and long-term memory are still different.

PubMed

Norris, Dennis

2017-09-01

A commonly expressed view is that short-term memory (STM) is nothing more than activated long-term memory. If true, this would overturn a central tenet of cognitive psychology-the idea that there are functionally and neurobiologically distinct short- and long-term stores. Here I present an updated case for a separation between short- and long-term stores, focusing on the computational demands placed on any STM system. STM must support memory for previously unencountered information, the storage of multiple tokens of the same type, and variable binding. None of these can be achieved simply by activating long-term memory. For example, even a simple sequence of digits such as "1, 3, 1" where there are 2 tokens of the digit "1" cannot be stored in the correct order simply by activating the representations of the digits "1" and "3" in LTM. I also review recent neuroimaging data that has been presented as evidence that STM is activated LTM and show that these data are exactly what one would expect to see based on a conventional 2-store view. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Short-Term Memory and Long-Term Memory are Still Different

PubMed Central

2017-01-01

A commonly expressed view is that short-term memory (STM) is nothing more than activated long-term memory. If true, this would overturn a central tenet of cognitive psychology—the idea that there are functionally and neurobiologically distinct short- and long-term stores. Here I present an updated case for a separation between short- and long-term stores, focusing on the computational demands placed on any STM system. STM must support memory for previously unencountered information, the storage of multiple tokens of the same type, and variable binding. None of these can be achieved simply by activating long-term memory. For example, even a simple sequence of digits such as “1, 3, 1” where there are 2 tokens of the digit “1” cannot be stored in the correct order simply by activating the representations of the digits “1” and “3” in LTM. I also review recent neuroimaging data that has been presented as evidence that STM is activated LTM and show that these data are exactly what one would expect to see based on a conventional 2-store view. PMID:28530428

Prototypical Concepts and Misconceptions of Plate Tectonic Boundaries

NASA Astrophysics Data System (ADS)

Sibley, D. F.; Patino, L. C.

2003-12-01

Students of geology encounter many prototypical/exemplar concepts* that include representative, but not necessarily defining, features and characteristics. This study of students' prototypical representations of plate tectonic boundaries indicates that their representations are rich sources of information about their misconceptions about plate tectonics. After lectures in plate tectonics and mountain building, 353 students in a general education geology class were asked to draw a continent-continent convergent boundary. For this study, a correct answer is defined as having the major features in correct proportions as depicted in the plate boundary diagrams on the USGS web. Fifty-two percent of the drawings were either incorrect or incomplete such that they could not be interpreted. Only 48% were readily interpretable, and of these 22% drew the boundary correctly, showing a thickening of crust where two continents collide. Thirty-three percent drew the boundary showing concave slabs of continental crust as one might imagine two pieces of firm rubber pushed together on a rigid surface and 45% depicted mountains as one might imagine inverted ice cream cones on a rigid plank. Twenty-one senior class geology majors and graduate students were given the same assignment. Forty-eight percent rendered a correct drawing, whereas 38% drew the same ice cream cone on a plank type picture that 45% of the general education students drew. In a second class of 12 geology majors, only 1 student drew a cross section of a continent-ocean boundary similar to standard representation. Four of 12 drew mountains on the top of continental crust over a subduction zone but did not draw a compensating mass within the crust or lithosphere. Prototypical drawings provide more information about students' concepts than do most multiple-choice questions. For example, sixty-two percent of theses students who drew mountains similar to foam rubber pads pushed together on a desk or ice cream cones on a plank correctly answered a multiple-choice question that would appear to indicate a better understanding than the drawings reveal. Furthermore, 12 interviewed students made statements that could be interpreted to indicate that they understood the concept of mountain building at plate tectonic boundaries better than their drawings suggest. Incoherence of multiple-choice responses, verbal statements and drawings may be common in novice learners. If cognitive scientists are correct in their model of multiple types of mental representations for the same term, then the fact that novices may hold inconsistent representations is not surprising. The fact that students at various academic levels draw very similar prototypes that are incorrect is evidence that students have distinct and persistent prototype misconceptions. * Cognitive scientists define a prototypical/exemplar concept as a mental representation of the best examples or central tendencies of a term.

Reading Comprehension in Children with ADHD: Cognitive Underpinnings of the Centrality Deficit

ERIC Educational Resources Information Center

Miller, Amanda C.; Keenan, Janice M.; Betjemann, Rebecca S.; Willcutt, Erik G.; Pennington, Bruce F.; Olson, Richard K.

2013-01-01

We examined reading comprehension in children with ADHD by assessing their ability to build a coherent mental representation that allows them to recall central and peripheral information. We compared children with ADHD (mean age 9.78) to word reading-matched controls (mean age 9.89) on their ability to retell a passage. We found that even though…

Using Centrality of Concept Maps as a Measure of Problem Space States in Computer-Supported Collaborative Problem Solving

ERIC Educational Resources Information Center

Clariana, Roy B.; Engelmann, Tanja; Yu, Wu

2013-01-01

Problem solving likely involves at least two broad stages, problem space representation and then problem solution (Newell and Simon, Human problem solving, 1972). The metric centrality that Freeman ("Social Networks" 1:215-239, 1978) implemented in social network analysis is offered here as a potential measure of both. This development research…

When Children Are Water: Representation of Central American Migrant Children in Public Discourse and Implications for Educators

ERIC Educational Resources Information Center

Catalano, Theresa

2017-01-01

Since June, 2014 when the U.S. government began to document an increase in unaccompanied/separated children arriving in the United States from Central America, these children have become a frequent topic in media discourse. Because rhetoric about immigration issues have been shown to affect schooling of these children, the present article aims to…

Feature Statistics Modulate the Activation of Meaning during Spoken Word Processing

ERIC Educational Resources Information Center

Devereux, Barry J.; Taylor, Kirsten I.; Randall, Billi; Geertzen, Jeroen; Tyler, Lorraine K.

2016-01-01

Understanding spoken words involves a rapid mapping from speech to conceptual representations. One distributed feature-based conceptual account assumes that the statistical characteristics of concepts' features--the number of concepts they occur in ("distinctiveness/sharedness") and likelihood of co-occurrence ("correlational…

Explorations in Context Space: Words, Sentences, Discourse.

ERIC Educational Resources Information Center

Burgess, Curt; Livesay, Kay; Lund, Kevin

1998-01-01

Describes a computational model of high-dimensional context space: the Hyperspace Analog to Language (HAL). Shows that HAL provides sufficient information to make semantic, grammatical, and abstract distinctions. Demonstrates the cognitive compatibility of the representations with human processing; and introduces a new methodology that extracts…

Distinct contributions of functional and deep neural network features to representational similarity of scenes in human brain and behavior

PubMed Central

Greene, Michelle R; Baldassano, Christopher; Fei-Fei, Li; Beck, Diane M; Baker, Chris I

2018-01-01

Inherent correlations between visual and semantic features in real-world scenes make it difficult to determine how different scene properties contribute to neural representations. Here, we assessed the contributions of multiple properties to scene representation by partitioning the variance explained in human behavioral and brain measurements by three feature models whose inter-correlations were minimized a priori through stimulus preselection. Behavioral assessments of scene similarity reflected unique contributions from a functional feature model indicating potential actions in scenes as well as high-level visual features from a deep neural network (DNN). In contrast, similarity of cortical responses in scene-selective areas was uniquely explained by mid- and high-level DNN features only, while an object label model did not contribute uniquely to either domain. The striking dissociation between functional and DNN features in their contribution to behavioral and brain representations of scenes indicates that scene-selective cortex represents only a subset of behaviorally relevant scene information. PMID:29513219

Distinct contributions of functional and deep neural network features to representational similarity of scenes in human brain and behavior.

PubMed

Groen, Iris Ia; Greene, Michelle R; Baldassano, Christopher; Fei-Fei, Li; Beck, Diane M; Baker, Chris I

2018-03-07

Inherent correlations between visual and semantic features in real-world scenes make it difficult to determine how different scene properties contribute to neural representations. Here, we assessed the contributions of multiple properties to scene representation by partitioning the variance explained in human behavioral and brain measurements by three feature models whose inter-correlations were minimized a priori through stimulus preselection. Behavioral assessments of scene similarity reflected unique contributions from a functional feature model indicating potential actions in scenes as well as high-level visual features from a deep neural network (DNN). In contrast, similarity of cortical responses in scene-selective areas was uniquely explained by mid- and high-level DNN features only, while an object label model did not contribute uniquely to either domain. The striking dissociation between functional and DNN features in their contribution to behavioral and brain representations of scenes indicates that scene-selective cortex represents only a subset of behaviorally relevant scene information.

The cortical sensory representation of genitalia in women and men: a systematic review

PubMed Central

Cazala, Fadwa; Vienney, Nicolas; Stoléru, Serge

2015-01-01

Background Although genital sensations are an essential aspect of sexual behavior, the cortical somatosensory representation of genitalia in women and men remain poorly known and contradictory results have been reported. Objective To conduct a systematic review of studies based on electrophysiological and functional neuroimaging studies, with the aim to identify insights brought by modern methods since the early descriptions of the sensory homunculus in the primary somatosensory cortex (SI). Results The review supports the interpretation that there are two distinct representations of genital sensations in SI, one on the medial surface and the other on the lateral surface. In addition, the review suggests that the secondary somatosensory cortex and the posterior insula support a representation of the affective aspects of genital sensation. Conclusion In view of the erogenous character of sensations originating in the genitalia, future studies on this topic should systematically assess qualitatively as well as quantitatively the sexually stimulating and/or sexually pleasurable characteristics of sensations felt by subjects in response to experimental stimuli. PMID:25766001

The influence of signal type on the internal auditory representation of a room

NASA Astrophysics Data System (ADS)

Teret, Elizabeth

Currently, architectural acousticians make no real distinction between a room impulse response and the auditory system's internal representation of a room. With this lack of a good model for the auditory representation of a room, it is indirectly assumed that our internal representation of a room is independent of the sound source needed to make the room characteristics audible. The extent to which this assumption holds true is examined with perceptual tests. Listeners are presented with various pairs of signals (music, speech, and noise) convolved with synthesized impulse responses of different reverberation times. They are asked to adjust the reverberation of one of the signals to match the other. Analysis of the data show that the source signal significantly influences perceived reverberance. Listeners are less accurate when matching reverberation times of varied signals than they are with identical signals. Additional testing shows that perception of reverberation can be linked to the existence of transients in the signal.

Automated solar collector installation design including ability to define heterogeneous design preferences

DOEpatents

Wayne, Gary; Frumkin, Alexander; Zaydman, Michael; Lehman, Scott; Brenner, Jules

2014-04-29

Embodiments may include systems and methods to create and edit a representation of a worksite, to create various data objects, to classify such objects as various types of pre -defined "features" with attendant properties and layout constraints. As part of or in addition to classification, an embodiment may include systems and methods to create, associate, and edit intrinsic and extrinsic properties to these objects. A design engine may apply of design rules to the features described above to generate one or more solar collectors installation design alternatives, including generation of on-screen and/or paper representations of the physical layout or arrangement of the one or more design alternatives. Embodiments may also include definition of one or more design apertures, each of which may correspond to boundaries in which solar collector layouts should comply with distinct sets of user-defined design preferences. Distinct apertures may provide heterogeneous regions of collector layout according to the user-defined design preferences.

Automated solar collector installation design including ability to define heterogeneous design preferences

DOEpatents

Wayne, Gary; Frumkin, Alexander; Zaydman, Michael; Lehman, Scott; Brenner, Jules

2013-01-08

Embodiments may include systems and methods to create and edit a representation of a worksite, to create various data objects, to classify such objects as various types of pre-defined "features" with attendant properties and layout constraints. As part of or in addition to classification, an embodiment may include systems and methods to create, associate, and edit intrinsic and extrinsic properties to these objects. A design engine may apply of design rules to the features described above to generate one or more solar collectors installation design alternatives, including generation of on-screen and/or paper representations of the physical layout or arrangement of the one or more design alternatives. Embodiments may also include definition of one or more design apertures, each of which may correspond to boundaries in which solar collector layouts should comply with distinct sets of user-defined design preferences. Distinct apertures may provide heterogeneous regions of collector layout according to the user-defined design preferences.

Entorhinal Cortical Ocean Cells Encode Specific Contexts and Drive Context-Specific Fear Memory

PubMed Central

Kitamura, Takashi; Sun, Chen; Martin, Jared; Kitch, Lacey J; Schnitzer, Mark J; Tonegawa, Susumu

2016-01-01

Summary Forming distinct representations and memories of multiple contexts and episodes is thought to be a crucial function of the hippocampal-entorhinal cortical network. The hippocampal dentate gyrus (DG) and CA3 are known to contribute to these functions but the role of the entorhinal cortex (EC) is poorly understood. Here, we show that Ocean cells, excitatory stellate neurons in the medial EC layer II projecting into DG and CA3, rapidly form a distinct representation of a novel context and drive context-specific activation of downstream CA3 cells as well as context-specific fear memory. In contrast, Island cells, excitatory pyramidal neurons in the medial EC layer II projecting into CA1, are indifferent to context-specific encoding or memory. On the other hand, Ocean cells are dispensable for temporal association learning, for which Island cells are crucial. Together, the two excitatory medial EC layer II inputs to the hippocampus have complementary roles in episodic memory. PMID:26402611

Providing local color?: "cape coloreds," "cockneys," and Cape Town's identity from the late nineteenth century to the 1970s.

PubMed

Bickford-Smith, Vivian

2012-01-01

Jim Dyos, founding-father of British urban history, argued that cities have commonly acknowledged “individual characteristics” that distinguish them. Such distinctive characteristics, though usually based on material realities, are promoted through literary and visual representations. This article argues that those who seek to convey a city’s distinctiveness will do so not only through describing its particular topography, architecture, history or functions but also by describing its “local colour”: the supposedly unique customs, manner of speech, dress, or other special features of its inhabitants. In colonial cities this process involved white racial stereotyping of “others”. In Cape Town, depictions of “Coloured” inhabitants as unique “city types” became part of the city’s “destination branding”. The article analyses change and continuity in such representations. To this end it draws on the insights of Gareth Stedman Jones into changing depictions of London’s “Cockneys” and the insights of Stephen Ward into historical “place-selling”.

Different Timescales for the Neural Coding of Consonant and Vowel Sounds

PubMed Central

Perez, Claudia A.; Engineer, Crystal T.; Jakkamsetti, Vikram; Carraway, Ryan S.; Perry, Matthew S.

2013-01-01

Psychophysical, clinical, and imaging evidence suggests that consonant and vowel sounds have distinct neural representations. This study tests the hypothesis that consonant and vowel sounds are represented on different timescales within the same population of neurons by comparing behavioral discrimination with neural discrimination based on activity recorded in rat inferior colliculus and primary auditory cortex. Performance on 9 vowel discrimination tasks was highly correlated with neural discrimination based on spike count and was not correlated when spike timing was preserved. In contrast, performance on 11 consonant discrimination tasks was highly correlated with neural discrimination when spike timing was preserved and not when spike timing was eliminated. These results suggest that in the early stages of auditory processing, spike count encodes vowel sounds and spike timing encodes consonant sounds. These distinct coding strategies likely contribute to the robust nature of speech sound representations and may help explain some aspects of developmental and acquired speech processing disorders. PMID:22426334

Ciência & Saúde Coletiva: scientific production analysis and collaborative research networks.

PubMed

Conner, Norma; Provedel, Attilio; Maciel, Ethel Leonor Noia

2017-03-01

The purpose of this metric and descriptive study was to identify the most productive authors and their collaborative research networks from articles published in Ciência & Saúde Coletiva between, 2005, and 2014. Authors meeting the cutoff criteria of at least 10 articles were considered the most productive authors. VOSviewer and Network Workbench technologies were applied for visual representations of collaborative research networks involving the most productive authors in the period. Initial analysis recovered 2511 distinct articles, with 8920 total authors with an average of 3.55 authors per article. Author analysis revealed 6288 distinct authors, 24 of these authors were identified as the most productive. These 24 authors generated 287 articles with an average of 4.31 authors per article, and represented 8 separate collaborative partnerships, the largest of which had 14 authors, indicating a significant degree of collaboration among these authors. This analysis provides a visual representation of networks of knowledge development in public health and demonstrates the usefulness of VOSviewer and Network Workbench technologies in future research.

Feature Statistics Modulate the Activation of Meaning During Spoken Word Processing.

PubMed

Devereux, Barry J; Taylor, Kirsten I; Randall, Billi; Geertzen, Jeroen; Tyler, Lorraine K

2016-03-01

Understanding spoken words involves a rapid mapping from speech to conceptual representations. One distributed feature-based conceptual account assumes that the statistical characteristics of concepts' features--the number of concepts they occur in (distinctiveness/sharedness) and likelihood of co-occurrence (correlational strength)--determine conceptual activation. To test these claims, we investigated the role of distinctiveness/sharedness and correlational strength in speech-to-meaning mapping, using a lexical decision task and computational simulations. Responses were faster for concepts with higher sharedness, suggesting that shared features are facilitatory in tasks like lexical decision that require access to them. Correlational strength facilitated responses for slower participants, suggesting a time-sensitive co-occurrence-driven settling mechanism. The computational simulation showed similar effects, with early effects of shared features and later effects of correlational strength. These results support a general-to-specific account of conceptual processing, whereby early activation of shared features is followed by the gradual emergence of a specific target representation. Copyright © 2015 The Authors. Cognitive Science published by Cognitive Science Society, Inc.

Complementary codes for odor identity and intensity in olfactory cortex

PubMed Central

Bolding, Kevin A; Franks, Kevin M

2017-01-01

The ability to represent both stimulus identity and intensity is fundamental for perception. Using large-scale population recordings in awake mice, we find distinct coding strategies facilitate non-interfering representations of odor identity and intensity in piriform cortex. Simply knowing which neurons were activated is sufficient to accurately represent odor identity, with no additional information about identity provided by spike time or spike count. Decoding analyses indicate that cortical odor representations are not sparse. Odorant concentration had no systematic effect on spike counts, indicating that rate cannot encode intensity. Instead, odor intensity can be encoded by temporal features of the population response. We found a subpopulation of rapid, largely concentration-invariant responses was followed by another population of responses whose latencies systematically decreased at higher concentrations. Cortical inhibition transforms olfactory bulb output to sharpen these dynamics. Our data therefore reveal complementary coding strategies that can selectively represent distinct features of a stimulus. DOI: http://dx.doi.org/10.7554/eLife.22630.001 PMID:28379135

Balkanizing the primate orbitofrontal cortex: distinct subregions for comparing and contrasting values.

PubMed

Rudebeck, Peter H; Murray, Elisabeth A

2011-12-01

The primate orbitofrontal cortex (OFC) is often treated as a single entity, but architectonic and connectional neuroanatomy indicate that it has distinguishable parts. Nevertheless, few studies have attempted to dissociate the functions of its subregions. Here we review findings from recent neuropsychological and neurophysiological studies that do so. The lateral OFC seems to be important for learning, representing, and updating specific object-reward associations. The medial OFC seems to be important for value comparisons and choosing among objects on that basis. Rather than viewing this dissociation of function in terms of learning versus choosing, however, we suggest that it reflects the distinction between contrasts and comparisons: differences versus similarities. Making use of high-dimensional representations that arise from the convergence of several sensory modalities, the lateral OFC encodes contrasts among outcomes. The medial OFC reduces these contrasting representations of value to a single dimension, a common currency, in order to compare alternative choices. © 2011 New York Academy of Sciences.

Site-level model intercomparison of high latitude and high altitude soil thermal dynamics in tundra and barren landscapes

NASA Astrophysics Data System (ADS)

Ekici, A.; Chadburn, S.; Chaudhary, N.; Hajdu, L. H.; Marmy, A.; Peng, S.; Boike, J.; Burke, E.; Friend, A. D.; Hauck, C.; Krinner, G.; Langer, M.; Miller, P. A.; Beer, C.

2015-07-01

Modeling soil thermal dynamics at high latitudes and altitudes requires representations of physical processes such as snow insulation, soil freezing and thawing and subsurface conditions like soil water/ice content and soil texture. We have compared six different land models: JSBACH, ORCHIDEE, JULES, COUP, HYBRID8 and LPJ-GUESS, at four different sites with distinct cold region landscape types, to identify the importance of physical processes in capturing observed temperature dynamics in soils. The sites include alpine, high Arctic, wet polygonal tundra and non-permafrost Arctic, thus showing how a range of models can represent distinct soil temperature regimes. For all sites, snow insulation is of major importance for estimating topsoil conditions. However, soil physics is essential for the subsoil temperature dynamics and thus the active layer thicknesses. This analysis shows that land models need more realistic surface processes, such as detailed snow dynamics and moss cover with changing thickness and wetness, along with better representations of subsoil thermal dynamics.

Beyond the FFA: The Role of the Ventral Anterior Temporal Lobes in Face Processing

PubMed Central

Collins, Jessica A.; Olson, Ingrid R.

2014-01-01

Extensive research has supported the existence of a specialized face-processing network that is distinct from the visual processing areas used for general object recognition. The majority of this work has been aimed at characterizing the response properties of the fusiform face area (FFA) and the occipital face area (OFA), which together are thought to constitute the core network of brain areas responsible for facial identification. Although accruing evidence has shown that face-selective patches in the ventral anterior temporal lobes (vATLs) are interconnected with the FFA and OFA, and that they play a role in facial identification, the relative contribution of these brain areas to the core face-processing network has remained unarticulated. Here we review recent research critically implicating the vATLs in face perception and memory. We propose that current models of face processing should be revised such that the ventral anterior temporal lobes serve a centralized role in the visual face-processing network. We speculate that a hierarchically organized system of face processing areas extends bilaterally from the inferior occipital gyri to the vATLs, with facial representations becoming increasingly complex and abstracted from low-level perceptual features as they move forward along this network. The anterior temporal face areas may serve as the apex of this hierarchy, instantiating the final stages of face recognition. We further argue that the anterior temporal face areas are ideally suited to serve as an interface between face perception and face memory, linking perceptual representations of individual identity with person-specific semantic knowledge. PMID:24937188

Detecting representations of recent and remote autobiographical memories in vmPFC and hippocampus

PubMed Central

Bonnici, Heidi M.; Chadwick, Martin J.; Lutti, Antoine; Hassabis, Demis; Weiskopf, Nikolaus; Maguire, Eleanor A.

2012-01-01

How autobiographical memories are represented in the human brain and whether this changes with time are questions central to memory neuroscience. Two regions in particular have been consistently implicated, the ventromedial prefrontal cortex (vmPFC) and the hippocampus, although their precise contributions are still contested. The key question in this debate, when reduced to its simplest form, concerns where information about specific autobiographical memories is located. Here we availed ourselves of the opportunity afforded by multi-voxel pattern analysis (MVPA) to provide an alternative to conventional neuropsychological and fMRI approaches, by detecting representations of individual autobiographical memories in patterns of fMRI activity. We examined whether information about specific recent (two weeks old) and remote (ten years old) autobiographical memories was represented in vmPFC and hippocampus, and other medial temporal and neocortical regions. vmPFC contained information about recent and remote autobiographical memories, although remote memories were more readily detected there, indicating that consolidation or a change of some kind had occurred. Information about both types of memory was also present in the hippocampus, suggesting it plays a role in the retrieval of vivid autobiographical memories regardless of remoteness. Interestingly, we also found that while recent and remote memories were both represented within anterior and posterior hippocampus, the latter nevertheless contained more information about remote memories. Thus, like vmPFC, the hippocampus too respected the distinction between recent and remote memories. Overall, these findings clarify and extend our view of vmPFC and hippocampus while also informing systems-level consolidation and providing clear targets for future studies. PMID:23175849

Students’ mathematical representations on secondary school in solving trigonometric problems

NASA Astrophysics Data System (ADS)

Istadi; Kusmayadi, T. A.; Sujadi, I.

2017-06-01

This research aimed to analyse students’ mathematical representations on secondary school in solving trigonometric problems. This research used qualitative method. The participants were 4 students who had high competence of knowledge taken from 20 students of 12th natural-science grade SMAN-1 Kota Besi, Central Kalimantan. Data validation was carried out using time triangulation. Data analysis used Huberman and Miles stages. The results showed that their answers were not only based on the given figure, but also used the definition of trigonometric ratio on verbal representations. On the other hand, they were able to determine the object positions to be observed. However, they failed to determine the position of the angle of depression at the sketches made on visual representations. Failure in determining the position of the angle of depression to cause an error in using the mathematical equation. Finally, they were unsuccessful to use the mathematical equation properly on symbolic representations. From this research, we could recommend the importance of translations between mathematical problems and mathematical representations as well as translations among mathematical representaions (verbal, visual, and symbolic) in learning mathematics in the classroom.

Spatiotemporal dynamics of similarity-based neural representations of facial identity.

PubMed

Vida, Mark D; Nestor, Adrian; Plaut, David C; Behrmann, Marlene

2017-01-10

Humans' remarkable ability to quickly and accurately discriminate among thousands of highly similar complex objects demands rapid and precise neural computations. To elucidate the process by which this is achieved, we used magnetoencephalography to measure spatiotemporal patterns of neural activity with high temporal resolution during visual discrimination among a large and carefully controlled set of faces. We also compared these neural data to lower level "image-based" and higher level "identity-based" model-based representations of our stimuli and to behavioral similarity judgments of our stimuli. Between ∼50 and 400 ms after stimulus onset, face-selective sources in right lateral occipital cortex and right fusiform gyrus and sources in a control region (left V1) yielded successful classification of facial identity. In all regions, early responses were more similar to the image-based representation than to the identity-based representation. In the face-selective regions only, responses were more similar to the identity-based representation at several time points after 200 ms. Behavioral responses were more similar to the identity-based representation than to the image-based representation, and their structure was predicted by responses in the face-selective regions. These results provide a temporally precise description of the transformation from low- to high-level representations of facial identity in human face-selective cortex and demonstrate that face-selective cortical regions represent multiple distinct types of information about face identity at different times over the first 500 ms after stimulus onset. These results have important implications for understanding the rapid emergence of fine-grained, high-level representations of object identity, a computation essential to human visual expertise.

Force Concept Inventory-based multiple-choice test for investigating students' representational consistency

NASA Astrophysics Data System (ADS)

Nieminen, Pasi; Savinainen, Antti; Viiri, Jouni

2010-07-01

This study investigates students’ ability to interpret multiple representations consistently (i.e., representational consistency) in the context of the force concept. For this purpose we developed the Representational Variant of the Force Concept Inventory (R-FCI), which makes use of nine items from the 1995 version of the Force Concept Inventory (FCI). These original FCI items were redesigned using various representations (such as motion map, vectorial and graphical), yielding 27 multiple-choice items concerning four central concepts underpinning the force concept: Newton’s first, second, and third laws, and gravitation. We provide some evidence for the validity and reliability of the R-FCI; this analysis is limited to the student population of one Finnish high school. The students took the R-FCI at the beginning and at the end of their first high school physics course. We found that students’ (n=168) representational consistency (whether scientifically correct or not) varied considerably depending on the concept. On average, representational consistency and scientifically correct understanding increased during the instruction, although in the post-test only a few students performed consistently both in terms of representations and scientifically correct understanding. We also compared students’ (n=87) results of the R-FCI and the FCI, and found that they correlated quite well.

Evidence from machines that learn and think like people.

PubMed

Forbus, Kenneth D; Gentner, Dedre

2017-01-01

We agree with Lake et al.'s trenchant analysis of deep learning systems, including that they are highly brittle and that they need vastly more examples than do people. We also agree that human cognition relies heavily on structured relational representations. However, we differ in our analysis of human cognitive processing. We argue that (1) analogical comparison processes are central to human cognition; and (2) intuitive physical knowledge is captured by qualitative representations, rather than quantitative simulations.

Alterations in central motor representation increase over time in individuals with rotator cuff tendinopathy.

PubMed

Ngomo, Suzy; Mercier, Catherine; Bouyer, Laurent J; Savoie, Alexandre; Roy, Jean-Sébastien

2015-02-01

To investigate whether rotator cuff tendinopathy leads to changes in central motor representation of a rotator cuff muscle, and to assess whether such changes are related to pain intensity, pain duration, and physical disability. Using transcranial magnetic stimulation, motor representation of infraspinatus muscle was assessed bilaterally in patients with unilateral rotator cuff tendinopathy. Active motor threshold is significantly larger for the affected shoulder comparatively to the unaffected shoulder (n=39, p=0.01), indicating decreased corticospinal excitability on the affected side compared to unaffected side. Further, results suggest that this asymmetry in corticospinal excitability is associated with duration of pain (n=39; r=0.45; p=0.005), but not with pain intensity (n=39; r<0.03; p>0.43). In contrast with findings in other populations with musculoskeletal pain, no significant inter-hemispheric asymmetry was observed in map location (n=16; p-values ⩾ 0.91), or in the amplitude of motor responses obtained at various stimulation intensities (n=16; p=0.83). Chronicity of pain, but not its intensity, appears to be a factor related to lower excitability of infraspinatus representation. These results support the view that while cortical reorganization correlates with magnitude of pain in neuropathic pain syndromes, it could be more related to chronicity in the case of musculoskeletal disorders. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

How the past weighs on the present: social representations of history and their role in identity politics.

PubMed

Liu, James H; Hilton, Denis J

2005-12-01

Socially shared representations of history have been important in creating, maintaining and changing a people's identity. Their management and negotiation are central to interethnic and international relations. We present a narrative framework to represent how collectively significant events become (selectively) incorporated in social representations that enable positioning of ethnic, national and supranational identities. This perspective creates diachronic (temporal) links between the functional (e.g. realistic conflict theory), social identity, and cognitive perspectives on intergroup relations. The charters embedded in these representations condition nations with similar interests to adopt different political stances in dealing with current events, and can influence the perceived stability and legitimacy of social orders. They are also instrumental in determining social identity strategies for reacting to negative social comparisons, and can influence the relationships between national and ethnic identities.

Spectroscopy of SU(4) composite Higgs theory with two distinct fermion representations

NASA Astrophysics Data System (ADS)

Ayyar, Venkitesh; DeGrand, Thomas; Golterman, Maarten; Hackett, Daniel C.; Jay, William I.; Neil, Ethan T.; Shamir, Yigal; Svetitsky, Benjamin

2018-04-01

We have simulated the SU(4) lattice gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations simultaneously. Such theories arise naturally in the context of composite Higgs models that include a partially composite top quark. We describe the low-lying meson spectrum of the theory and fit the pseudoscalar masses and decay constants to chiral perturbation theory. We infer as well the mass and decay constant of the Goldstone boson corresponding to the nonanomalous U(1) symmetry of the model. Our results are broadly consistent with large-Nc scaling and vector-meson dominance.

A framework for investigating animal consciousness.

PubMed

Droege, Paula; Braithwaite, Victoria A

2015-01-01

An assessment of consciousness in nonverbal animals requires a framework for research that extends testing methods beyond subjective report. This chapter proposes a working definition of consciousness in terms of temporal representation that provides the critical link between internal phenomenology and external behavior and neural structure. Our claim is that consciousness represents the present moment as distinct from the past and the future in order to flexibly respond to stimuli. We discuss behavioral and neural evidence that indicates the capacity for both flexible response and temporal representation, and we illustrate these capacities in fish, a taxonomic group that challenges human intuitions about consciousness.

Selective Attention Enhances Beta-Band Cortical Oscillation to Speech under “Cocktail-Party” Listening Conditions

PubMed Central

Gao, Yayue; Wang, Qian; Ding, Yu; Wang, Changming; Li, Haifeng; Wu, Xihong; Qu, Tianshu; Li, Liang

2017-01-01

Human listeners are able to selectively attend to target speech in a noisy environment with multiple-people talking. Using recordings of scalp electroencephalogram (EEG), this study investigated how selective attention facilitates the cortical representation of target speech under a simulated “cocktail-party” listening condition with speech-on-speech masking. The result shows that the cortical representation of target-speech signals under the multiple-people talking condition was specifically improved by selective attention relative to the non-selective-attention listening condition, and the beta-band activity was most strongly modulated by selective attention. Moreover, measured with the Granger Causality value, selective attention to the single target speech in the mixed-speech complex enhanced the following four causal connectivities for the beta-band oscillation: the ones (1) from site FT7 to the right motor area, (2) from the left frontal area to the right motor area, (3) from the central frontal area to the right motor area, and (4) from the central frontal area to the right frontal area. However, the selective-attention-induced change in beta-band causal connectivity from the central frontal area to the right motor area, but not other beta-band causal connectivities, was significantly correlated with the selective-attention-induced change in the cortical beta-band representation of target speech. These findings suggest that under the “cocktail-party” listening condition, the beta-band oscillation in EEGs to target speech is specifically facilitated by selective attention to the target speech that is embedded in the mixed-speech complex. The selective attention-induced unmasking of target speech may be associated with the improved beta-band functional connectivity from the central frontal area to the right motor area, suggesting a top-down attentional modulation of the speech-motor process. PMID:28239344

Selective Attention Enhances Beta-Band Cortical Oscillation to Speech under "Cocktail-Party" Listening Conditions.

PubMed

Gao, Yayue; Wang, Qian; Ding, Yu; Wang, Changming; Li, Haifeng; Wu, Xihong; Qu, Tianshu; Li, Liang

2017-01-01

Human listeners are able to selectively attend to target speech in a noisy environment with multiple-people talking. Using recordings of scalp electroencephalogram (EEG), this study investigated how selective attention facilitates the cortical representation of target speech under a simulated "cocktail-party" listening condition with speech-on-speech masking. The result shows that the cortical representation of target-speech signals under the multiple-people talking condition was specifically improved by selective attention relative to the non-selective-attention listening condition, and the beta-band activity was most strongly modulated by selective attention. Moreover, measured with the Granger Causality value, selective attention to the single target speech in the mixed-speech complex enhanced the following four causal connectivities for the beta-band oscillation: the ones (1) from site FT7 to the right motor area, (2) from the left frontal area to the right motor area, (3) from the central frontal area to the right motor area, and (4) from the central frontal area to the right frontal area. However, the selective-attention-induced change in beta-band causal connectivity from the central frontal area to the right motor area, but not other beta-band causal connectivities, was significantly correlated with the selective-attention-induced change in the cortical beta-band representation of target speech. These findings suggest that under the "cocktail-party" listening condition, the beta-band oscillation in EEGs to target speech is specifically facilitated by selective attention to the target speech that is embedded in the mixed-speech complex. The selective attention-induced unmasking of target speech may be associated with the improved beta-band functional connectivity from the central frontal area to the right motor area, suggesting a top-down attentional modulation of the speech-motor process.

The Representation of Orientation in Macaque V2: Four Stripes Not Three

PubMed Central

Felleman, Daniel J.; Lim, Heejin; Xiao, Youping; Wang, Yi; Eriksson, Anastasia; Parajuli, Arun

2015-01-01

Area V2 of macaque monkeys is traditionally thought to consist of 3 distinct functional compartments with characteristic cortical connections and functional properties. Orientation selectivity is one property that has frequently been used to distinguish V2 stripes, however, this receptive field property has been found in a high percentage of neurons across V2 compartments. Using quantitative intrinsic cortical imaging, we derived maps of preferred orientation, orientation selectivity, and orientation gradient in thin stripes, thick stripes, and interstripes in area V2. Orientation-selective responses were found in each V2 stripe, but the magnitude and organization of orientation selectivity differed significantly from stripe to stripe. Remarkably, the 2 pale stripes flanking each cytochrome oxidase dense stripe differed significantly in their representation of orientation resulting in their distinction as type-I and type-II interstripes. V2 orientation maps are characterized by clockwise and anticlockwise “orientation pinwheels”, but unlike V1, they are not homogeneously distributed across V2. Furthermore, V2 stripes contain large-scale sequences of preferred orientation. These analyses demonstrate that V2 consists of 4 distinct functional compartments; thick stripes and type-II interstripes, which are strongly orientation selective and thin stripes and type-I interstripes, which are significantly less selective for orientation and exhibit larger orientation gradient magnitudes. PMID:24614951

Cooperative interactions between hippocampal and striatal systems support flexible navigation

PubMed Central

Brown, Thackery I; Ross, Robert S; Tobyne, Sean M; Stern, Chantal E

2012-01-01

Research in animals and humans has demonstrated that the hippocampus is critical for retrieving distinct representations of overlapping sequences of information. There is recent evidence that the caudate nucleus and orbitofrontal cortex are also involved in disambiguation of overlapping spatial representations. The hippocampus and caudate are functionally distinct regions, but both have anatomical links with the orbitofrontal cortex. The present study used an fMRI-based functional connectivity analysis in humans to examine the functional relationship between the hippocampus, caudate, and orbitofrontal cortex when participants use contextual information to navigate well-learned spatial routes which share common elements. Participants were trained outside the scanner to navigate virtual mazes from a first-person perspective. Overlapping condition mazes began and ended at distinct locations, but converged in the middle to share some hallways with another maze. Non-overlapping condition mazes did not share any hallways with any other maze. Successful navigation through the overlapping hallways required contextual information identifying the current navigational route to guide the appropriate response for a given trial. Results revealed greater functional connectivity between the hippocampus, caudate, and orbitofrontal cortex for overlapping mazes compared to non-overlapping mazes. The current findings suggest that the hippocampus and caudate interact with prefrontal structures cooperatively for successful contextually-dependent navigation. PMID:22266411

Semantic Feature Distinctiveness and Frequency

ERIC Educational Resources Information Center

Lamb, Katherine M.

2012-01-01

Lexical access is the process in which basic components of meaning in language, the lexical entries (words) are activated. This activation is based on the organization and representational structure of the lexical entries. Semantic features of words, which are the prominent semantic characteristics of a word concept, provide important information…

Identity, Aesthetics, Objects

ERIC Educational Resources Information Center

Guerra, Gustavo

2006-01-01

In September 1990 UCLA's Wright Art Gallery opened an exhibition entitled Chicano Art: Resistance and Affirmation 1965-1985 (now usually referred to as CARA). While CARA was one of several national events displaying nonmainstream art, it was also distinctive in its politics of self-representation. The artists participating in CARA insisted that…

Teaching Linear Measurement Concepts. . .K to 6

ERIC Educational Resources Information Center

Norrie, A. L.

1974-01-01

Three distinct, but overlapping, stages in measurement are identified as intuitive thinking, logical thinking, and formal operations. Three types of representation are body units, non-standard, and standard units. Instructional sequences and activities are suggested for grades 1-3 and grades 4-6 based on these considerations. (LS)

Interactivity in Prosodic Representations in Children

ERIC Educational Resources Information Center

Goffman, Lisa; Westover, Stefanie

2013-01-01

The aim of this study was to determine, using speech error and articulatory analyses, whether the binary distinction between iambs and trochees should be extended to include additional prosodic subcategories. Adults, children who are normally developing, and children with specific language impairment (SLI) participated. Children with SLI were…

Toward an Aristotelian Model of Teacher Reasoning.

ERIC Educational Resources Information Center

Orton, Robert E.

1997-01-01

Utilizes Aristotle's three-way distinctions between theory, practice, and production to describe a balanced model of teacher reasoning. Reviews differing models of teacher reasoning that emphasize the role of contemplation and subject-matter representations. Uses the Aristotelian model to point toward a normative vision of teacher reasoning. (MJP)

Global Academe: Engaging Intellectual Discourse

ERIC Educational Resources Information Center

Nagy-Zekmi, Silvia, Ed.; Hollis, Karyn, Ed.

2012-01-01

The representation of the economic, political, cultural and, more importantly, global interrelations between agents involved in the process of intellectual activity is at the core of the inquiry in this volume that scrutinizes a distinct transformation occurring in the modalities of intellectual production also detectable in the changing role of…

Category representations in the brain are both discretely localized and widely distributed.

PubMed

Shehzad, Zarrar; McCarthy, Gregory

2018-06-01

Whether category information is discretely localized or represented widely in the brain remains a contentious issue. Initial functional MRI studies supported the localizationist perspective that category information is represented in discrete brain regions. More recent fMRI studies using machine learning pattern classification techniques provide evidence for widespread distributed representations. However, these latter studies have not typically accounted for shared information. Here, we find strong support for distributed representations when brain regions are considered separately. However, localized representations are revealed by using analytical methods that separate unique from shared information among brain regions. The distributed nature of shared information and the localized nature of unique information suggest that brain connectivity may encourage spreading of information but category-specific computations are carried out in distinct domain-specific regions. NEW & NOTEWORTHY Whether visual category information is localized in unique domain-specific brain regions or distributed in many domain-general brain regions is hotly contested. We resolve this debate by using multivariate analyses to parse functional MRI signals from different brain regions into unique and shared variance. Our findings support elements of both models and show information is initially localized and then shared among other regions leading to distributed representations being observed.

Language Networks as Models of Cognition: Understanding Cognition through Language

NASA Astrophysics Data System (ADS)

Beckage, Nicole M.; Colunga, Eliana

Language is inherently cognitive and distinctly human. Separating the object of language from the human mind that processes and creates language fails to capture the full language system. Linguistics traditionally has focused on the study of language as a static representation, removed from the human mind. Network analysis has traditionally been focused on the properties and structure that emerge from network representations. Both disciplines could gain from looking at language as a cognitive process. In contrast, psycholinguistic research has focused on the process of language without committing to a representation. However, by considering language networks as approximations of the cognitive system we can take the strength of each of these approaches to study human performance and cognition as related to language. This paper reviews research showcasing the contributions of network science to the study of language. Specifically, we focus on the interplay of cognition and language as captured by a network representation. To this end, we review different types of language network representations before considering the influence of global level network features. We continue by considering human performance in relation to network structure and conclude with theoretical network models that offer potential and testable explanations of cognitive and linguistic phenomena.

A Developmental Guide to the Organisation of Close Relationships

PubMed Central

Laursen, Brett; Bukowski, William M.

2009-01-01

A developmental guide to close relationships is presented. Parent-child, sibling, friend, and romantic relationships are described along dimensions that address permanence, power, and gender. These dimensions describe relationship differences in organisational principles that encompass internal representations, social understanding, and interpersonal experiences. The concept of domain specificity is borrowed from cognitive development to address the shifting developmental dynamics of close relationships. Distinct relationships are organised around distinct socialisation tasks, so each relationship requires its own organisational system. As a consequence, different principles guide different relationships, and these organisational principles change with development. PMID:20090927

Imaging empathy and prosocial emotions.

PubMed

Lamm, Claus; Rütgen, Markus; Wagner, Isabella C

2017-06-29

Empathy is a multi-faceted construct with important implications for social behavior. Based on a selective review of the neuroscientific evidence collected in humans, the present paper discusses the neural representations underlying affect sharing, its relation to mentalizing, the importance of self-other distinction, the distinction between empathy, sympathy and compassion, and how these phenomena are linked to prosocial behavior. Apart from reviewing the literature, we also highlight open questions and how they might be addressed by a research approach that tries to integrate across these diverse constructs. Copyright © 2017 Elsevier B.V. All rights reserved.

Hue-specific colour memory impairment in an individual with intact colour perception and colour naming.

PubMed

Jakobson, L S; Pearson, P M; Robertson, B

2008-01-15

Cases of hue-selective dyschomatopsias, together with the results of recent optical imaging studies [Xiao, Y., Casti, A. R. R., Xiao, J., & Kaplan, E. (2006). A spatially organized representation of colour in macaque primary visual cortex. Perception, 35, ECVP Abstract Supplement; Xiao, Y., Wang, Y., & Felleman, D. J. (2003). A spatially organized representation of colour in macaque cortical area V2. Nature, 421, 535-539], have provided support for the idea that different colours are processed in spatially distinct regions of extrastriate cortex. In the present report, we provide evidence suggesting that a similar, but distinct, map may exist for representations of colour in memory. This evidence comes from observations of a young woman (QP) who demonstrates an isolated deficit in colour memory secondary to a concussive episode. Despite having normal colour perception and colour naming skills, and above-average memory skills in other domains, QP's ability to recall visually encoded colour information over short retention intervals is dramatically impaired. Her long-term memory for colour and her colour imagery skills are also abnormal. Surprisingly, however, these impairments are not seen with all hues; specifically, her ability to remember or imagine blue shades is spared. This interesting case contributes to the literature suggesting that colour perception, naming, and memory can be clinically dissociated, and provides insights into the organization of colour information in memory.

Evaluation of bulk heat fluxes from atmospheric datasets

NASA Astrophysics Data System (ADS)

Farmer, Benton

Heat fluxes at the air-sea interface are an important component of the Earth's heat budget. In addition, they are an integral factor in determining the sea surface temperature (SST) evolution of the oceans. Different representations of these fluxes are used in both the atmospheric and oceanic communities for the purpose of heat budget studies and, in particular, for forcing oceanic models. It is currently difficult to quantify the potential impact varying heat flux representations have on the ocean response. In this study, a diagnostic tool is presented that allows for a straightforward comparison of surface heat flux formulations and atmospheric data sets. Two variables, relaxation time (RT) and the apparent temperature (T*), are derived from the linearization of the bulk formulas. They are then calculated to compare three bulk formulae and five atmospheric datasets. Additionally, the linearization is expanded to the second order to compare the amount of residual flux present. It is found that the use of a bulk formula employing a constant heat transfer coefficient produces longer relaxation times and contains a greater amount of residual flux in the higher order terms of the linearization. Depending on the temperature difference, the residual flux remaining in the second order and above terms can reach as much as 40--50% of the total residual on a monthly time scale. This is certainly a non-negligible residual flux. In contrast, a bulk formula using a stability and wind dependent transfer coefficient retains much of the total flux in the first order term, as only a few percent remain in the residual flux. Most of the difference displayed among the bulk formulas stems from the sensitivity to wind speed and the choice of a constant or spatially varying transfer coefficient. Comparing the representation of RT and T* provides insight into the differences among various atmospheric datasets. In particular, the representations of the western boundary current, upwelling, and the Indian monsoon regions of the oceans have distinct characteristics within each dataset. Localized regions, such as the eastern Mexican and Central American coasts, are also shown to have variability among the datasets. The use of this technique for the evaluation of bulk formulae and datasets is an efficient method for identifying the unique characteristics of each. Furthermore, insight into the heat fluxes produced by particular bulk formula or dataset can be gained.

Visualizing the engram: learning stabilizes odor representations in the olfactory network.

PubMed

Shakhawat, Amin M D; Gheidi, Ali; Hou, Qinlong; Dhillon, Sandeep K; Marrone, Diano F; Harley, Carolyn W; Yuan, Qi

2014-11-12

The nature of memory is a central issue in neuroscience. How does our representation of the world change with learning and experience? Here we use the transcription of Arc mRNA, which permits probing the neural representations of temporally separated events, to address this in a well characterized odor learning model. Rat pups readily associate odor with maternal care. In pups, the lateralized olfactory networks are independent, permitting separate training and within-subject control. We use multiday training to create an enduring memory of peppermint odor. Training stabilized rewarded, but not nonrewarded, odor representations in both mitral cells and associated granule cells of the olfactory bulb and in the pyramidal cells of the anterior piriform cortex. An enlarged core of stable, likely highly active neurons represent rewarded odor at both stages of the olfactory network. Odor representations in anterior piriform cortex were sparser than typical in adult rat and did not enlarge with learning. This sparser representation of odor is congruent with the maturation of lateral olfactory tract input in rat pups. Cortical representations elsewhere have been shown to be highly variable in electrophysiological experiments, suggesting brains operate normally using dynamic and network-modulated representations. The olfactory cortical representations here are consistent with the generalized associative model of sparse variable cortical representation, as normal responses to repeated odors were highly variable (∼70% of the cells change as indexed by Arc). Learning and memory modified rewarded odor ensembles to increase stability in a core representational component. Copyright © 2014 the authors 0270-6474/14/3415394-08$15.00/0.

Multimedia Learning: Beyond Modality. Commentary.

ERIC Educational Resources Information Center

Reimann, P.

2003-01-01

Identifies and summarizes instructional messages in the articles in this theme issue and also identifies central theoretical issues, focusing on: (1) external representations; (2) dual coding theory; and (3) the effects of animations on learning. (SLD)

Social representations of HIV/AIDS in Central and Eastern Europe.

PubMed

Goodwin, Robin; Kozlova, Alexandra; Kwiatkowska, Anna; Anh Nguyen Luu, Lan; Nizharadze, George; Realo, Anu; Külvet, Ahto; Rämmer, Andu

2003-04-01

Although a relatively recent epidemic, HIV is now increasing in Eastern Europe faster than anywhere else in the world. In the study reported in this paper, we interviewed 511 business people and health professionals in five Central and Eastern European nations: Estonia, Georgia, Hungary, Poland and Russia, deriving our questions primarily from a Social Representations perspective. Respondents also freely completed their associations with the stimulus word 'AIDS'. Our findings indicate that, although there is considerable agreement about the threat posed by the epidemic, there are also notable cultural differences in attributions about the origin and spread of the virus and the nature of those groups at risk of infection. These findings are interpreted in the light of the historical legacies of the Communist era, as well as the real economic and social challenges faced by the population of this region.

When math operations have visuospatial meanings versus purely symbolic definitions: Which solving stages and brain regions are affected?

PubMed

Pyke, Aryn A; Fincham, Jon M; Anderson, John R

2017-06-01

How does processing differ during purely symbolic problem solving versus when mathematical operations can be mentally associated with meaningful (here, visuospatial) referents? Learners were trained on novel math operations (↓, ↑), that were defined strictly symbolically or in terms of a visuospatial interpretation (operands mapped to dimensions of shaded areas, answer = total area). During testing (scanner session), no visuospatial representations were displayed. However, we expected visuospatially-trained learners to form mental visuospatial representations for problems, and exhibit distinct activations. Since some solution intervals were long (~10s) and visuospatial representations might only be instantiated in some stages during solving, group differences were difficult to detect when treating the solving interval as a whole. However, an HSMM-MVPA process (Anderson and Fincham, 2014a) to parse fMRI data identified four distinct problem-solving stages in each group, dubbed: 1) encode; 2) plan; 3) compute; and 4) respond. We assessed stage-specific differences across groups. During encoding, several regions implicated in general semantic processing and/or mental imagery were more active in visuospatially-trained learners, including: bilateral supramarginal, precuneus, cuneus, parahippocampus, and left middle temporal regions. Four of these regions again emerged in the computation stage: precuneus, right supramarginal/angular, left supramarginal/inferior parietal, and left parahippocampal gyrus. Thus, mental visuospatial representations may not just inform initial problem interpretation (followed by symbolic computation), but may scaffold on-going computation. In the second stage, higher activations were found among symbolically-trained solvers in frontal regions (R. medial and inferior and L. superior) and the right angular and middle temporal gyrus. Activations in contrasting regions may shed light on solvers' degree of use of symbolic versus mental visuospatial strategies, even in absence of behavioral differences. Copyright © 2017 Elsevier Inc. All rights reserved.

On the elimination of the electronic structure bottleneck in on the fly nonadiabatic dynamics for small to moderate sized (10-15 atom) molecules using fit diabatic representations based solely on ab initio electronic structure data: The photodissociation of phenol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Xiaolei, E-mail: virtualzx@gmail.com; Yarkony, David R., E-mail: yarkony@jhu.edu

2016-01-14

In this work, we demonstrate that for moderate sized systems, here a system with 13 atoms, global coupled potential energy surfaces defined for several electronic states over a wide energy range and for distinct regions of nuclear coordinate space characterized by distinct electron configurations, can be constructed with precise energetics and an excellent description of non-adiabatic interactions in all regions. This is accomplished using a recently reported algorithm for constructing quasi-diabatic representations, H{sup d}, of adiabatic electronic states coupled by conical intersections. In this work, the algorithm is used to construct an H{sup d} to describe the photodissociation of phenolmore » from its first and second excited electronic states. The representation treats all 33 internal degrees of freedom in an even handed manner. The ab initio adiabatic electronic structure data used to construct the fit are obtained exclusively from multireference configuration interaction with single and double excitation wave functions comprised of 88 × 10{sup 6} configuration state functions, at geometries determined by quasi-classical trajectories. Since the algorithm uses energy gradients and derivative couplings in addition to electronic energies to construct H{sup d}, data at only 7379 nuclear configurations are required to construct a representation, which describes all nuclear configurations involved in H atom photodissociation to produce the phenoxyl radical in its ground or first excited electronic state, with a mean unsigned energy error of 202.9 cm{sup −1} for electronic energies <60 000 cm{sup −1}.« less

Towards an understanding of the mechanisms of weak central coherence effects: experiments in visual configural learning and auditory perception.

PubMed

Plaisted, Kate; Saksida, Lisa; Alcántara, José; Weisblatt, Emma

2003-02-28

The weak central coherence hypothesis of Frith is one of the most prominent theories concerning the abnormal performance of individuals with autism on tasks that involve local and global processing. Individuals with autism often outperform matched nonautistic individuals on tasks in which success depends upon processing of local features, and underperform on tasks that require global processing. We review those studies that have been unable to identify the locus of the mechanisms that may be responsible for weak central coherence effects and those that show that local processing is enhanced in autism but not at the expense of global processing. In the light of these studies, we propose that the mechanisms which can give rise to 'weak central coherence' effects may be perceptual. More specifically, we propose that perception operates to enhance the representation of individual perceptual features but that this does not impact adversely on representations that involve integration of features. This proposal was supported in the two experiments we report on configural and feature discrimination learning in high-functioning children with autism. We also examined processes of perception directly, in an auditory filtering task which measured the width of auditory filters in individuals with autism and found that the width of auditory filters in autism were abnormally broad. We consider the implications of these findings for perceptual theories of the mechanisms underpinning weak central coherence effects.

The View from "Outer Britain"

ERIC Educational Resources Information Center

Rees, Gareth

2007-01-01

In the UK, there remains an economy of "outer Britain" which has a higher representation of low-pay, low-skill jobs, and correspondingly, lower levels of economic growth than other parts of the country. The author discusses how the distinctive ideological complexions of Scottish and Welsh politics open the possibility of different…

Repetition Strengthens Target Recognition but Impairs Similar Lure Discrimination: Evidence for Trace Competition

ERIC Educational Resources Information Center

Reagh, Zachariah M.; Yassa, Michael A.

2014-01-01

Most theories of memory assume that representations are strengthened with repetition. We recently proposed Competitive Trace Theory, building on the hippocampus' powerful capacity to orthogonalize inputs into distinct outputs. We hypothesized that repetition elicits a similar but nonidentical memory trace, and that contextual details of…

Pattern Separation Deficits Following Damage to the Hippocampus

ERIC Educational Resources Information Center

Kirwan, C. Brock; Hartshorn, Andrew; Stark, Shauna M.; Goodrich-Hunsaker, Naomi J.; Hopkins, Ramona O.; Stark, Craig E. L.

2012-01-01

Computational models of hippocampal function propose that the hippocampus is capable of rapidly storing distinct representations through a process known as pattern separation. This prediction is supported by electrophysiological data from rodents and neuroimaging data from humans. Here, we test the prediction that damage to the hippocampus would…

The Effectiveness of Concept Mapping and Retrieval Practice as Learning Strategies in an Undergraduate Physiology Course

ERIC Educational Resources Information Center

Burdo, Joseph; O'Dwyer, Laura

2015-01-01

Concept mapping and retrieval practice are both educational methods that have separately been reported to provide significant benefits for learning in diverse settings. Concept mapping involves diagramming a hierarchical representation of relationships between distinct pieces of information, whereas retrieval practice involves retrieving…

Regional Consumer Magazines and the Ideal White Reader: Constructing and Retaining Geography as Text.

ERIC Educational Resources Information Center

Fry, Katherine

1994-01-01

Examines representations of nature and culture in the consumer magazines "Midwest Living,""Southern Living," and "Sunset." Finds distinct patterns in each that construct the Midwest, South, and West as cultural/geographic texts. Finds that the magazines' emphasis on advertising and tourism both obscures and…

Conceptual and Linguistic Representations of Kinds and Classes

ERIC Educational Resources Information Center

Prasada, Sandeep; Hennefield, Laura; Otap, Daniel

2012-01-01

We investigate the hypothesis that our conceptual systems provide two formally distinct ways of representing categories by investigating the manner in which lexical nominals (e.g., "tree," "picnic table") and phrasal nominals (e.g., "black bird," "birds that like rice") are interpreted. Four experiments found that lexical nominals may be mapped…

Enumerating Wordsworth/Accounting for Lacan.

ERIC Educational Resources Information Center

Rodman, Jeffrey

1995-01-01

Addresses one of the more serious criticisms made concerning the Lacanian concept of the Real, that made by Francois Roustang, who accuses Lacan of intentionally blurring the two distinct registers of this concept. Wordsworth's poem, "We Are Seven," illustrates the Real as pure loss through its representation of family relations,…

Impaired List Learning Is Not a General Property of Frontal Lesions

ERIC Educational Resources Information Center

Alexander, Michael P.; Stuss, Donald; Gillingham, Susan

2009-01-01

Background: List-learning tasks are frequently used to provide measures of "executive functions" that are believed necessary for successful memory performance. Small sample sizes, confounding anomia, and incomplete representation of all frontal regions have prevented consistent demonstration of distinct regional frontal effects on this task.…

Connecting Dynamic Representations of Simple Mathematical Objects with the Construction and Exploration of Conic Sections

ERIC Educational Resources Information Center

Santos-Trigo, Manuel; Espinosa-Perez, Hugo; Reyes-Rodriguez, Aaron

2008-01-01

Different technological artefacts may offer distinct opportunities for students to develop resources and strategies to formulate, comprehend and solve mathematical problems. In particular, the use of dynamic software becomes relevant to assemble geometric configurations that may help students reconstruct and examine mathematical relationships. In…

Memory Load Affects Object Individuation in 18-Month-Old Infants

ERIC Educational Resources Information Center

Zosh, Jennifer M.; Feigenson, Lisa

2012-01-01

Accurate representation of a changing environment requires individuation--the ability to determine how many numerically distinct objects are present in a scene. Much research has characterized early individuation abilities by identifying which object features infants can use to individuate throughout development. However, despite the fact that…

Neural Mechanisms of Conceptual Relations

ERIC Educational Resources Information Center

Lewis, Gwyneth A.

2017-01-01

An over-arching goal in neurolinguistic research is to characterize the neural bases of semantic representation. A particularly relevant goal concerns whether we represent features and events (a) together in a generalized semantic hub or (b) separately in distinct but complementary systems. While the left anterior temporal lobe (ATL) is strongly…

Conflicting Approaches to Reading Research and Instruction.

ERIC Educational Resources Information Center

Smith, Frank

Reading research and reading instruction can each be grouped in two distinct categories, depending on the assumed source of control for the particular reading act that is studied or taught. "Outside-in" theorists view the reading process as beginning with print and ending with some representation or interpretation inside the brain, while…

A Processing Strategy Using Visual Representation to Convey the "passe compose/imparfait" Distinction in French.

ERIC Educational Resources Information Center

Connor, Meryl

1992-01-01

An instructional technique that enlisted natural language processes by ensuring that grammatical markers made semantic sense was examined to determine its usefulness in helping adult Anglophone classroom learners to make more accurate online aspectual choices in past tense oral narrative. (32 references) (LB)

Temporal compressive sensing systems

DOEpatents

Reed, Bryan W.

2017-12-12

Methods and systems for temporal compressive sensing are disclosed, where within each of one or more sensor array data acquisition periods, one or more sensor array measurement datasets comprising distinct linear combinations of time slice data are acquired, and where mathematical reconstruction allows for calculation of accurate representations of the individual time slice datasets.

Learning Molecular Behaviour May Improve Student Explanatory Models of the Greenhouse Effect

ERIC Educational Resources Information Center

Harris, Sara E.; Gold, Anne U.

2018-01-01

We assessed undergraduates' representations of the greenhouse effect, based on student-generated concept sketches, before and after a 30-min constructivist lesson. Principal component analysis of features in student sketches revealed seven distinct and coherent explanatory models including a new "Molecular Details" model. After the…

Validity Issues in Clinical Assessment.

ERIC Educational Resources Information Center

Foster, Sharon L.; Cone, John D.

1995-01-01

Validation issues that arise with measures of constructs and behavior are addressed with reference to general reasons for using assessment procedures in clinical psychology. A distinction is made between the representational phase of validity assessment and the elaborative validity phase in which the meaning and utility of scores are examined.…

Empirical Predictions from a General Theory of Signs

ERIC Educational Resources Information Center

Oller, John W., Jr.; Chen, Liang; Oller, Stephen D.; Pan, Ning

2005-01-01

General sign theory (GST) deals with how distinct sign systems are grounded, developed with increasing abstractness over time, and differentiated in efficacies in experience and discourse. GST has 3 components: The theory of true narrative representations (TNR theory) shows that TNRs are unique in being relatively well determined with respect to…

The oral spelling profile of posterior cortical atrophy and the nature of the graphemic representation.

PubMed

Primativo, Silvia; Yong, Keir X X; Shakespeare, Timothy J; Crutch, Sebastian J

2017-01-08

Spelling is a complex cognitive task where central and peripheral components are involved in engaging resources from many different cognitive processes. The present paper aims to both characterize the oral spelling deficit in a population of patients affected by a neurodegenerative condition and to clarify the nature of the graphemic representation within the currently available spelling models. Indeed, the nature of graphemic representation as a linear or multi-componential structure is still debated. Different hypotheses have been raised about its nature in the orthographic lexicon, with one positing that graphemes are complex objects whereby quantity and identity are separately represented in orthographic representations and can thus be selectively impaired. Posterior cortical atrophy (PCA) is a neurodegenerative condition that mainly affects visuoperceptual and visuospatial functions. Spelling impairments are considered part of the disease. Nonetheless the spelling deficit has received little attention so far and often it has been interpreted in relation to peripheral impairments such as writing difficulties associated with visuoperceptual and visuospatial deficits. In the present study we provide a detailed characterization of the oral spelling profile in PCA. The data suggest that multiple deficits underpin oral spelling problems in PCA, with elements of surface and phonological dysgraphia but also suggesting the involvement of the graphemic buffer. A large phenotypic individual variability is reported. Moreover, the larger proportion and the specific nature of errors involving geminate (i.e., double) as compared to non-geminate (i.e., non-double) letters suggest that a further central impairment might be associated with the abstract graphemic representation of letter numerosity. The present study contributes to the clinical characterization of PCA and to the current debate in the cognitive literature on spelling models; findings, despite not definitive, support the hypothesis that graphemic representations are multidimensional mental objects that separately encode information about grapheme identity and quantity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Grounded understanding of abstract concepts: The case of STEM learning.

PubMed

Hayes, Justin C; Kraemer, David J M

2017-01-01

Characterizing the neural implementation of abstract conceptual representations has long been a contentious topic in cognitive science. At the heart of the debate is whether the "sensorimotor" machinery of the brain plays a central role in representing concepts, or whether the involvement of these perceptual and motor regions is merely peripheral or epiphenomenal. The domain of science, technology, engineering, and mathematics (STEM) learning provides an important proving ground for sensorimotor (or grounded) theories of cognition, as concepts in science and engineering courses are often taught through laboratory-based and other hands-on methodologies. In this review of the literature, we examine evidence suggesting that sensorimotor processes strengthen learning associated with the abstract concepts central to STEM pedagogy. After considering how contemporary theories have defined abstraction in the context of semantic knowledge, we propose our own explanation for how body-centered information, as computed in sensorimotor brain regions and visuomotor association cortex, can form a useful foundation upon which to build an understanding of abstract scientific concepts, such as mechanical force. Drawing from theories in cognitive neuroscience, we then explore models elucidating the neural mechanisms involved in grounding intangible concepts, including Hebbian learning, predictive coding, and neuronal recycling. Empirical data on STEM learning through hands-on instruction are considered in light of these neural models. We conclude the review by proposing three distinct ways in which the field of cognitive neuroscience can contribute to STEM learning by bolstering our understanding of how the brain instantiates abstract concepts in an embodied fashion.

Number-space mapping in human infants.

PubMed

de Hevia, Maria Dolores; Spelke, Elizabeth S

2010-05-01

Mature representations of number are built on a core system of numerical representation that connects to spatial representations in the form of a mental number line. The core number system is functional in early infancy, but little is known about the origins of the mapping of numbers onto space. In this article, we show that preverbal infants transfer the discrimination of an ordered series of numerosities to the discrimination of an ordered series of line lengths. Moreover, infants construct relationships between numbers and line lengths when they are habituated to unordered pairings that vary positively, but not when they are habituated to unordered pairings that vary inversely. These findings provide evidence that a predisposition to relate representations of numerical magnitude to spatial length develops early in life. A central foundation of mathematics, science, and technology therefore emerges prior to experience with language, symbol systems, or measurement devices.

Social representations of health councilors regarding the right to health and citizenship.

PubMed

Moura, Luciana Melo de; Shimizu, Helena Eri

2017-03-30

To know the structure of the social representations of right to health and citizenship of health municipal councilors. This is a qualitative study, based on the central nucleus theory of social representations, carried out in eight municipalities of the Integrated Region for the Development of the Surroundings of the Federal District, Brazil. The intentional sample consisted of municipal health councilors. Between June and December 2012, free recall questionnaires were used, of which 68 were answered with the inducing term health, and 64 with the inducing term citizenship. Data were analyzed using EVOC software and Bardin's content analysis. The representational field of the right to health is associated with the idea of universal law guaranteed by the Constitution and the Unified Health System (SUS), and of citizenship linked to rights and duties. The conceptions of right to health are understood as a condition for reaching citizenship, and citizenship as social protection.

Orienting attention to locations in internal representations.

PubMed

Griffin, Ivan C; Nobre, Anna C

2003-11-15

Three experiments investigated whether it is possible to orient selective spatial attention to internal representations held in working memory in a similar fashion to orienting to perceptual stimuli. In the first experiment, subjects were either cued to orient to a spatial location before a stimulus array was presented (pre-cue), cued to orient to a spatial location in working memory after the array was presented (retro-cue), or given no cueing information (neutral cue). The stimulus array consisted of four differently colored crosses, one in each quadrant. At the end of a trial, a colored cross (probe) was presented centrally, and subjects responded according to whether it had occurred in the array. There were equivalent patterns of behavioral costs and benefits of cueing for both pre-cues and retro-cues. A follow-up experiment used a peripheral probe stimulus requiring a decision about whether its color matched that of the item presented at the same location in the array. Replication of the behavioral costs and benefits of pre-cues and retro-cues in this experiment ruled out changes in response criteria as the only explanation for the effects. The third experiment used event-related potentials (ERPs) to compare the neural processes involved in orienting attention to a spatial location in an external versus an internal spatial representation. In this task, subjects responded according to whether a central probe stimulus occurred at the cued location in the array. There were both similarities and differences between ERPs to spatial cues toward a perception versus an internal spatial representation. Lateralized early posterior and later frontal negativities were observed for both pre- and retro-cues. Retro-cues also showed additional neural processes to be involved in orienting to an internal representation, including early effects over frontal electrodes.

Spatiotemporal dynamics of similarity-based neural representations of facial identity

PubMed Central

Vida, Mark D.; Nestor, Adrian; Plaut, David C.; Behrmann, Marlene

2017-01-01

Humans’ remarkable ability to quickly and accurately discriminate among thousands of highly similar complex objects demands rapid and precise neural computations. To elucidate the process by which this is achieved, we used magnetoencephalography to measure spatiotemporal patterns of neural activity with high temporal resolution during visual discrimination among a large and carefully controlled set of faces. We also compared these neural data to lower level “image-based” and higher level “identity-based” model-based representations of our stimuli and to behavioral similarity judgments of our stimuli. Between ∼50 and 400 ms after stimulus onset, face-selective sources in right lateral occipital cortex and right fusiform gyrus and sources in a control region (left V1) yielded successful classification of facial identity. In all regions, early responses were more similar to the image-based representation than to the identity-based representation. In the face-selective regions only, responses were more similar to the identity-based representation at several time points after 200 ms. Behavioral responses were more similar to the identity-based representation than to the image-based representation, and their structure was predicted by responses in the face-selective regions. These results provide a temporally precise description of the transformation from low- to high-level representations of facial identity in human face-selective cortex and demonstrate that face-selective cortical regions represent multiple distinct types of information about face identity at different times over the first 500 ms after stimulus onset. These results have important implications for understanding the rapid emergence of fine-grained, high-level representations of object identity, a computation essential to human visual expertise. PMID:28028220

Representations of relatedness with parents and friends and autonomous academic motivation during the late adolescence-early adulthood period: reciprocal or unidirectional effects?

PubMed

Guay, Frédéric; Marsh, Herbert W; Senécal, Caroline; Dowson, Martin

2008-12-01

The literature on the determinants of academic motivation indicates that social and affective processes connected to students' interpersonal relationships are central elements in understanding students' academic motivation and other school-related outcomes. The aim of this study was to answer the following questions: Does autonomous motivation drive representations of relatedness, do representations of relatedness drive autonomous motivation, or are these constructs reciprocally related over time? The sample consists of 834 adolescents aged 18 years (SD=1.88) who participated in a 3-year longitudinal study. Results from the structural equation models provided good support for the effect of representations of relatedness with parents on autonomous academic motivation but no convincing support for the effect of motivation on representations of relatedness with parents. In addition, no significant effect in either direction was found between representations of relatedness with friends and autonomous academic motivation. It might be important to inform parents that they may still have an influence on their adolescent's representations of relatedness and subsequently on his/her autonomous academic motivation even during the late adolescence-early adulthood period, a period when some parents may be tempted to believe that they can do little to motivate their offspring.

Domestic violence against women: representations of health professionals 1

PubMed Central

Gomes, Vera Lúcia de Oliveira; Silva, Camila Daiane; de Oliveira, Denize Cristina; Acosta, Daniele Ferreira; Amarijo, Cristiane Lopes

2015-01-01

Abstract Objective: to analyze the representations about domestic violence against women, among health professionals of Family Health Units. Method: qualitative study based on the Theory of Social Representations. Data were collected by means of evocations and interviews, treating them in the Ensemble de Programmes Pemettant L'Analyse des Evocations software - EVOC and content analysis. Results: nurses, physicians, nursing technicians and community health agents participated. The evocations were answered by 201 professionals and, of these, 64 were interviewed. The central core of this representation, comprised by the terms "aggression", "physical-aggression", "cowardice" and "lack of respect", which have negative connotations and were cited by interviewees. In the contrast zone, comprised by the terms "abuse", "abuse-power", "pain", "humiliation", "impunity", "suffering", "sadness" and "violence", two subgroups were identified. The first periphery contains the terms "fear", evoked most often, followed by "revolt", "low self-esteem" and "submission", and in the second periphery "acceptance" and "professional support". Conclusion: this is a structured representation since it contains conceptual, imagetic and attitudinal elements. The subgroups were comprised by professionals working in the rural area and by those who had completed their professional training course in or after 2004. These presented a representation of violence different from the representation of the general group, although all demonstrated a negative connotation of this phenomenon. PMID:26444175

Traveling Policies: Hijacked in Central Asia

ERIC Educational Resources Information Center

Silova, Iveta

2005-01-01

Since the collapse of the Soviet Union, Central Asian education reform discourses have become increasingly similar to distinctive Western policy discourses traveling globally across national boundaries. Tracing the trajectory of "traveling policies" in Central Asia, this article discusses the way Western education discourses have been…

Neural Representation. A Survey-Based Analysis of the Notion

PubMed Central

Vilarroya, Oscar

2017-01-01

The word representation (as in “neural representation”), and many of its related terms, such as to represent, representational and the like, play a central explanatory role in neuroscience literature. For instance, in “place cell” literature, place cells are extensively associated with their role in “the representation of space.” In spite of its extended use, we still lack a clear, universal and widely accepted view on what it means for a nervous system to represent something, on what makes a neural activity a representation, and on what is re-presented. The lack of a theoretical foundation and definition of the notion has not hindered actual research. My aim here is to identify how active scientists use the notion of neural representation, and eventually to list a set of criteria, based on actual use, that can help in distinguishing between genuine or non-genuine neural-representation candidates. In order to attain this objective, I present first the results of a survey of authors within two domains, place-cell and multivariate pattern analysis (MVPA) research. Based on the authors’ replies, and on a review of neuroscientific research, I outline a set of common properties that an account of neural representation seems to require. I then apply these properties to assess the use of the notion in two domains of the survey, place-cell and MVPA studies. I conclude by exploring a shift in the notion of representation suggested by recent literature. PMID:28900406

Task alters category representations in prefrontal but not high-level visual cortex.

PubMed

Bugatus, Lior; Weiner, Kevin S; Grill-Spector, Kalanit

2017-07-15

A central question in neuroscience is how cognitive tasks affect category representations across the human brain. Regions in lateral occipito-temporal cortex (LOTC), ventral temporal cortex (VTC), and ventro-lateral prefrontal cortex (VLFPC) constitute the extended "what" pathway, which is considered instrumental for visual category processing. However, it is unknown (1) whether distributed responses across LOTC, VTC, and VLPFC explicitly represent category, task, or some combination of both, and (2) in what way representations across these subdivisions of the extended 'what' pathway may differ. To fill these gaps in knowledge, we scanned 12 participants using fMRI to test the effect of category and task on distributed responses across LOTC, VTC, and VLPFC. Results reveal that task and category modulate responses in both high-level visual regions, as well as prefrontal cortex. However, we found fundamentally different types of representations across the brain. Distributed responses in high-level visual regions are more strongly driven by category than task, and exhibit task-independent category representations. In contrast, distributed responses in prefrontal cortex are more strongly driven by task than category, and contain task-dependent category representations. Together, these findings of differential representations across the brain support a new idea that LOTC and VTC maintain stable category representations allowing efficient processing of visual information, while prefrontal cortex contains flexible representations in which category information may emerge only when relevant to the task. Copyright © 2017 Elsevier Inc. All rights reserved.

Increasing verbal knowledge mediates development of multidimensional emotion representations

PubMed Central

Nook, Erik C.; Sasse, Stephanie F.; Lambert, Hilary K.; McLaughlin, Katie A.; Somerville, Leah H.

2017-01-01

How do people represent their own and others’ emotional experiences? Contemporary emotion theories and growing evidence suggest that the conceptual representation of emotion plays a central role in how people understand the emotions both they and other people feel.1–6 Although decades of research indicate that adults typically represent emotion concepts as multidimensional, with valence (positive—negative) and arousal (activating—deactivating) as two primary dimensions,7–10 little is known about how this bidimensional (or circumplex) representation arises.11 Here we show that emotion representations develop from a monodimensional focus on valence to a bidimensional focus on both valence and arousal from age 6 to age 25. We investigated potential mechanisms underlying this effect and found that increasing verbal knowledge mediated emotion representation development over and above three other potential mediators: (i) fluid reasoning, (ii) the general ability to represent non-emotional stimuli bidimensionally, and (iii) task-related behaviors (e.g., using extreme ends of rating scales). These results suggest that verbal development facilitates the expansion of emotion concept representations (and potentially emotional experiences) from a “positive or negative” dichotomy in childhood to a multidimensional organization in adulthood. PMID:29399639

Ontology Design of Influential People Identification Using Centrality

NASA Astrophysics Data System (ADS)

Maulana Awangga, Rolly; Yusril, Muhammad; Setyawan, Helmi

2018-04-01

Identifying influential people as a node in a graph theory commonly calculated by social network analysis. The social network data has the user as node and edge as relation forming a friend relation graph. This research is conducting different meaning of every nodes relation in the social network. Ontology was perfect match science to describe the social network data as conceptual and domain. Ontology gives essential relationship in a social network more than a current graph. Ontology proposed as a standard for knowledge representation for the semantic web by World Wide Web Consortium. The formal data representation use Resource Description Framework (RDF) and Web Ontology Language (OWL) which is strategic for Open Knowledge-Based website data. Ontology used in the semantic description for a relationship in the social network, it is open to developing semantic based relationship ontology by adding and modifying various and different relationship to have influential people as a conclusion. This research proposes a model using OWL and RDF for influential people identification in the social network. The study use degree centrality, between ness centrality, and closeness centrality measurement for data validation. As a conclusion, influential people identification in Facebook can use proposed Ontology model in the Group, Photos, Photo Tag, Friends, Events and Works data.

[Multifaceted body. 2. The lived body].

PubMed

Wykretowicz, H; Saraga, M; Bourquin, C; Stiefel, F

2015-02-11

The human body is the object upon which medicine is acting, but also lived reality, image, symbol, representation and the object of elaboration and theory. All these elements which constitute the body influence the way medicine is treating it. In this series of three articles, we address the human body from various perspectives: medical (1), phenomenological (2), psychosomatic and socio-anthropological (3). This second article distinguishes between the body as an object of knowledge or representation and the way the body is lived. This distinction which originates in phenomenological psychiatry aims to understand how the patient experiences his body and to surpass the classical somatic and psychiatric classifications.

Spatial analysis of bus transport networks using network theory

NASA Astrophysics Data System (ADS)

Shanmukhappa, Tanuja; Ho, Ivan Wang-Hei; Tse, Chi Kong

2018-07-01

In this paper, we analyze the bus transport network (BTN) structure considering the spatial embedding of the network for three cities, namely, Hong Kong (HK), London (LD), and Bengaluru (BL). We propose a novel approach called supernode graph structuring for modeling the bus transport network. A static demand estimation procedure is proposed to assign the node weights by considering the points of interests (POIs) and the population distribution in the city over various localized zones. In addition, the end-to-end delay is proposed as a parameter to measure the topological efficiency of the bus networks instead of the shortest distance measure used in previous works. With the aid of supernode graph representation, important network parameters are analyzed for the directed, weighted and geo-referenced bus transport networks. It is observed that the supernode concept has significant advantage in analyzing the inherent topological behavior. For instance, the scale-free and small-world behavior becomes evident with supernode representation as compared to conventional or regular graph representation for the Hong Kong network. Significant improvement in clustering, reduction in path length, and increase in centrality values are observed in all the three networks with supernode representation. The correlation between topologically central nodes and the geographically central nodes reveals the interesting fact that the proposed static demand estimation method for assigning node weights aids in better identifying the geographically significant nodes in the network. The impact of these geographically significant nodes on the local traffic behavior is demonstrated by simulation using the SUMO (Simulation of Urban Mobility) tool which is also supported by real-world empirical data, and our results indicate that the traffic speed around a particular bus stop can reach a jammed state from a free flow state due to the presence of these geographically important nodes. A comparison of the simulation and the empirical data provides useful information on how bus operators can better plan their routes and deploy stops considering the geographically significant nodes.

What does semantic tiling of the cortex tell us about semantics?

PubMed

Barsalou, Lawrence W

2017-10-01

Recent use of voxel-wise modeling in cognitive neuroscience suggests that semantic maps tile the cortex. Although this impressive research establishes distributed cortical areas active during the conceptual processing that underlies semantics, it tells us little about the nature of this processing. While mapping concepts between Marr's computational and implementation levels to support neural encoding and decoding, this approach ignores Marr's algorithmic level, central for understanding the mechanisms that implement cognition, in general, and conceptual processing, in particular. Following decades of research in cognitive science and neuroscience, what do we know so far about the representation and processing mechanisms that implement conceptual abilities? Most basically, much is known about the mechanisms associated with: (1) feature and frame representations, (2) grounded, abstract, and linguistic representations, (3) knowledge-based inference, (4) concept composition, and (5) conceptual flexibility. Rather than explaining these fundamental representation and processing mechanisms, semantic tiles simply provide a trace of their activity over a relatively short time period within a specific learning context. Establishing the mechanisms that implement conceptual processing in the brain will require more than mapping it to cortical (and sub-cortical) activity, with process models from cognitive science likely to play central roles in specifying the intervening mechanisms. More generally, neuroscience will not achieve its basic goals until it establishes algorithmic-level mechanisms that contribute essential explanations to how the brain works, going beyond simply establishing the brain areas that respond to various task conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

The dual moral self: moral centrality and internal moral motivation.

PubMed

Krettenauer, Tobias

2011-01-01

In this study, the relationship between two aspects of the moral self, moral centrality and internal moral motivation, was analyzed. It is argued that these 2 aspects are conceptually distinct but nonetheless empirically related. Based on a cross-sectional study of 205 adolescents (M age = 14.83 years, SD = 2.21 years) it was found that moral centrality and internal moral motivation, even though substantially correlated, interacted in predicting moral emotion expectancies. Even though moral centrality was unrelated to adolescents' age it predicted a longitudinal increase in internal moral motivation over a 1-year interval. Overall, the findings call for a differentiation of moral centrality and internal moral motivation as 2 distinct but interrelated aspects of moral self-development that follow different developmental trajectories and are differentially related to age. At the same time, the study points out that adolescence may be less important for the development of the moral self than commonly assumed.

Beyond one-size-fits-all: Tailoring diversity approaches to the representation of social groups.

PubMed

Apfelbaum, Evan P; Stephens, Nicole M; Reagans, Ray E

2016-10-01

When and why do organizational diversity approaches that highlight the importance of social group differences (vs. equality) help stigmatized groups succeed? We theorize that social group members' numerical representation in an organization, compared with the majority group, influences concerns about their distinctiveness, and consequently, whether diversity approaches are effective. We combine laboratory and field methods to evaluate this theory in a professional setting, in which White women are moderately represented and Black individuals are represented in very small numbers. We expect that focusing on differences (vs. equality) will lead to greater performance and persistence among White women, yet less among Black individuals. First, we demonstrate that Black individuals report greater representation-based concerns than White women (Study 1). Next, we observe that tailoring diversity approaches to these concerns yields greater performance and persistence (Studies 2 and 3). We then manipulate social groups' perceived representation and find that highlighting differences (vs. equality) is more effective when groups' representation is moderate, but less effective when groups' representation is very low (Study 4). Finally, we content-code the diversity statements of 151 major U.S. law firms and find that firms that emphasize differences have lower attrition rates among White women, whereas firms that emphasize equality have lower attrition rates among racial minorities (Study 5). (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Conceptual and linguistic representations of kinds and classes

PubMed Central

Prasada, Sandeep; Hennefield, Laura; Otap, Daniel

2013-01-01

We investigate the hypothesis that our conceptual systems provide two formally distinct ways of representing categories by investigating the manner in which lexical nominals (e.g., tree, picnic table) and phrasal nominals (e.g., black bird, birds that like rice) are interpreted. Four experiments found that lexical nominals may be mapped onto kind representations whereas phrasal nominals map onto class representations but not kind representations. Experiment 1 found that phrasal nominals, unlike lexical nominals, are mapped onto categories whose members need not be of a single kind. Experiments 2 and 3 found that categories named by lexical nominals enter into both class inclusion and kind hierarchies and thus support both class inclusion (is a) and kind specification (kind of) relations, whereas phrasal nominals map onto class representations which support only class inclusion relations. Experiment 4 showed that the two types of nominals represent hierarchical relations in different ways. Phrasal nominals (e.g., white bear) are mapped onto classes that have criteria of membership in addition to those specified by the class picked out by the head noun of the phrase (e.g., bear). In contrast, lexical nominals (e.g., polar bear) specify one way to meet the criteria specified by the more general kind concept (e.g., bear). Implications for the language-conceptual system interface, representation of hierarchical relations, lexicalization, and theories of conceptual combination are discussed. PMID:22671567

Differential involvement of episodic and face representations in ERP repetition effects.

PubMed

Jemel, Boutheina; Calabria, Marco; Delvenne, Jean-François; Crommelinck, Marc; Bruyer, Raymond

2003-03-03

The purpose of this study was to disentangle the contribution of episodic-perceptual from pre-existing memory representations of faces to repetition effects. ERPs were recorded to first and second presentations of same and different photos of famous and unfamiliar faces, in an incidental task where occasional non-targets had to be detected. Repetition of same and different photos of famous faces resulted in an N400 amplitude decrement. No such N400 repetition-induced attenuation was observed for unfamiliar faces. In addition, repetition of same photos of faces, and not different ones, gave rise to an early ERP repetition effect (starting at approximately 350 ms) with an occipito-temporal scalp distribution. Together, these results suggest that repetition effects depend on two temporally and may be neuro-functionally distinct loci, episode-based representation and face recognition units stored in long-term memory.

Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization.

PubMed

Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan E B; Kastner, Sabine; Hasson, Uri

2015-02-19

The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas.

Distributed representations in memory: Insights from functional brain imaging

PubMed Central

Rissman, Jesse; Wagner, Anthony D.

2015-01-01

Forging new memories for facts and events, holding critical details in mind on a moment-to-moment basis, and retrieving knowledge in the service of current goals all depend on a complex interplay between neural ensembles throughout the brain. Over the past decade, researchers have increasingly leveraged powerful analytical tools (e.g., multi-voxel pattern analysis) to decode the information represented within distributed fMRI activity patterns. In this review, we discuss how these methods can sensitively index neural representations of perceptual and semantic content, and how leverage on the engagement of distributed representations provides unique insights into distinct aspects of memory-guided behavior. We emphasize that, in addition to characterizing the contents of memories, analyses of distributed patterns shed light on the processes that influence how information is encoded, maintained, or retrieved, and thus inform memory theory. We conclude by highlighting open questions about memory that can be addressed through distributed pattern analyses. PMID:21943171

The 2002 Sydney Gay Games: re-presenting "lesbian" identities through sporting space.

PubMed

Lambert, Karen

2009-01-01

In this article poetic representation in qualitative research is explored in relation to researching "lesbian" lives. Set within the context of The 2002 Sydney Gay Games the article considers how poetry can bring to light experiences at the intersection of sexuality, sport, and place. The article details three aspects to this process. First, by asking what queer theory could do for particular research subjects, a robust, malleable, and transportable theoretical concept of "queer" is proposed that is responsive to the participants' lives and experiences. Second, this concept is applied methodologically in order to unsettle more traditional academic modes of representing interview data through the use of poetic forms of representation. Finally, a poem constructed from the Opening Ceremony of The Gay Games is presented and analyzed. Poetic representation is thus offered as a distinct methodology that permits a particular kind of "queer" analysis when researching "lesbian" lives.

Impoverished descriptions of familiar routes in three cases of hippocampal/medial temporal lobe amnesia.

PubMed

Herdman, Katherine A; Calarco, Navona; Moscovitch, Morris; Hirshhorn, Marnie; Rosenbaum, R Shayna

2015-10-01

Recent research has challenged classic theories of hippocampal function in spatial memory with findings that the hippocampus may be necessary for detailed representations of environments learned long ago, but not for remembering the gist or schematic aspects that are sufficient for navigating within those environments (Rosenbaum et al., 2000; Rosenbaum, Winocur, Binns, & Moscovitch, 2012). We aimed to probe further distinctions between detailed and schematic representations of familiar environments in three cases of hippocampal/medial temporal lobe (MTL) amnesia by testing them on a route description task and mental navigation tasks that assess the identity and location of landmarks, and distances and directions between them. The amnesic cases could describe basic directions along known, imagined routes, estimate distance and direction between well-known landmarks, and produce sketch maps with accurate layouts, suggestive of intact schematic representations. However, findings that their route descriptions lack richness of detail, along with impoverished sketch maps and poor landmark recognition, substantiates previous findings that detailed representations are hippocampus-dependent. Copyright © 2015 Elsevier Ltd. All rights reserved.

The neural representation of objects formed through the spatiotemporal integration of visual transients

PubMed Central

Erlikhman, Gennady; Gurariy, Gennadiy; Mruczek, Ryan E.B.; Caplovitz, Gideon P.

2016-01-01

Oftentimes, objects are only partially and transiently visible as parts of them become occluded during observer or object motion. The visual system can integrate such object fragments across space and time into perceptual wholes or spatiotemporal objects. This integrative and dynamic process may involve both ventral and dorsal visual processing pathways, along which shape and spatial representations are thought to arise. We measured fMRI BOLD response to spatiotemporal objects and used multi-voxel pattern analysis (MVPA) to decode shape information across 20 topographic regions of visual cortex. Object identity could be decoded throughout visual cortex, including intermediate (V3A, V3B, hV4, LO1-2,) and dorsal (TO1-2, and IPS0-1) visual areas. Shape-specific information, therefore, may not be limited to early and ventral visual areas, particularly when it is dynamic and must be integrated. Contrary to the classic view that the representation of objects is the purview of the ventral stream, intermediate and dorsal areas may play a distinct and critical role in the construction of object representations across space and time. PMID:27033688

Insight into others' minds: spatio-temporal representations by intrinsic frame of reference.

PubMed

Sun, Yanlong; Wang, Hongbin

2014-01-01

Recent research has seen a growing interest in connections between domains of spatial and social cognition. Much evidence indicates that processes of representing space in distinct frames of reference (FOR) contribute to basic spatial abilities as well as sophisticated social abilities such as tracking other's intention and belief. Argument remains, however, that belief reasoning in social domain requires an innately dedicated system and cannot be reduced to low-level encoding of spatial relationships. Here we offer an integrated account advocating the critical roles of spatial representations in intrinsic frame of reference. By re-examining the results from a spatial task (Tamborello etal., 2012) and a false-belief task (Onishi and Baillargeon, 2005), we argue that spatial and social abilities share a common origin at the level of spatio-temporal association and predictive learning, where multiple FOR-based representations provide the basic building blocks for efficient and flexible partitioning of the environmental statistics. We also discuss neuroscience evidence supporting these mechanisms. We conclude that FOR-based representations may bridge the conceptual as well as the implementation gaps between the burgeoning fields of social and spatial cognition.

The Cognitive Advantages of Counting Specifically: A Representational Analysis of Verbal Numeration Systems in Oceanic Languages.

PubMed

Bender, Andrea; Schlimm, Dirk; Beller, Sieghard

2015-10-01

The domain of numbers provides a paradigmatic case for investigating interactions of culture, language, and cognition: Numerical competencies are considered a core domain of knowledge, and yet the development of specifically human abilities presupposes cultural and linguistic input by way of counting sequences. These sequences constitute systems with distinct structural properties, the cross-linguistic variability of which has implications for number representation and processing. Such representational effects are scrutinized for two types of verbal numeration systems-general and object-specific ones-that were in parallel use in several Oceanic languages (English with its general system is included for comparison). The analysis indicates that the object-specific systems outperform the general systems with respect to counting and mental arithmetic, largely due to their regular and more compact representation. What these findings reveal on cognitive diversity, how the conjectures involved speak to more general issues in cognitive science, and how the approach taken here might help to bridge the gap between anthropology and other cognitive sciences is discussed in the conclusion. Copyright © 2015 Cognitive Science Society, Inc.

Infrared small target detection in heavy sky scene clutter based on sparse representation

NASA Astrophysics Data System (ADS)

Liu, Depeng; Li, Zhengzhou; Liu, Bing; Chen, Wenhao; Liu, Tianmei; Cao, Lei

2017-09-01

A novel infrared small target detection method based on sky clutter and target sparse representation is proposed in this paper to cope with the representing uncertainty of clutter and target. The sky scene background clutter is described by fractal random field, and it is perceived and eliminated via the sparse representation on fractal background over-complete dictionary (FBOD). The infrared small target signal is simulated by generalized Gaussian intensity model, and it is expressed by the generalized Gaussian target over-complete dictionary (GGTOD), which could describe small target more efficiently than traditional structured dictionaries. Infrared image is decomposed on the union of FBOD and GGTOD, and the sparse representation energy that target signal and background clutter decomposed on GGTOD differ so distinctly that it is adopted to distinguish target from clutter. Some experiments are induced and the experimental results show that the proposed approach could improve the small target detection performance especially under heavy clutter for background clutter could be efficiently perceived and suppressed by FBOD and the changing target could also be represented accurately by GGTOD.

Emergent categorical representation of natural, complex sounds resulting from the early post-natal sound environment

PubMed Central

Bao, Shaowen; Chang, Edward F.; Teng, Ching-Ling; Heiser, Marc A.; Merzenich, Michael M.

2013-01-01

Cortical sensory representations can be reorganized by sensory exposure in an epoch of early development. The adaptive role of this type of plasticity for natural sounds in sensory development is, however, unclear. We have reared rats in a naturalistic, complex acoustic environment and examined their auditory representations. We found that cortical neurons became more selective to spectrotemporal features in the experienced sounds. At the neuronal population level, more neurons were involved in representing the whole set of complex sounds, but fewer neurons actually responded to each individual sound, but with greater magnitudes. A comparison of population-temporal responses to the experienced complex sounds revealed that cortical responses to different renderings of the same song motif were more similar, indicating that the cortical neurons became less sensitive to natural acoustic variations associated with stimulus context and sound renderings. By contrast, cortical responses to sounds of different motifs became more distinctive, suggesting that cortical neurons were tuned to the defining features of the experienced sounds. These effects lead to emergent “categorical” representations of the experienced sounds, which presumably facilitate their recognition. PMID:23747304

Structure-guided statistical textural distinctiveness for salient region detection in natural images.

PubMed

Scharfenberger, Christian; Wong, Alexander; Clausi, David A

2015-01-01

We propose a simple yet effective structure-guided statistical textural distinctiveness approach to salient region detection. Our method uses a multilayer approach to analyze the structural and textural characteristics of natural images as important features for salient region detection from a scale point of view. To represent the structural characteristics, we abstract the image using structured image elements and extract rotational-invariant neighborhood-based textural representations to characterize each element by an individual texture pattern. We then learn a set of representative texture atoms for sparse texture modeling and construct a statistical textural distinctiveness matrix to determine the distinctiveness between all representative texture atom pairs in each layer. Finally, we determine saliency maps for each layer based on the occurrence probability of the texture atoms and their respective statistical textural distinctiveness and fuse them to compute a final saliency map. Experimental results using four public data sets and a variety of performance evaluation metrics show that our approach provides promising results when compared with existing salient region detection approaches.

Quantum spaces, central extensions of Lie groups and related quantum field theories

NASA Astrophysics Data System (ADS)

Poulain, Timothé; Wallet, Jean-Christophe

2018-02-01

Quantum spaces with su(2) noncommutativity can be modelled by using a family of SO(3)-equivariant differential *-representations. The quantization maps are determined from the combination of the Wigner theorem for SU(2) with the polar decomposition of the quantized plane waves. A tracial star-product, equivalent to the Kontsevich product for the Poisson manifold dual to su(2) is obtained from a subfamily of differential *-representations. Noncommutative (scalar) field theories free from UV/IR mixing and whose commutative limit coincides with the usual ϕ 4 theory on ℛ3 are presented. A generalization of the construction to semi-simple possibly non simply connected Lie groups based on their central extensions by suitable abelian Lie groups is discussed. Based on a talk presented by Poulain T at the XXVth International Conference on Integrable Systems and Quantum symmetries (ISQS-25), Prague, June 6-10 2017.

Structure and Evolution of the Foreign Exchange Networks

NASA Astrophysics Data System (ADS)

Kwapień, J.; Gworek, S.; Drożdż, S.

2009-01-01

We investigate topology and temporal evolution of the foreign currency exchange market viewed from a weighted network perspective. Based on exchange rates for a set of 46 currencies (including precious metals), we construct different representations of the FX network depending on a choice of the base currency. Our results show that the network structure is not stable in time, but there are main clusters of currencies, which persist for a long period of time despite the fact that their size and content are variable. We find a long-term trend in the network's evolution which affects the USD and EUR nodes. In all the network representations, the USD node gradually loses its centrality, while, on contrary, the EUR node has become slightly more central than it used to be in its early years. Despite this directional trend, the overall evolution of the network is noisy.

The construction of tridimensional representation of body and external reality in man. The greatest achievement of evolution to date implications for virtual reality.

PubMed

Woodbury, M A; Woodbury, M F

1998-01-01

Our 3-D Body Representation constructed during development by our Central Nervous System under the direction of our DNA, consists of a holographic representation arising from sensory input in the cerebellum and projected extraneurally in the brain ventricular fluid which has the chemical structure of liquid crystal. The structure of 3-D holographic Body Representation is then extrapolated by such cognitive instruments as boundarization, geometrization and gestalt organization upon the external environment which is perceived consequently as three dimensional. When the Body Representation collapses as in psychotic panic states. patients become terrified as they suddenly lose the perception of themselves and the world around them as three dimensional, solid in a reliably solid environment but feel suddenly that they are no longer a person but a disorganized blob. In our clinical practice we found serendipitously that the structure of three dimensionality can be restored even without medication by techniques involving stimulation of the body sensory system in the presence of a benevolent psychotherapist. Implications for Virtual Reality will be discussed.

Representing time in language and memory: the role of similarity structure.

PubMed

Faber, Myrthe; Gennari, Silvia P

2015-03-01

Every day we read about or watch events in the world and can easily understand or remember how long they last. What aspects of an event are retained in memory? And how do we extract temporal information from our memory representations? These issues are central to human cognition, as they underlie a fundamental aspect of our mental life, namely our representation of time. This paper reviews previous language studies and reports a visual learning study indicating that properties of the events encoded in memory shape the representation of their duration. The evidence indicates that for a given event, the extent to which its associated properties or sub-components differ from one another modulates our representation of its duration. These properties include the similarity between sub-events and the similarity between the situational contexts in which an event occurs. We suggest that the diversity of representations that we associate with events in memory plays an important role in remembering and estimating the duration of experienced or described events. Copyright © 2014 Elsevier B.V. All rights reserved.

Inference and Association in Children's Early Numerical Estimation

ERIC Educational Resources Information Center

Sullivan, Jessica; Barner, David

2014-01-01

How do children map number words to the numerical magnitudes they represent? Recent work in adults has shown that two distinct mechanisms--structure mapping and associative mapping--connect number words to nonlinguistic numerical representations (Sullivan, J., 2012). This study investigated the development of number word mappings, and the roles of…

Round Girls in Square Computers: Feminist Perspectives on the Aesthetics of Computer Hardware.

ERIC Educational Resources Information Center

Carr-Chellman, Alison A.; Marra, Rose M.; Roberts, Shari L.

2002-01-01

Considers issues related to computer hardware, aesthetics, and gender. Explores how gender has influenced the design of computer hardware and how these gender-driven aesthetics may have worked to maintain, extend, or alter gender distinctions, roles, and stereotypes; discusses masculine media representations; and presents an alternative model.…

The Role of Aging in Intra-Item and Item-Context Binding Processes in Visual Working Memory

ERIC Educational Resources Information Center

Peterson, Dwight J.; Naveh-Benjamin, Moshe

2016-01-01

Aging is accompanied by declines in both working memory and long-term episodic memory processes. Specifically, important age-related memory deficits are characterized by performance impairments exhibited by older relative to younger adults when binding distinct components into a single integrated representation, despite relatively intact memory…

The Acquisition of SV Order in Unaccusatives: Manipulating the Definiteness of the NP Argument

ERIC Educational Resources Information Center

Vernice, Mirta; Guasti, Maria Teresa

2015-01-01

In two sentence repetition experiments, we investigated whether four- and five-year-olds master distinct representations for intransitive verb classes by testing two syntactic analyses of unaccusatives (Burzio, 1986; Belletti, 1988). Under the assumption that, with unaccusatives, the partitive case of the postverbal argument is realized only on…

Brain responses to social norms: Meta-analyses of fMRI studies.

PubMed

Zinchenko, Oksana; Arsalidou, Marie

2018-02-01

Social norms have a critical role in everyday decision-making, as frequent interaction with others regulates our behavior. Neuroimaging studies show that social-based and fairness-related decision-making activates an inconsistent set of areas, which sometimes includes the anterior insula, anterior cingulate cortex, and others lateral prefrontal cortices. Social-based decision-making is complex and variability in findings may be driven by socio-cognitive activities related to social norms. To distinguish among social-cognitive activities related to social norms, we identified 36 eligible articles in the functional magnetic resonance imaging (fMRI) literature, which we separate into two categories (a) social norm representation and (b) norm violations. The majority of original articles (>60%) used tasks associated with fairness norms and decision-making, such as ultimatum game, dictator game, or prisoner's dilemma; the rest used tasks associated to violation of moral norms, such as scenarios and sentences of moral depravity ratings. Using quantitative meta-analyses, we report common and distinct brain areas that show concordance as a function of category. Specifically, concordance in ventromedial prefrontal regions is distinct to social norm representation processing, whereas concordance in right insula, dorsolateral prefrontal, and dorsal cingulate cortices is distinct to norm violation processing. We propose a neurocognitive model of social norms for healthy adults, which could help guide future research in social norm compliance and mechanisms of its enforcement. © 2017 Wiley Periodicals, Inc.

Adjudicating between face-coding models with individual-face fMRI responses

PubMed Central

Kriegeskorte, Nikolaus

2017-01-01

The perceptual representation of individual faces is often explained with reference to a norm-based face space. In such spaces, individuals are encoded as vectors where identity is primarily conveyed by direction and distinctiveness by eccentricity. Here we measured human fMRI responses and psychophysical similarity judgments of individual face exemplars, which were generated as realistic 3D animations using a computer-graphics model. We developed and evaluated multiple neurobiologically plausible computational models, each of which predicts a representational distance matrix and a regional-mean activation profile for 24 face stimuli. In the fusiform face area, a face-space coding model with sigmoidal ramp tuning provided a better account of the data than one based on exemplar tuning. However, an image-processing model with weighted banks of Gabor filters performed similarly. Accounting for the data required the inclusion of a measurement-level population averaging mechanism that approximates how fMRI voxels locally average distinct neuronal tunings. Our study demonstrates the importance of comparing multiple models and of modeling the measurement process in computational neuroimaging. PMID:28746335

Memory Systems Do Not Divide on Consciousness: Reinterpreting Memory in Terms of Activation and Binding

PubMed Central

Reder, Lynne M.; Park, Heekyeong; Kieffaber, Paul D.

2009-01-01

There is a popular hypothesis that performance on implicit and explicit memory tasks reflects 2 distinct memory systems. Explicit memory is said to store those experiences that can be consciously recollected, and implicit memory is said to store experiences and affect subsequent behavior but to be unavailable to conscious awareness. Although this division based on awareness is a useful taxonomy for memory tasks, the authors review the evidence that the unconscious character of implicit memory does not necessitate that it be treated as a separate system of human memory. They also argue that some implicit and explicit memory tasks share the same memory representations and that the important distinction is whether the task (implicit or explicit) requires the formation of a new association. The authors review and critique dissociations from the behavioral, amnesia, and neuroimaging literatures that have been advanced in support of separate explicit and implicit memory systems by highlighting contradictory evidence and by illustrating how the data can be accounted for using a simple computational memory model that assumes the same memory representation for those disparate tasks. PMID:19210052

Distinct representations of configural and part information across multiple face-selective regions of the human brain

PubMed Central

Golarai, Golijeh; Ghahremani, Dara G.; Eberhardt, Jennifer L.; Gabrieli, John D. E.

2015-01-01

Several regions of the human brain respond more strongly to faces than to other visual stimuli, such as regions in the amygdala (AMG), superior temporal sulcus (STS), and the fusiform face area (FFA). It is unclear if these brain regions are similar in representing the configuration or natural appearance of face parts. We used functional magnetic resonance imaging of healthy adults who viewed natural or schematic faces with internal parts that were either normally configured or randomly rearranged. Response amplitudes were reduced in the AMG and STS when subjects viewed stimuli whose configuration of parts were digitally rearranged, suggesting that these regions represent the 1st order configuration of face parts. In contrast, response amplitudes in the FFA showed little modulation whether face parts were rearranged or if the natural face parts were replaced with lines. Instead, FFA responses were reduced only when both configural and part information were reduced, revealing an interaction between these factors, suggesting distinct representation of 1st order face configuration and parts in the AMG and STS vs. the FFA. PMID:26594191

Core geometry in perspective

PubMed Central

Dillon, Moira R.; Spelke, Elizabeth S.

2015-01-01

Research on animals, infants, children, and adults provides evidence that distinct cognitive systems underlie navigation and object recognition. Here we examine whether and how these systems interact when children interpret 2D edge-based perspectival line drawings of scenes and objects. Such drawings serve as symbols early in development, and they preserve scene and object geometry from canonical points of view. Young children show limits when using geometry both in non-symbolic tasks and in symbolic map tasks that present 3D contexts from unusual, unfamiliar points of view. When presented with the familiar viewpoints in perspectival line drawings, however, do children engage more integrated geometric representations? In three experiments, children successfully interpreted line drawings with respect to their depicted scene or object. Nevertheless, children recruited distinct processes when navigating based on the information in these drawings, and these processes depended on the context in which the drawings were presented. These results suggest that children are flexible but limited in using geometric information to form integrated representations of scenes and objects, even when interpreting spatial symbols that are highly familiar and faithful renditions of the visual world. PMID:25441089

Music and language expertise influence the categorization of speech and musical sounds: behavioral and electrophysiological measurements.

PubMed

Elmer, Stefan; Klein, Carina; Kühnis, Jürg; Liem, Franziskus; Meyer, Martin; Jäncke, Lutz

2014-10-01

In this study, we used high-density EEG to evaluate whether speech and music expertise has an influence on the categorization of expertise-related and unrelated sounds. With this purpose in mind, we compared the categorization of speech, music, and neutral sounds between professional musicians, simultaneous interpreters (SIs), and controls in response to morphed speech-noise, music-noise, and speech-music continua. Our hypothesis was that music and language expertise will strengthen the memory representations of prototypical sounds, which act as a perceptual magnet for morphed variants. This means that the prototype would "attract" variants. This so-called magnet effect should be manifested by an increased assignment of morphed items to the trained category, by a reduced maximal slope of the psychometric function, as well as by differential event-related brain responses reflecting memory comparison processes (i.e., N400 and P600 responses). As a main result, we provide first evidence for a domain-specific behavioral bias of musicians and SIs toward the trained categories, namely music and speech. In addition, SIs showed a bias toward musical items, indicating that interpreting training has a generic influence on the cognitive representation of spectrotemporal signals with similar acoustic properties to speech sounds. Notably, EEG measurements revealed clear distinct N400 and P600 responses to both prototypical and ambiguous items between the three groups at anterior, central, and posterior scalp sites. These differential N400 and P600 responses represent synchronous activity occurring across widely distributed brain networks, and indicate a dynamical recruitment of memory processes that vary as a function of training and expertise.

Optical dissection of odor information processing in vivo using GCaMPs expressed in specified cell types of the olfactory bulb

PubMed Central

Wachowiak, Matt; Economo, Michael N.; Díaz-Quesada, Marta; Brunert, Daniela; Wesson, Daniel W.; White, John. A.; Rothermel, Markus

2013-01-01

Understanding central processing requires precise monitoring of neural activity across populations of identified neurons in the intact brain. Here we used recently-optimized variants of the genetically-encoded calcium sensor GCaMP (GCaMP3 and GCaMPG5G) to image activity among genetically- and anatomically-defined neuronal populations in the olfactory bulb (OB), including two types of GABA-ergic interneurons (periglomerular (PG) and short axon (SA) cells) and OB output neurons (mitral/tufted (MT) cells) projecting to piriform cortex. We first established that changes in neuronal spiking can be accurately related to GCaMP fluorescence changes via a simple quantitative relationship over a large dynamic range. We next used in vivo two-photon imaging from individual neurons and epifluorescence signals reflecting population-level activity to investigate the spatiotemporal representation of odorants across these neuron types in anesthetized and awake mice. Under anesthesia, individual PG and SA cells showed temporally simple responses and little spontaneous activity, while MT cells were spontaneously active and showed diverse temporal responses. At the population level, response patterns of PG, SA and MT cells were surprisingly similar to those imaged from sensory inputs, with shared odorant-specific topography across the dorsal OB and inhalation-coupled temporal dynamics. During wakefulness, PG and SA cell responses increased in magnitude but remained temporally simple while those of MT cells changed to complex spatiotemporal patterns reflecting restricted excitation and widespread inhibition. These results point to multiple circuit elements with distinct roles in transforming odor representations in the OB and provide a framework for further dissecting early olfactory processing using optical and genetic tools. PMID:23516293

Locality, reflection, and wave-particle duality

NASA Astrophysics Data System (ADS)

Mugur-Schächter, Mioara

1987-08-01

Bell's theorem is believed to establish that the quantum mechanical predictions do not generally admit a causal representation compatible with Einsten's principle of separability, thereby proving incompatibility between quantum mechanics and relativity. This interpretation is contested via two convergent approaches which lead to a sharp distinction between quantum nonseparability and violation of Einstein's theory of relativity. In a first approach we explicate from the quantum mechanical formalism a concept of “reflected dependence.” Founded on this concept, we produce a causal representation of the quantum mechanical probability measure involved in Bell's proof, which is clearly separable in Einstein's sense, i.e., it does not involve supraluminal velocities, and nevertheless is “nonlocal” in Bell's sense. So Bell locality and Einstein separability are distinct qualifications, and Bell nonlocality (or Bell nonseparability) and Einstein separability are not incompatible. It is then proved explicitly that with respect to the mentioned representation Bell's derivation does not hold. So Bell's derivation does not establish that any Einstein-separable representation is incompatible with quantum mechanics. This first—negative—conclusion is a syntactic fact. The characteristics of the representation and of the reasoning involved in the mentioned counterexample to the usual interpretation of Bell's theorem suggest that the representation used—notwithstanding its ability to bring forth the specified syntactic fact—is not factually true. Factual truth and syntactic properties also have to be radically distinguished in their turn. So, in a second approach, starting from de Broglie's initial relativistic model of a microsystem, a deeper, factually acceptable representation is constructed. The analyses leading to this second representation show that quantum mechanics does indeed involve basically a certain sort of nonseparability, called here de Broglie-Bohr quantum nonseparability. But the de Broglie-Bohr quantum nonseparability is shown to stem directly from the relativistic character of the considerations which led Louis de Broglie to the fundamental relation p = h/λ, thereby being essentially consistent with relativity. As to Einstein separability, it appears to be a still insufficiently specified concept of which a future, improved specification, will probably be explicitly harmonizable with the de Broglie-Bohr quantum nonseparability. The ensemble of the conclusions obtained here brings forth a new concept of causality, a concept of folded, zigzag, reflexive causality, with respect to which the type of causality conceived of up to now appears as a particular case of outstretched, one-way causality. The reflexive causality is found compatible with the results of Aspect's experiment, and it suggests new experiments. Considered globally, the conclusions obtained in the present work might convert the conceptual situation created by Bell's proof into a process of unification of quantum mechanics and relativity.

Dopaminergic control of motivation and reinforcement learning: a closed-circuit account for reward-oriented behavior.

PubMed

Morita, Kenji; Morishima, Mieko; Sakai, Katsuyuki; Kawaguchi, Yasuo

2013-05-15

Humans and animals take actions quickly when they expect that the actions lead to reward, reflecting their motivation. Injection of dopamine receptor antagonists into the striatum has been shown to slow such reward-seeking behavior, suggesting that dopamine is involved in the control of motivational processes. Meanwhile, neurophysiological studies have revealed that phasic response of dopamine neurons appears to represent reward prediction error, indicating that dopamine plays central roles in reinforcement learning. However, previous attempts to elucidate the mechanisms of these dopaminergic controls have not fully explained how the motivational and learning aspects are related and whether they can be understood by the way the activity of dopamine neurons itself is controlled by their upstream circuitries. To address this issue, we constructed a closed-circuit model of the corticobasal ganglia system based on recent findings regarding intracortical and corticostriatal circuit architectures. Simulations show that the model could reproduce the observed distinct motivational effects of D1- and D2-type dopamine receptor antagonists. Simultaneously, our model successfully explains the dopaminergic representation of reward prediction error as observed in behaving animals during learning tasks and could also explain distinct choice biases induced by optogenetic stimulation of the D1 and D2 receptor-expressing striatal neurons. These results indicate that the suggested roles of dopamine in motivational control and reinforcement learning can be understood in a unified manner through a notion that the indirect pathway of the basal ganglia represents the value of states/actions at a previous time point, an empirically driven key assumption of our model.

Bio-SimVerb and Bio-SimLex: wide-coverage evaluation sets of word similarity in biomedicine.

PubMed

Chiu, Billy; Pyysalo, Sampo; Vulić, Ivan; Korhonen, Anna

2018-02-05

Word representations support a variety of Natural Language Processing (NLP) tasks. The quality of these representations is typically assessed by comparing the distances in the induced vector spaces against human similarity judgements. Whereas comprehensive evaluation resources have recently been developed for the general domain, similar resources for biomedicine currently suffer from the lack of coverage, both in terms of word types included and with respect to the semantic distinctions. Notably, verbs have been excluded, although they are essential for the interpretation of biomedical language. Further, current resources do not discern between semantic similarity and semantic relatedness, although this has been proven as an important predictor of the usefulness of word representations and their performance in downstream applications. We present two novel comprehensive resources targeting the evaluation of word representations in biomedicine. These resources, Bio-SimVerb and Bio-SimLex, address the previously mentioned problems, and can be used for evaluations of verb and noun representations respectively. In our experiments, we have computed the Pearson's correlation between performances on intrinsic and extrinsic tasks using twelve popular state-of-the-art representation models (e.g. word2vec models). The intrinsic-extrinsic correlations using our datasets are notably higher than with previous intrinsic evaluation benchmarks such as UMNSRS and MayoSRS. In addition, when evaluating representation models for their abilities to capture verb and noun semantics individually, we show a considerable variation between performances across all models. Bio-SimVerb and Bio-SimLex enable intrinsic evaluation of word representations. This evaluation can serve as a predictor of performance on various downstream tasks in the biomedical domain. The results on Bio-SimVerb and Bio-SimLex using standard word representation models highlight the importance of developing dedicated evaluation resources for NLP in biomedicine for particular word classes (e.g. verbs). These are needed to identify the most accurate methods for learning class-specific representations. Bio-SimVerb and Bio-SimLex are publicly available.

Standardized Fault-Tolerant Sensing Nodes for an Intelligent Turbine Engine Control System (Preprint)

DTIC Science & Technology

2013-05-01

representation of a centralized control system on a turbine engine. All actuators and sensors are point-to-point cabled to the controller ( FADEC ) which...electronics themselves. Figure 1: Centralized Control System Each function resides within the FADEC and uses Unique Point-to-Point Analog...distributed control system on the same turbine engine. The actuators and sensors interface to Smart Nodes which, in turn communicate to the FADEC via

Semantic memory influences episodic retrieval by increased familiarity.

PubMed

Wang, Yujuan; Mao, Xinrui; Li, Bingcan; Lu, Baoqing; Guo, Chunyan

2016-07-06

The role of familiarity in associative recognition has been investigated in a number of studies, which have indicated that familiarity can facilitate recognition under certain circumstances. The ability of a pre-experimentally existing common representation to boost the contribution of familiarity has rarely been investigated. In addition, although many studies have investigated the interactions between semantic memory and episodic retrieval, the conditions that influence the presence of specific patterns were unclear. This study aimed to address these two questions. We manipulated the degree of overlap between the two representations using synonym and nonsynonym pairs in an associative recognition task. Results indicated that an increased degree of overlap enhanced recognition performance. The analysis of event-related potentials effects in the test phase showed that synonym pairs elicited both types of old/rearranged effects, whereas nonsynonym pairs elicited a late old/rearranged effect. These results confirmed that a common representation, irrespective of source, was necessary for assuring the presence of familiarity, but a common representation could not distinguish associative recognition depending on familiarity alone. Moreover, our expected double dissociation between familiarity and recollection was absent, which indicated that mode selection may be influenced by the degree of distinctness between old and rearranged pairs rather than the degree of overlap between representations.

Process and representation in graphical displays

NASA Technical Reports Server (NTRS)

Gillan, Douglas J.; Lewis, Robert; Rudisill, Marianne

1990-01-01

How people comprehend graphics is examined. Graphical comprehension involves the cognitive representation of information from a graphic display and the processing strategies that people apply to answer questions about graphics. Research on representation has examined both the features present in a graphic display and the cognitive representation of the graphic. The key features include the physical components of a graph, the relation between the figure and its axes, and the information in the graph. Tests of people's memory for graphs indicate that both the physical and informational aspect of a graph are important in the cognitive representation of a graph. However, the physical (or perceptual) features overshadow the information to a large degree. Processing strategies also involve a perception-information distinction. In order to answer simple questions (e.g., determining the value of a variable, comparing several variables, and determining the mean of a set of variables), people switch between two information processing strategies: (1) an arithmetic, look-up strategy in which they use a graph much like a table, looking up values and performing arithmetic calculations; and (2) a perceptual strategy in which they use the spatial characteristics of the graph to make comparisons and estimations. The user's choice of strategies depends on the task and the characteristics of the graph. A theory of graphic comprehension is presented.

Common sense of experts: Social representations of justice amongst professionals.

PubMed

Rochira, Alessia

2014-09-01

The dialectics between different modes of knowledge is at the very core of social sciences. In particular, the theory of social representations looks at expert and lay modes as they were not peculiar of specific domains but rather as they were mutually interdependent. Based on the conceptual distinction between reified and consensual universes, this article explores the interplay between these two sources of knowledge through the analysis of the social representations of justice produced by justice professionals. In particular, the exploration of the social representations of justice amongst experts offers intriguing clues to overtake the idea that the lay understanding of justice is somehow opposed to the expert viewpoint and to accept the polyphasic understanding of this complex object. The article reports the findings of a qualitative investigation of the social representations of justice amongst professionals. The staff members of the Youth Social Services (YSS) and the Juvenile Classification Home and Residential Community (JCHRC) were interviewed, and transcriptions were content analysed. The findings indicated that professionals generate multiple theories of justice with each presenting a particular articulation of the basic interplay between expert and lay viewpoints. Most important, findings indicate that the context of everyday working practice has a significant symbolic valence that goes beyond the boundaries of the reified context of institutional justice system.

Towards an understanding of the mechanisms of weak central coherence effects: experiments in visual configural learning and auditory perception.

PubMed Central

Plaisted, Kate; Saksida, Lisa; Alcántara, José; Weisblatt, Emma

2003-01-01

The weak central coherence hypothesis of Frith is one of the most prominent theories concerning the abnormal performance of individuals with autism on tasks that involve local and global processing. Individuals with autism often outperform matched nonautistic individuals on tasks in which success depends upon processing of local features, and underperform on tasks that require global processing. We review those studies that have been unable to identify the locus of the mechanisms that may be responsible for weak central coherence effects and those that show that local processing is enhanced in autism but not at the expense of global processing. In the light of these studies, we propose that the mechanisms which can give rise to 'weak central coherence' effects may be perceptual. More specifically, we propose that perception operates to enhance the representation of individual perceptual features but that this does not impact adversely on representations that involve integration of features. This proposal was supported in the two experiments we report on configural and feature discrimination learning in high-functioning children with autism. We also examined processes of perception directly, in an auditory filtering task which measured the width of auditory filters in individuals with autism and found that the width of auditory filters in autism were abnormally broad. We consider the implications of these findings for perceptual theories of the mechanisms underpinning weak central coherence effects. PMID:12639334

Beyond Capacity Limitations: Determinants of Word Recall Performance on Verbal Working Memory Span Tasks in Children With SLI

PubMed Central

Mainela-Arnold, Elina; Evans, Julia L.

2016-01-01

Reduced verbal working memory capacity has been proposed as a possible account of language impairments in specific language impairment (SLI). Studies have shown, however, that differences in strength of linguistic representations in the form of word frequency affect list recall and performance on verbal working memory tasks. This suggests that verbal memory capacity and long-term linguistic knowledge may not be distinct constructs. It has been suggested that linguistic representations in SLI are weak in ways that result in a breakdown in language processing on tasks that require manipulation of unfamiliar material. In this study, the effects of word frequency, long-term linguistic knowledge, and serial order position on recall performance in the competing language processing task (CLPT) were investigated in 10 children with SLI and 10 age-matched peers (age 8 years 6 months to 12 years 4 months). The children with SLI recalled significantly fewer target words on the CLPT as compared with their age-matched controls. The SLI group did not differ, however, in their ability to recall target words having high word frequency but were significantly poorer in their ability to recall words on the CLPT having low word frequency. Differences in receptive and expressive language abilities also appeared closely related to performance on the CLPT, suggesting that working memory capacity is not distinct from language knowledge and that degraded linguistic representations may have an effect on performance on verbal working memory span tasks in children with SLI. PMID:16378481

Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa.

PubMed

Bertola, Laura D; Tensen, Laura; van Hooft, Pim; White, Paula A; Driscoll, Carlos A; Henschel, Philipp; Caragiulo, Anthony; Dias-Freedman, Isabela; Sogbohossou, Etotépé A; Tumenta, Pricelia N; Jirmo, Tuqa H; de Snoo, Geert R; de Iongh, Hans H; Vrieling, Klaas

2015-01-01

The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted.

Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa

PubMed Central

Bertola, Laura D.; Tensen, Laura; van Hooft, Pim; White, Paula A.; Driscoll, Carlos A.; Henschel, Philipp; Caragiulo, Anthony; Dias-Freedman, Isabela; Sogbohossou, Etotépé A.; Tumenta, Pricelia N.; Jirmo, Tuqa H.; de Snoo, Geert R.

2015-01-01

The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted. PMID:26466139

48 CFR 19.308 - Protesting a firm's status as an economically disadvantaged women-owned small business (EDWOSB...

Code of Federal Regulations, 2012 CFR

2012-10-01

... Central Contractor Registration (CCR) and Online Representations and Certifications Application (ORCA) as... decision. (iv) The concern must remove its designation in CCR and ORCA as an EDWOSB or WOSB concern...

Information retrieval algorithms: A survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raghavan, P.

We give an overview of some algorithmic problems arising in the representation of text/image/multimedia objects in a form amenable to automated searching, and in conducting these searches efficiently. These operations are central to information retrieval and digital library systems.

Phase locked neural activity in the human brainstem predicts preference for musical consonance.

PubMed

Bones, Oliver; Hopkins, Kathryn; Krishnan, Ananthanarayan; Plack, Christopher J

2014-05-01

When musical notes are combined to make a chord, the closeness of fit of the combined spectrum to a single harmonic series (the 'harmonicity' of the chord) predicts the perceived consonance (how pleasant and stable the chord sounds; McDermott, Lehr, & Oxenham, 2010). The distinction between consonance and dissonance is central to Western musical form. Harmonicity is represented in the temporal firing patterns of populations of brainstem neurons. The current study investigates the role of brainstem temporal coding of harmonicity in the perception of consonance. Individual preference for consonant over dissonant chords was measured using a rating scale for pairs of simultaneous notes. In order to investigate the effects of cochlear interactions, notes were presented in two ways: both notes to both ears or each note to different ears. The electrophysiological frequency following response (FFR), reflecting sustained neural activity in the brainstem synchronised to the stimulus, was also measured. When both notes were presented to both ears the perceptual distinction between consonant and dissonant chords was stronger than when the notes were presented to different ears. In the condition in which both notes were presented to the both ears additional low-frequency components, corresponding to difference tones resulting from nonlinear cochlear processing, were observable in the FFR effectively enhancing the neural harmonicity of consonant chords but not dissonant chords. Suppressing the cochlear envelope component of the FFR also suppressed the additional frequency components. This suggests that, in the case of consonant chords, difference tones generated by interactions between notes in the cochlea enhance the perception of consonance. Furthermore, individuals with a greater distinction between consonant and dissonant chords in the FFR to individual harmonics had a stronger preference for consonant over dissonant chords. Overall, the results provide compelling evidence for the role of neural temporal coding in the perception of consonance, and suggest that the representation of harmonicity in phase locked neural firing drives the perception of consonance. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Speech perception at the interface of neurobiology and linguistics.

PubMed

Poeppel, David; Idsardi, William J; van Wassenhove, Virginie

2008-03-12

Speech perception consists of a set of computations that take continuously varying acoustic waveforms as input and generate discrete representations that make contact with the lexical representations stored in long-term memory as output. Because the perceptual objects that are recognized by the speech perception enter into subsequent linguistic computation, the format that is used for lexical representation and processing fundamentally constrains the speech perceptual processes. Consequently, theories of speech perception must, at some level, be tightly linked to theories of lexical representation. Minimally, speech perception must yield representations that smoothly and rapidly interface with stored lexical items. Adopting the perspective of Marr, we argue and provide neurobiological and psychophysical evidence for the following research programme. First, at the implementational level, speech perception is a multi-time resolution process, with perceptual analyses occurring concurrently on at least two time scales (approx. 20-80 ms, approx. 150-300 ms), commensurate with (sub)segmental and syllabic analyses, respectively. Second, at the algorithmic level, we suggest that perception proceeds on the basis of internal forward models, or uses an 'analysis-by-synthesis' approach. Third, at the computational level (in the sense of Marr), the theory of lexical representation that we adopt is principally informed by phonological research and assumes that words are represented in the mental lexicon in terms of sequences of discrete segments composed of distinctive features. One important goal of the research programme is to develop linking hypotheses between putative neurobiological primitives (e.g. temporal primitives) and those primitives derived from linguistic inquiry, to arrive ultimately at a biologically sensible and theoretically satisfying model of representation and computation in speech.

Models of Acetylcholine and Dopamine Signals Differentially Improve Neural Representations

PubMed Central

Holca-Lamarre, Raphaël; Lücke, Jörg; Obermayer, Klaus

2017-01-01

Biological and artificial neural networks (ANNs) represent input signals as patterns of neural activity. In biology, neuromodulators can trigger important reorganizations of these neural representations. For instance, pairing a stimulus with the release of either acetylcholine (ACh) or dopamine (DA) evokes long lasting increases in the responses of neurons to the paired stimulus. The functional roles of ACh and DA in rearranging representations remain largely unknown. Here, we address this question using a Hebbian-learning neural network model. Our aim is both to gain a functional understanding of ACh and DA transmission in shaping biological representations and to explore neuromodulator-inspired learning rules for ANNs. We model the effects of ACh and DA on synaptic plasticity and confirm that stimuli coinciding with greater neuromodulator activation are over represented in the network. We then simulate the physiological release schedules of ACh and DA. We measure the impact of neuromodulator release on the network's representation and on its performance on a classification task. We find that ACh and DA trigger distinct changes in neural representations that both improve performance. The putative ACh signal redistributes neural preferences so that more neurons encode stimulus classes that are challenging for the network. The putative DA signal adapts synaptic weights so that they better match the classes of the task at hand. Our model thus offers a functional explanation for the effects of ACh and DA on cortical representations. Additionally, our learning algorithm yields performances comparable to those of state-of-the-art optimisation methods in multi-layer perceptrons while requiring weaker supervision signals and interacting with synaptically-local weight updates. PMID:28690509

Feature integration in visual working memory: parietal gamma activity is related to cognitive coordination

PubMed Central

Muthukumaraswamy, Suresh D.; Hibbs, Carina S.; Shapiro, Kimron L.; Bracewell, R. Martyn; Singh, Krish D.; Linden, David E. J.

2011-01-01

The mechanism by which distinct subprocesses in the brain are coordinated is a central conundrum of systems neuroscience. The parietal lobe is thought to play a key role in visual feature integration, and oscillatory activity in the gamma frequency range has been associated with perception of coherent objects and other tasks requiring neural coordination. Here, we examined the neural correlates of integrating mental representations in working memory and hypothesized that parietal gamma activity would be related to the success of cognitive coordination. Working memory is a classic example of a cognitive operation that requires the coordinated processing of different types of information and the contribution of multiple cognitive domains. Using magnetoencephalography (MEG), we report parietal activity in the high gamma (80–100 Hz) range during manipulation of visual and spatial information (colors and angles) in working memory. This parietal gamma activity was significantly higher during manipulation of visual-spatial conjunctions compared with single features. Furthermore, gamma activity correlated with successful performance during the conjunction task but not during the component tasks. Cortical gamma activity in parietal cortex may therefore play a role in cognitive coordination. PMID:21940605

Pathogenic implications of iron accumulation in multiple sclerosis

PubMed Central

Williams, Rachel; Buchheit, Cassandra L.; Berman, Nancy E. J.; LeVine, Steven M.

2011-01-01

Iron, an essential element used for a multitude of biochemical reactions, abnormally accumulates in the central nervous system of patients with multiple sclerosis (MS). The mechanisms of abnormal iron deposition in MS are not fully understood, nor do we know whether these deposits have adverse consequences, i.e., contribute to pathogenesis. With some exceptions, excess levels of iron are represented concomitantly in multiple deep gray matter structures often with bilateral representation, while in white matter pathological iron deposits are usually located at sites of inflammation that are associated with veins. These distinct spatial patterns suggest disparate mechanisms of iron accumulation between these regions. Iron has been postulated to promote disease activity in MS by various means: 1) iron can amplify the activated state of microglia resulting in the increased production of proinflammatory mediators; 2) excess intracellular iron deposits could promote mitochondria dysfunction; and 3) improperly managed iron could catalyze the production of damaging reactive oxygen species. The pathological consequences of abnormal iron deposits may be dependent on the affected brain region and/or accumulation process. Here we review putative mechanisms of enhanced iron uptake in MS and address the likely roles of iron in the pathogenesis of this disease. PMID:22004421

Locating object knowledge in the brain: comment on Bowers's (2009) attempt to revive the grandmother cell hypothesis.

PubMed

Plaut, David C; McClelland, James L

2010-01-01

According to Bowers, the finding that there are neurons with highly selective responses to familiar stimuli supports theories positing localist representations over approaches positing the type of distributed representations typically found in parallel distributed processing (PDP) models. However, his conclusions derive from an overly narrow view of the range of possible distributed representations and of the role that PDP models can play in exploring their properties. Although it is true that current distributed theories face challenges in accounting for both neural and behavioral data, the proposed localist account--to the extent that it is articulated at all--runs into more fundamental difficulties. Central to these difficulties is the problem of specifying the set of entities a localist unit represents.

Using texts in science education: cognitive processes and knowledge representation.

PubMed

van den Broek, Paul

2010-04-23

Texts form a powerful tool in teaching concepts and principles in science. How do readers extract information from a text, and what are the limitations in this process? Central to comprehension of and learning from a text is the construction of a coherent mental representation that integrates the textual information and relevant background knowledge. This representation engenders learning if it expands the reader's existing knowledge base or if it corrects misconceptions in this knowledge base. The Landscape Model captures the reading process and the influences of reader characteristics (such as working-memory capacity, reading goal, prior knowledge, and inferential skills) and text characteristics (such as content/structure of presented information, processing demands, and textual cues). The model suggests factors that can optimize--or jeopardize--learning science from text.

A Computational Model of Reasoning from the Clinical Literature

PubMed Central

Rennels, Glenn D.

1986-01-01

This paper explores the premise that a formalized representation of empirical studies can play a central role in computer-based decision support. The specific motivations underlying this research include the following propositions: 1. Reasoning from experimental evidence contained in the clinical literature is central to the decisions physicians make in patient care. 2. A computational model, based upon a declarative representation for published reports of clinical studies, can drive a computer program that selectively tailors knowledge of the clinical literature as it is applied to a particular case. 3. The development of such a computational model is an important first step toward filling a void in computer-based decision support systems. Furthermore, the model may help us better understand the general principles of reasoning from experimental evidence both in medicine and other domains. Roundsman is a developmental computer system which draws upon structured representations of the clinical literature in order to critique plans for the management of primary breast cancer. Roundsman is able to produce patient-specific analyses of breast cancer management options based on the 24 clinical studies currently encoded in its knowledge base. The Roundsman system is a first step in exploring how the computer can help to bring a critical analysis of the relevant literature to the physician, structured around a particular patient and treatment decision.

Deployment of spatial attention towards locations in memory representations. An EEG study.

PubMed

Leszczyński, Marcin; Wykowska, Agnieszka; Perez-Osorio, Jairo; Müller, Hermann J

2013-01-01

Recalling information from visual short-term memory (VSTM) involves the same neural mechanisms as attending to an actually perceived scene. In particular, retrieval from VSTM has been associated with orienting of visual attention towards a location within a spatially-organized memory representation. However, an open question concerns whether spatial attention is also recruited during VSTM retrieval even when performing the task does not require access to spatial coordinates of items in the memorized scene. The present study combined a visual search task with a modified, delayed central probe protocol, together with EEG analysis, to answer this question. We found a temporal contralateral negativity (TCN) elicited by a centrally presented go-signal which was spatially uninformative and featurally unrelated to the search target and informed participants only about a response key that they had to press to indicate a prepared target-present vs. -absent decision. This lateralization during VSTM retrieval (TCN) provides strong evidence of a shift of attention towards the target location in the memory representation, which occurred despite the fact that the present task required no spatial (or featural) information from the search to be encoded, maintained, and retrieved to produce the correct response and that the go-signal did not itself specify any information relating to the location and defining feature of the target.

GRAPES-Grounding representations in action, perception, and emotion systems: How object properties and categories are represented in the human brain.

PubMed

Martin, Alex

2016-08-01

In this article, I discuss some of the latest functional neuroimaging findings on the organization of object concepts in the human brain. I argue that these data provide strong support for viewing concepts as the products of highly interactive neural circuits grounded in the action, perception, and emotion systems. The nodes of these circuits are defined by regions representing specific object properties (e.g., form, color, and motion) and thus are property-specific, rather than strictly modality-specific. How these circuits are modified by external and internal environmental demands, the distinction between representational content and format, and the grounding of abstract social concepts are also discussed.

[Municipal Health Councils: activity and representation of grassroots communities].

PubMed

Gerschman, Silvia

2004-01-01

This article was based on the results of research concerning health policy in municipalities that achieved the most extensive development of decentralization and innovation in the State of Rio de Janeiro, Brazil. The study applied a questionnaire for health system users' representatives in Municipal Health Councils. The central issues were: the Councils' political role; social control by the Councils, viewed as surveillance by organized society over government actions; the nature of social representation exercised by the Council members; and the type of mandate they serve. Community representatives in the Councils reinforce aspects pertaining to the exercise of representation in unequal societies. There is a predominance of a differentiated elite consisting of older males with more schooling and higher income than the community average. The notion of "social control" as the basis for the Councils is difficult for the members to grasp. Exercise of representation is diffuse, occurring by way of designation by community associations, election in assemblies, or designation by institutional health policy agencies.

A simplified formalism of the algebra of partially transposed permutation operators with applications

NASA Astrophysics Data System (ADS)

Mozrzymas, Marek; Studziński, Michał; Horodecki, Michał

2018-03-01

Herein we continue the study of the representation theory of the algebra of permutation operators acting on the n -fold tensor product space, partially transposed on the last subsystem. We develop the concept of partially reduced irreducible representations, which allows us to significantly simplify previously proved theorems and, most importantly, derive new results for irreducible representations of the mentioned algebra. In our analysis we are able to reduce the complexity of the central expressions by getting rid of sums over all permutations from the symmetric group, obtaining equations which are much more handy in practical applications. We also find relatively simple matrix representations for the generators of the underlying algebra. The obtained simplifications and developments are applied to derive the characteristics of a deterministic port-based teleportation scheme written purely in terms of irreducible representations of the studied algebra. We solve an eigenproblem for the generators of the algebra, which is the first step towards a hybrid port-based teleportation scheme and gives us new proofs of the asymptotic behaviour of teleportation fidelity. We also show a connection between the density operator characterising port-based teleportation and a particular matrix composed of an irreducible representation of the symmetric group, which encodes properties of the investigated algebra.

[Social representations of health and disease and the implications in nursing care: a structural analysis].

PubMed

de Oliveira, D C; de Sá, C P

2001-01-01

This study characterizes the social representations of the health-disease process of subjects resident in two districts of São Paulo, in order to identify the needs of health and the orientation of the nursing action. Free evocations recollections from 418 adults on the themes health and disease. Data analyse was developed thought a descriptive and structural analysis of the social representations, through the methodology of construction of the "picture of four houses", categorization and similitude analysis. The results show central senses of the representation, the possitiveness of the health, are anchored in a divine entity, and accompanied of notions that associate health to prevention of diseases, to biological needs, to activity and to which the attitude assumed to the disease. The representation structure of disease is similar, in inverse sense, to the one of the health: god is the center of the social representation, in its negative version, being expressed in the body through the pain, of the death and the inactivity and--in the spirit--through the sadness and of the depression. The discussion is that psychological character of health and of disease, that is expressed under the psychosocial needs committed, and the consequent need of rethinking the technological model of work in nursing.

48 CFR 19.308 - Protesting a firm's status as an economically disadvantaged women-owned small business (EDWOSB...

Code of Federal Regulations, 2011 CFR

2011-10-01

... Central Contractor Registration (CCR) and Online Representations and Certifications Application (ORCA) as... its designation in CCR and ORCA as an EDWOSB or WOSB concern, and shall not submit an offer as an...

Interpretations of Graphs by University Biology Students and Practicing Scientists: Toward a Social Practice View of Scientific Representation Practices.

ERIC Educational Resources Information Center

Bowen, G. Michael; Roth, Wolff-Michael; McGinn, Michelle K.

1999-01-01

Describes a study of the similarities and differences in graph-related interpretations between scientists and college students engaged in collective graph interpretation. Concludes that while many students learned to provide correct answers to scientific graphing questions, they did not come to make linguistic distinctions or increase their…

"Styled by Their Perceptions": Black Adolescent Girls Interpret Representations of Black Females in Popular Culture

ERIC Educational Resources Information Center

Muhammad, Gholnecsar E.; McArthur, Sherell A.

2015-01-01

Identity formation is a critical process shaping the lives of adolescents and can present distinct challenges for Black adolescent girls who are positioned in society to negotiate ideals of self when presented with false and incomplete images representing Black girlhood. Researchers have found distorted images of Black femininity derived from…

EEG Decoding of Semantic Category Reveals Distributed Representations for Single Concepts

ERIC Educational Resources Information Center

Murphy, Brian; Poesio, Massimo; Bovolo, Francesca; Bruzzone, Lorenzo; Dalponte, Michele; Lakany, Heba

2011-01-01

Achieving a clearer picture of categorial distinctions in the brain is essential for our understanding of the conceptual lexicon, but much more fine-grained investigations are required in order for this evidence to contribute to lexical research. Here we present a collection of advanced data-mining techniques that allows the category of individual…

Visual Representation of Eye Gaze Is Coded by a Nonopponent Multichannel System

ERIC Educational Resources Information Center

Calder, Andrew J.; Jenkins, Rob; Cassel, Anneli; Clifford, Colin W. G.

2008-01-01

To date, there is no functional account of the visual perception of gaze in humans. Previous work has demonstrated that left gaze and right gaze are represented by separate mechanisms. However, these data are consistent with either a multichannel system comprising separate channels for distinct gaze directions (e.g., left, direct, and right) or an…

Rise Time and Formant Transition Duration in the Discrimination of Speech Sounds: The Ba-Wa Distinction in Developmental Dyslexia

ERIC Educational Resources Information Center

Goswami, Usha; Fosker, Tim; Huss, Martina; Mead, Natasha; Szucs, Denes

2011-01-01

Across languages, children with developmental dyslexia have a specific difficulty with the neural representation of the sound structure (phonological structure) of speech. One likely cause of their difficulties with phonology is a perceptual difficulty in auditory temporal processing (Tallal, 1980). Tallal (1980) proposed that basic auditory…

Conceptual Distinctiveness Supports Detailed Visual Long-Term Memory for Real-World Objects

ERIC Educational Resources Information Center

Konkle, Talia; Brady, Timothy F.; Alvarez, George A.; Oliva, Aude

2010-01-01

Humans have a massive capacity to store detailed information in visual long-term memory. The present studies explored the fidelity of these visual long-term memory representations and examined how conceptual and perceptual features of object categories support this capacity. Observers viewed 2,800 object images with a different number of exemplars…

Evaluating reserves for species richness and representation in northern California

Treesearch

Jeffrey R. Dunk; William J. Zielinski; Hartwell Jr. Welsh

2006-01-01

The Klamath-Siskiyou forests of northern California and southern Oregon are recognized as an area of globally outstanding biological distinctiveness. When evaluated at a national or global level, this region is often, necessarily, considered to be uniformly diverse. Due to large variation in biotic and abiotic variables throughout this region, however, it is unlikely...

On the black hole lens and its foci

NASA Technical Reports Server (NTRS)

Eshleman, Von R.; Gurrola, Eric M.; Lindal, Gunnar F.

1989-01-01

Methods developed for radio occultation studies of planetary atmospheres are used to predict the electromagnetic focusing properties of a refracting lens representation of a Schwarzschild black hole. The infinity of foci are of three distinct types: a principal forward axial focus which is by far the strongest; higher-order forward axial foci; and backward conical foci with axial nulls.

The Medium Is the Message: Pictures and Objects Evoke Distinct Conceptual Relations in Parent-Child Conversations

ERIC Educational Resources Information Center

Ware, Elizabeth A.; Gelman, Susan A.; Kleinberg, Felicia

2013-01-01

An important developmental task is learning to organize experience by forming conceptual relations among entities. (For example, a "lion" and a "snake" can be linked because both are animals; a lion and a cage can be linked because the "lion" lives in the "cage".) We propose that representational medium…

Sketching in Design Journals: An Analysis of Visual Representations in the Product Design Process

ERIC Educational Resources Information Center

Lau, Kimberly; Oehlberg, Lora; Agogino, Alice

2009-01-01

This paper explores the sketching behavior of designers and the role of sketching in the design process. Observations from a descriptive study of sketches provided in design journals, characterized by a protocol measuring sketching activities, are presented. A distinction is made between journals that are entirely tangible and those that contain…

The Low and Narrow: A Preliminary Test of the Association between Depressive Symptoms and Deficits in Producing Divergent Inferences

ERIC Educational Resources Information Center

Liknaitzky, Paul; Smillie, Luke D.; Allen, Nicholas B.

2018-01-01

Depression is associated with biased interpretations and beliefs that are resistant to change. This kind of cognitive rigidity may depend on two distinct factors--a reduced ability for processing information that conflicts with these interpretations and beliefs and a reduced ability for generating alternative representations. Although depressive…

Depth of Lexical-Semantic Processing and Sentential Load

ERIC Educational Resources Information Center

Sanford, Alison J. S.; Sanford, Anthony J.; Filik, Ruth; Molle, Jo

2005-01-01

The text-change detection task has been used to show that changes are more readily detected for words that fall under narrow focus than broad focus (Sturt, Sanford, Stewart, & Dawydiak, 2004), and that narrow focus appears to lead to finer semantic distinctions being held in the representation of the word. The present experiments apply the same…

A COMPARISON OF TAXONOMIC DISTINCTNESS VERSUS RICHNESS AS CRITERIA FOR SETTING CONSERVATION PRIORITIES FOR NORTH AMERICAN BIRDS. (R825311)

EPA Science Inventory

Abstract

In choosing sites for a conservation reserve network, representation of the greatest number of species in the sites selected is a common objective. This approach implicitly assumes that all species have equal conservation value. An alternative objective is to ...

The importance of context: evidence that contextual representations increase intrusive memories.

PubMed

Pearson, David G; Ross, Fiona D C; Webster, Victoria L

2012-03-01

Intrusive memories appear to enter consciousness via involuntary rather than deliberate recollection. Some clinical accounts of PTSD seek to explain this phenomenon by making a clear distinction between the encoding of sensory-based and contextual representations. Contextual representations have been claimed to actively reduce intrusions by anchoring encoded perceptual data for an event in memory. The current analogue trauma study examined this hypothesis by manipulating contextual information independently from encoded sensory-perceptual information. Participants' viewed images selected from the International Affective Picture System that depicted scenes of violence and bodily injury. Images were viewed either under neutral conditions or paired with contextual information. Two experiments revealed a significant increase in memory intrusions for images paired with contextual information in comparison to the same images viewed under neutral conditions. In contrast to the observed increase in intrusion frequency there was no effect of contextual representations on voluntary memory for the images. The vividness and emotionality of memory intrusions were also unaffected. The analogue trauma paradigm may fail to replicate the effect of extreme stress on encoding postulated to occur during PTSD. These findings question the assertion that intrusive memories develop from a lack of integration between sensory-based and contextual representations in memory. Instead it is argued contextual representations play a causal role in increasing the frequency of intrusions by increasing the sensitivity of memory to involuntary retrieval by associated internal and external cues. Copyright © 2011 Elsevier Ltd. All rights reserved.

ERP signs of categorical and supra-categorical processing of visual information.

PubMed

Zani, Alberto; Marsili, Giulia; Senerchia, Annapaola; Orlandi, Andrea; Citron, Francesca M M; Rizzi, Ezia; Proverbio, Alice M

2015-01-01

The aim of the present study was to investigate to what extent shared and distinct brain mechanisms are possibly subserving the processing of visual supra-categorical and categorical knowledge as observed with event-related potentials of the brain. Access time to these knowledge types was also investigated. Picture pairs of animals, objects, and mixed types were presented. Participants were asked to decide whether each pair contained pictures belonging to the same category (either animals or man-made objects) or to different categories by pressing one of two buttons. Response accuracy and reaction times (RTs) were also recorded. Both ERPs and RTs were grand-averaged separately for the same-different supra-categories and the animal-object categories. Behavioral performance was faster for more endomorphic pairs, i.e., animals vs. objects and same vs. different category pairs. For ERPs, a modulation of the earliest C1 and subsequent P1 responses to the same vs. different supra-category pairs, but not to the animal vs. object category pairs, was found. This finding supports the view that early afferent processing in the striate cortex can be boosted as a by-product of attention allocated to the processing of shapes and basic features that are mismatched, but not to their semantic quintessence, during same-different supra-categorical judgment. Most importantly, the fact that this processing accrual occurred independent of a traditional experimental condition requiring selective attention to a stimulus source out of the various sources addressed makes it conceivable that this processing accrual may arise from the attentional demand deriving from the alternate focusing of visual attention within and across stimulus categorical pairs' basic structural features. Additional posterior ERP reflections of the brain more prominently processing animal category and same-category pairs were observed at the N1 and N2 levels, respectively, as well as at a late positive complex level, overall most likely related to different stages of analysis of the greater endomorphy of these shape groups. Conversely, an enhanced fronto-central and fronto-lateral N2 as well as a centro-parietal N400 to man-made objects and different-category pairs were found, possibly indexing processing of these entities' lower endomorphy and isomorphy at the basic features and semantic levels, respectively. Overall, the present ERP results revealed shared and distinct mechanisms of access to supra-categorical and categorical knowledge in the same way in which shared and distinct neural representations underlie the processing of diverse semantic categories. Additionally, they outlined the serial nature of categorical and supra-categorical representations, indicating the sequential steps of access to these separate knowledge types. Copyright © 2014 Elsevier B.V. All rights reserved.

Physics instruction induces changes in neural knowledge representation during successive stages of learning.

PubMed

Mason, Robert A; Just, Marcel Adam

2015-05-01

Incremental instruction on the workings of a set of mechanical systems induced a progression of changes in the neural representations of the systems. The neural representations of four mechanical systems were assessed before, during, and after three phases of incremental instruction (which first provided information about the system components, then provided partial causal information, and finally provided full functional information). In 14 participants, the neural representations of four systems (a bathroom scale, a fire extinguisher, an automobile braking system, and a trumpet) were assessed using three recently developed techniques: (1) machine learning and classification of multi-voxel patterns; (2) localization of consistently responding voxels; and (3) representational similarity analysis (RSA). The neural representations of the systems progressed through four stages, or states, involving spatially and temporally distinct multi-voxel patterns: (1) initially, the representation was primarily visual (occipital cortex); (2) it subsequently included a large parietal component; (3) it eventually became cortically diverse (frontal, parietal, temporal, and medial frontal regions); and (4) at the end, it demonstrated a strong frontal cortex weighting (frontal and motor regions). At each stage of knowledge, it was possible for a classifier to identify which one of four mechanical systems a participant was thinking about, based on their brain activation patterns. The progression of representational states was suggestive of progressive stages of learning: (1) encoding information from the display; (2) mental animation, possibly involving imagining the components moving; (3) generating causal hypotheses associated with mental animation; and finally (4) determining how a person (probably oneself) would interact with the system. This interpretation yields an initial, cortically-grounded, theory of learning of physical systems that potentially can be related to cognitive learning theories by suggesting links between cortical representations, stages of learning, and the understanding of simple systems. Copyright © 2015 Elsevier Inc. All rights reserved.

The effect of contextual cues on the encoding of motor memories.

PubMed

Howard, Ian S; Wolpert, Daniel M; Franklin, David W

2013-05-01

Several studies have shown that sensory contextual cues can reduce the interference observed during learning of opposing force fields. However, because each study examined a small set of cues, often in a unique paradigm, the relative efficacy of different sensory contextual cues is unclear. In the present study we quantify how seven contextual cues, some investigated previously and some novel, affect the formation and recall of motor memories. Subjects made movements in a velocity-dependent curl field, with direction varying randomly from trial to trial but always associated with a unique contextual cue. Linking field direction to the cursor or background color, or to peripheral visual motion cues, did not reduce interference. In contrast, the orientation of a visual object attached to the hand cursor significantly reduced interference, albeit by a small amount. When the fields were associated with movement in different locations in the workspace, a substantial reduction in interference was observed. We tested whether this reduction in interference was due to the different locations of the visual feedback (targets and cursor) or the movements (proprioceptive). When the fields were associated only with changes in visual display location (movements always made centrally) or only with changes in the movement location (visual feedback always displayed centrally), a substantial reduction in interference was observed. These results show that although some visual cues can lead to the formation and recall of distinct representations in motor memory, changes in spatial visual and proprioceptive states of the movement are far more effective than changes in simple visual contextual cues.

Update on Aire and thymic negative selection.

PubMed

Passos, Geraldo A; Speck-Hernandez, Cesar A; Assis, Amanda F; Mendes-da-Cruz, Daniella A

2018-01-01

Twenty years ago, the autoimmune regulator (Aire) gene was associated with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, and was cloned and sequenced. Its importance goes beyond its abstract link with human autoimmune disease. Aire identification opened new perspectives to better understand the molecular basis of central tolerance and self-non-self distinction, the main properties of the immune system. Since 1997, a growing number of immunologists and molecular geneticists have made important discoveries about the function of Aire, which is essentially a pleiotropic gene. Aire is one of the functional markers in medullary thymic epithelial cells (mTECs), controlling their differentiation and expression of peripheral tissue antigens (PTAs), mTEC-thymocyte adhesion and the expression of microRNAs, among other functions. With Aire, the immunological tolerance became even more apparent from the molecular genetics point of view. Currently, mTECs represent the most unusual cells because they express almost the entire functional genome but still maintain their identity. Due to the enormous diversity of PTAs, this uncommon gene expression pattern was termed promiscuous gene expression, the interpretation of which is essentially immunological - i.e. it is related to self-representation in the thymus. Therefore, this knowledge is strongly linked to the negative selection of autoreactive thymocytes. In this update, we focus on the most relevant results of Aire as a transcriptional and post-transcriptional controller of PTAs in mTECs, its mechanism of action, and its influence on the negative selection of autoreactive thymocytes as the bases of the induction of central tolerance and prevention of autoimmune diseases. © 2017 John Wiley & Sons Ltd.

Shared knowledge or shared affordances? Insights from an ecological dynamics approach to team coordination in sports.

PubMed

Silva, Pedro; Garganta, Júlio; Araújo, Duarte; Davids, Keith; Aguiar, Paulo

2013-09-01

Previous research has proposed that team coordination is based on shared knowledge of the performance context, responsible for linking teammates' mental representations for collective, internalized action solutions. However, this representational approach raises many questions including: how do individual schemata of team members become reformulated together? How much time does it take for this collective cognitive process to occur? How do different cues perceived by different individuals sustain a general shared mental representation? This representational approach is challenged by an ecological dynamics perspective of shared knowledge in team coordination. We argue that the traditional shared knowledge assumption is predicated on 'knowledge about' the environment, which can be used to share knowledge and influence intentions of others prior to competition. Rather, during competitive performance, the control of action by perceiving surrounding informational constraints is expressed in 'knowledge of' the environment. This crucial distinction emphasizes perception of shared affordances (for others and of others) as the main communication channel between team members during team coordination tasks. From this perspective, the emergence of coordinated behaviours in sports teams is based on the formation of interpersonal synergies between players resulting from collective actions predicated on shared affordances.

Mental Representations of Weekdays

PubMed Central

Ellis, David A.; Wiseman, Richard; Jenkins, Rob

2015-01-01

Keeping social appointments involves keeping track of what day it is. In practice, mismatches between apparent day and actual day are common. For example, a person might think the current day is Wednesday when in fact it is Thursday. Here we show that such mismatches are highly systematic, and can be traced to specific properties of their mental representations. In Study 1, mismatches between apparent day and actual day occurred more frequently on midweek days (Tuesday, Wednesday, and Thursday) than on other days, and were mainly due to intrusions from immediately neighboring days. In Study 2, reaction times to report the current day were fastest on Monday and Friday, and slowest midweek. In Study 3, participants generated fewer semantic associations for “Tuesday”, “Wednesday” and “Thursday” than for other weekday names. Similarly, Google searches found fewer occurrences of midweek days in webpages and books. Analysis of affective norms revealed that participants’ associations were strongly negative for Monday, strongly positive for Friday, and graded over the intervening days. Midweek days are confusable because their mental representations are sparse and similar. Mondays and Fridays are less confusable because their mental representations are rich and distinctive, forming two extremes along a continuum of change. PMID:26288194

Of Papers and Pens: Polysemes and Homophones in Lexical (mis)Selection.

PubMed

Li, Leon; Slevc, L Robert

2017-05-01

Every word signifies multiple senses. Many studies using comprehension-based measures suggest that polysemes' senses (e.g., paper as in printer paper or term paper) share lexical representations, whereas homophones' meanings (e.g., pen as in ballpoint pen or pig pen) correspond to distinct lexical representations. Less is known about the lexical representations of polysemes compared to homophones in language production. In this study, speakers named pictures after reading sentence fragments that primed polysemes and homophones either as direct competitors to pictures (i.e., semantic-competitors), or as indirect-competitors to pictures (e.g., polysemous senses of semantic competitors, or homophonous meanings of semantic competitors). Polysemes (e.g., paper) elicited equal numbers of intrusions to picture names (e.g., cardboard) compared to in control conditions whether primed as direct competitors (printer paper) or as indirect-competitors (term paper). This contrasted with the finding that homophones (e.g., pen) elicited more intrusions to picture names (e.g., crayon) compared to in control conditions when primed as direct competitors (ballpoint pen) than when primed as indirect-competitors (pig pen). These results suggest that polysemes, unlike homophones, are stored and retrieved as unified lexical representations. Copyright © 2016 Cognitive Science Society, Inc.

Dissociations in mathematical knowledge: case studies in Down's syndrome and Williams syndrome.

PubMed

Robinson, Sally J; Temple, Christine M

2013-02-01

A study is reported of mathematical vocabulary and factual mathematical knowledge in PQ, a 22 year old with Down's syndrome (DS) who has a verbal mental age (MA) of 9 years 2 months and ST, a 15 year old with Williams syndrome (WS) who has a verbal MA of 9 years 6 months, matched to typically developing controls. The number of mathematical words contained within PQ's lexical stores was significantly reduced as reflected by performance on lexical decision. PQ was also impaired at both naming from descriptions and describing mathematical words. These results contrast with normal lexical decision and item descriptions for concrete words reported recently for PQ (Robinson and Temple, 2010). PQ's recall of mathematical facts was also impaired, whilst his recall of general knowledge facts was normal. This performance in DS indicates a deficit in both lexical representation and semantic knowledge for mathematical words and mathematical facts. In contrast, ST, the teenager with WS had good accuracy on lexical decision, naming and generating definitions for mathematical words. This contrasted with the atypical performance with concrete words recently reported for ST (Robinson and Temple, 2009). Knowledge of addition facts and general knowledge facts was also unimpaired for ST, though knowledge of multiplication facts was weak. Together the cases form a double dissociation and provide support for the distinct representation of mathematical and concrete items within the lexical-semantic system during development. The dissociations between mathematical and general factual knowledge also indicate that different types of factual knowledge may be selectively impaired during development. There is further support for a modular structure within which mathematical vocabulary and mathematical knowledge have distinct representations. This supports the case for the independent representation of factual and language-based knowledge within the semantic system during development. Copyright © 2011 Elsevier Ltd. All rights reserved.

Quantum mechanics in non-inertial reference frames: Time-dependent rotations and loop prolongations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klink, W.H., E-mail: william-klink@uiowa.edu; Wickramasekara, S., E-mail: wickrama@grinnell.edu; Department of Physics, Grinnell College, Grinnell, IA 50112

2013-09-15

This is the fourth in a series of papers on developing a formulation of quantum mechanics in non-inertial reference frames. This formulation is grounded in a class of unitary cocycle representations of what we have called the Galilean line group, the generalization of the Galilei group to include transformations amongst non-inertial reference frames. These representations show that in quantum mechanics, just as the case in classical mechanics, the transformations to accelerating reference frames give rise to fictitious forces. In previous work, we have shown that there exist representations of the Galilean line group that uphold the non-relativistic equivalence principle asmore » well as representations that violate the equivalence principle. In these previous studies, the focus was on linear accelerations. In this paper, we undertake an extension of the formulation to include rotational accelerations. We show that the incorporation of rotational accelerations requires a class of loop prolongations of the Galilean line group and their unitary cocycle representations. We recover the centrifugal and Coriolis force effects from these loop representations. Loops are more general than groups in that their multiplication law need not be associative. Hence, our broad theoretical claim is that a Galilean quantum theory that holds in arbitrary non-inertial reference frames requires going beyond groups and group representations, the well-established framework for implementing symmetry transformations in quantum mechanics. -- Highlights: •A formulation of Galilean quantum mechanics in non-inertial reference frames is presented. •The Galilei group is generalized to infinite dimensional Galilean line group. •Loop prolongations of Galilean line group contain central extensions of Galilei group. •Unitary representations of the loops are constructed. •These representations lead to terms in the Hamiltonian corresponding to fictitious forces, including centrifugal and Coriolis forces.« less

Distinct medial temporal networks encode surprise during motivation by reward versus punishment

PubMed Central

Murty, Vishnu P.; LaBar, Kevin S.; Adcock, R. Alison

2016-01-01

Adaptive motivated behavior requires predictive internal representations of the environment, and surprising events are indications for encoding new representations of the environment. The medial temporal lobe memory system, including the hippocampus and surrounding cortex, encodes surprising events and is influenced by motivational state. Because behavior reflects the goals of an individual, we investigated whether motivational valence (i.e., pursuing rewards versus avoiding punishments) also impacts neural and mnemonic encoding of surprising events. During functional magnetic resonance imaging (fMRI), participants encountered perceptually unexpected events either during the pursuit of rewards or avoidance of punishments. Despite similar levels of motivation across groups, reward and punishment facilitated the processing of surprising events in different medial temporal lobe regions. Whereas during reward motivation, perceptual surprises enhanced activation in the hippocampus, during punishment motivation surprises instead enhanced activation in parahippocampal cortex. Further, we found that reward motivation facilitated hippocampal coupling with ventromedial PFC, whereas punishment motivation facilitated parahippocampal cortical coupling with orbitofrontal cortex. Behaviorally, post-scan testing revealed that reward, but not punishment, motivation resulted in greater memory selectivity for surprising events encountered during goal pursuit. Together these findings demonstrate that neuromodulatory systems engaged by anticipation of reward and punishment target separate components of the medial temporal lobe, modulating medial temporal lobe sensitivity and connectivity. Thus, reward and punishment motivation yield distinct neural contexts for learning, with distinct consequences for how surprises are incorporated into predictive mnemonic models of the environment. PMID:26854903

Distinct medial temporal networks encode surprise during motivation by reward versus punishment.

PubMed

Murty, Vishnu P; LaBar, Kevin S; Adcock, R Alison

2016-10-01

Adaptive motivated behavior requires predictive internal representations of the environment, and surprising events are indications for encoding new representations of the environment. The medial temporal lobe memory system, including the hippocampus and surrounding cortex, encodes surprising events and is influenced by motivational state. Because behavior reflects the goals of an individual, we investigated whether motivational valence (i.e., pursuing rewards versus avoiding punishments) also impacts neural and mnemonic encoding of surprising events. During functional magnetic resonance imaging (fMRI), participants encountered perceptually unexpected events either during the pursuit of rewards or avoidance of punishments. Despite similar levels of motivation across groups, reward and punishment facilitated the processing of surprising events in different medial temporal lobe regions. Whereas during reward motivation, perceptual surprises enhanced activation in the hippocampus, during punishment motivation surprises instead enhanced activation in parahippocampal cortex. Further, we found that reward motivation facilitated hippocampal coupling with ventromedial PFC, whereas punishment motivation facilitated parahippocampal cortical coupling with orbitofrontal cortex. Behaviorally, post-scan testing revealed that reward, but not punishment, motivation resulted in greater memory selectivity for surprising events encountered during goal pursuit. Together these findings demonstrate that neuromodulatory systems engaged by anticipation of reward and punishment target separate components of the medial temporal lobe, modulating medial temporal lobe sensitivity and connectivity. Thus, reward and punishment motivation yield distinct neural contexts for learning, with distinct consequences for how surprises are incorporated into predictive mnemonic models of the environment. Copyright © 2016 Elsevier Inc. All rights reserved.

The near real time Forensic Disaster Analysis of the central European flood in June 2013 - A graphical representation of the main results

NASA Astrophysics Data System (ADS)

Schröter, Kai; Elmer, Florian; Trieselmann, Werner; Kreibich, Heidi; Kunz, Michael; Khazai, Bijan; Dransch, Doris; Wenzel, Friedemann; Zschau, Jochen; Merz, Bruno; Mühr, Bernhard; Kunz-Plapp, Tina; Möhrle, Stella; Bessel, Tina; Fohringer, Joachim

2014-05-01

The Central European flood of June 2013 is one of the most severe flood events that have occurred in Central Europe in the past decades. All major German river basins were affected (Rhine, Danube, and Elbe as well as the smaller Weser catchment).In terms of spatial extent and event magnitude, it was the most severe event at least since 1950. Within the current research focus on near real time forensic disaster analysis, the Center for Disaster Management and Risk Reduction Technology (CEDIM) assessed and analysed the multiple facets of the flood event from the beginning. The aim is to describe the on-going event, analyse the event sources, link the physical characteristics to the impact and consequences of the event and to understand the root causes that turn the physical event into a disaster (or prevent it from becoming disastrous). For the near real time component of this research, tools for rapid assessment and concise presentation of analysis results are essential. This contribution provides a graphical summary of the results of the CEDIM-FDA analyses on the June 2013 flood. It demonstrates the potential of visual representations for improving the communication and hence usability of findings in a rapid, intelligible and expressive way as a valuable supplement to usual event reporting. It is based on analyses of the hydrometeorological sources, the flood pathways (from satellite imagery, data extraction from social media), the resilience of the affected regions, and causal loss analysis. The prototypical representation of the FDA-results for the June 2013 flood provides an important step in the development of graphical event templates for the visualisation of forensic disaster analyses. These are intended to become a standard component of future CEDIM-FDA event activities.

Unitary cocycle representations of the Galilean line group: Quantum mechanical principle of equivalence

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacGregor, B.R.; McCoy, A.E.; Wickramasekara, S., E-mail: wickrama@grinnell.edu

2012-09-15

We present a formalism of Galilean quantum mechanics in non-inertial reference frames and discuss its implications for the equivalence principle. This extension of quantum mechanics rests on the Galilean line group, the semidirect product of the real line and the group of analytic functions from the real line to the Euclidean group in three dimensions. This group provides transformations between all inertial and non-inertial reference frames and contains the Galilei group as a subgroup. We construct a certain class of unitary representations of the Galilean line group and show that these representations determine the structure of quantum mechanics in non-inertialmore » reference frames. Our representations of the Galilean line group contain the usual unitary projective representations of the Galilei group, but have a more intricate cocycle structure. The transformation formula for the Hamiltonian under the Galilean line group shows that in a non-inertial reference frame it acquires a fictitious potential energy term that is proportional to the inertial mass, suggesting the equivalence of inertial mass and gravitational mass in quantum mechanics. - Highlights: Black-Right-Pointing-Pointer A formulation of Galilean quantum mechanics in non-inertial reference frames is given. Black-Right-Pointing-Pointer The key concept is the Galilean line group, an infinite dimensional group. Black-Right-Pointing-Pointer Unitary, cocycle representations of the Galilean line group are constructed. Black-Right-Pointing-Pointer A non-central extension of the group underlies these representations. Black-Right-Pointing-Pointer Quantum equivalence principle and gravity emerge from these representations.« less

Use of dynamical downscaling to improve the simulation of Central U.S. warm season precipitation in CMIP5 models

NASA Astrophysics Data System (ADS)

Harding, Keith J.; Snyder, Peter K.; Liess, Stefan

2013-11-01

supporting exceptionally productive agricultural lands, the Central U.S. is susceptible to severe droughts and floods. Such precipitation extremes are expected to worsen with climate change. However, future projections are highly uncertain as global climate models (GCMs) generally fail to resolve precipitation extremes. In this study, we assess how well models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) simulate summer means, variability, extremes, and the diurnal cycle of Central U.S. summer rainfall. Output from a subset of historical CMIP5 simulations are used to drive the Weather Research and Forecasting model to determine whether dynamical downscaling improves the representation of Central U.S. rainfall. We investigate which boundary conditions influence dynamically downscaled precipitation estimates and identify GCMs that can reasonably simulate precipitation when downscaled. The CMIP5 models simulate the seasonal mean and variability of summer rainfall reasonably well but fail to resolve extremes, the diurnal cycle, and the dynamic forcing of precipitation. Downscaling to 30 km improves these characteristics of precipitation, with the greatest improvement in the representation of extremes. Additionally, sizeable diurnal cycle improvements occur with higher (10 km) resolution and convective parameterization disabled, as the daily rainfall peak shifts 4 h closer to observations than 30 km resolution simulations. This lends greater confidence that the mechanisms responsible for producing rainfall are better simulated. Because dynamical downscaling can more accurately simulate these aspects of Central U.S. summer rainfall, policymakers can have added confidence in dynamically downscaled rainfall projections, allowing for more targeted adaptation and mitigation.

Teachers' social representations on drug use in a secondary school.

PubMed

Martini, Jussara Gue; Furegato, Antonia Regina Ferreira

2008-01-01

Increased concern regarding drug abuse among adolescents contributes to the elaboration of prevention programs at schools. This investigation aims to know teachers' social representations, regarding drug abuse, in a secondary school in Florianopolis, SC, Brazil. A total of 16 teachers of the 5th to 8th grades participated in the study. Data were collected through associations elaborated by teachers in response to the expression: drugs use/abuse. The teacher's representations are organized around a central concept - the vulnerable other: a needy adolescent, who becomes drugs user, highlighting the family, everyday coping, and the school's (in)visibility in prevention actions, as factors related. The complexity of factors involving drugs production, distribution and its commercialization, demands the implementation of actions that go beyond the scopes of education and health. The elaboration of inter-sector prevention programs considering local characteristics is necessary.

Wigner functions for noncommutative quantum mechanics: A group representation based construction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, S. Hasibul Hassan, E-mail: shhchowdhury@gmail.com; Department of Mathematics and Statistics, Concordia University, Montréal, Québec H3G 1M8; Ali, S. Twareque, E-mail: twareque.ali@concordia.ca

This paper is devoted to the construction and analysis of the Wigner functions for noncommutative quantum mechanics, their marginal distributions, and star-products, following a technique developed earlier, viz, using the unitary irreducible representations of the group G{sub NC}, which is the three fold central extension of the Abelian group of ℝ{sup 4}. These representations have been exhaustively studied in earlier papers. The group G{sub NC} is identified with the kinematical symmetry group of noncommutative quantum mechanics of a system with two degrees of freedom. The Wigner functions studied here reflect different levels of non-commutativity—both the operators of position and thosemore » of momentum not commuting, the position operators not commuting and finally, the case of standard quantum mechanics, obeying the canonical commutation relations only.« less

Episodic-like memory in the rat.

PubMed

Babb, Stephanie J; Crystal, Jonathon D

2006-07-11

A fundamental question in comparative cognition is whether animals remember unique, personal past experiences. It has long been argued that memories for specific events (referred to as episodic memory) are unique to humans. Recently, considerable evidence has accumulated to show that food-storing birds possess critical behavioral elements of episodic memory, referred to as episodic-like memory in acknowledgment of the fact that behavioral criteria do not assess subjective experiences. Here we show that rats have a detailed representation of remembered events and meet behavioral criteria for episodic-like memory. We provided rats with access to locations baited with distinctive (e.g., grape and raspberry) or nondistinctive (regular chow) flavors. Locations with a distinctive flavor replenished after a long but not a short delay, and locations with the nondistinctive flavor never replenished. One distinctive flavor was devalued after encoding its location by prefeeding that flavor (satiation) or by pairing it with lithium chloride (acquired taste aversion), while the other distinctive flavor was not devalued. The rats selectively decreased revisits to the devalued distinctive flavor but not to the nondevalued distinctive flavor. The present studies demonstrate that rats selectively encode the content of episodic-like memories.

Neural components of topographical representation

PubMed Central

Aguirre, Geoffrey K.; Zarahn, Eric; D’Esposito, Mark

1998-01-01

Studies of patients with focal brain damage suggest that topographical representation is subserved by dissociable neural subcomponents. This article offers a condensed review of the literature of “topographical disorientation” and describes several functional MRI studies designed to test hypotheses generated by that review. Three hypotheses are considered: (i) The parahippocampal cortex is critically involved in the acquisition of exocentric spatial information in humans; (ii) separable, posterior, dorsal, and ventral cortical regions subserve the perception and long term representation of position and identity, respectively, of landmarks; and (iii) there is a distinct area of the ventral occipitotemporal cortex that responds maximally to building stimuli and may play a role in the perception of salient landmarks. We conclude with a discussion of the inferential limitations of neuroimaging and lesion studies. It is proposed that combining these two approaches allows for inferences regarding the computational involvement of a neuroanatomical substrate in a given cognitive process although neither method can strictly support this conclusion alone. PMID:9448249

Children with autism's perception and understanding of ambiguous figures: evidence for pictorial metarepresentation, a research note.

PubMed

Wimmer, Marina C; Doherty, Martin J

2010-09-01

A large body of autism research over the last 20 years has shown that people with autism have difficulties understanding mental states. This has been conceived of as a metarepresentational deficit. An open question is whether people with autism's metarepresentational deficit is limited to the mental domain. This research explores individuals with autism's understanding of the representational nature of pictures. With the use of ambiguous figures, where a single stimulus is capable of representing two distinct referents, we compared metarepresentational abilities in the pictorial and mental domains and the perception of pictorial ambiguity. Our findings indicate that individuals with autism are impaired in mental metarepresentation but not in pictorial metarepresentation. These findings suggest that children with autism understand the representational nature of pictures. We conclude that children with autism's understanding of the representational nature of pictures is in advance of their metarepresentational understanding of mind. Their perception of figure ambiguity is comparable to the typical population.

Ambient clumsiness in virtual environments

NASA Astrophysics Data System (ADS)

Ruzanka, Silvia; Behar, Katherine

2010-01-01

A fundamental pursuit of Virtual Reality is the experience of a seamless connection between the user's body and actions within the simulation. Virtual worlds often mediate the relationship between the physical and virtual body through creating an idealized representation of the self in an idealized space. This paper argues that the very ubiquity of the medium of virtual environments, such as the massively popular Second Life, has now made them mundane, and that idealized representations are no longer appropriate. In our artwork we introduce the attribute of clumsiness to Second Life by creating and distributing scripts that cause users' avatars to exhibit unpredictable stumbling, tripping, and momentary poor coordination, thus subtly and unexpectedly intervening with, rather than amplifying, a user's intent. These behaviors are publicly distributed, and manifest only occasionally - rather than intentional, conscious actions, they are involuntary and ambient. We suggest that the physical human body is itself an imperfect interface, and that the continued blurring of distinctions between the physical body and virtual representations calls for the introduction of these mundane, clumsy elements.

Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization

PubMed Central

Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan EB; Kastner, Sabine; Hasson, Uri

2015-01-01

The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas. DOI: http://dx.doi.org/10.7554/eLife.03952.001 PMID:25695154

Artworks as dichotomous objects: implications for the scientific study of aesthetic experience

PubMed Central

Pepperell, Robert

2015-01-01

This paper addresses an issue that has been studied from both scientific and art theoretical perspectives, namely the dichotomous nature of representational artworks. Representational artworks are dichotomous in that they present us with two distinct aspects at once. In one aspect we are aware of what is represented while in the other we are aware of the material from which the representation is composed. The dichotomy arises due the incompatibility, indeed contradiction, between these aspects of awareness, both of which must be present if we are to fully appreciate the artwork. Examples from art history are given to show how artists have exploited this dichotomy in a way that conditions our response to their work. I hypothesize that the degree of manifest dichotomy in a work determines the strength of its aesthetic effect, and propose this could be experimentally tested. I conclude that scientific studies of aesthetic experience should take the dichotomous nature of artworks into account. PMID:26106312

The first pictures: perceptual foundations of Paleolithic art.

PubMed

Halverson, J

1992-01-01

Paleolithic representational art has a number of consistent characteristics: the subjects are almost always animals, depicted without scenic background, usually in profile, and mostly in outline; the means of representation are extremely economical, often consisting of only a few strokes that indicate the salient features of the animal which are sufficient to suggest the whole form; and it is naturalistic to a degree, but lacks anything like photographic realism. Two elementary questions are raised in this essay: (i) why did the earliest known attempts at depiction have just these characteristics and not others? and (ii) how are objects so minimally represented recognizable? The answers seem to lie with certain fundamental features of visual perception, especially figure-ground distinction, Gestalt principles of closure and good continuation, line surrogacy, component feature analysis, and canonical imaging. In the earliest pictures the graphic means used are such that they evoke the same visual responses as those involved in the perception of real-world forms, but eschew redundancies of color, texture, linear perspective, and completeness of representation.

Intercomparison and Uncertainty Assessment of Nine Evapotranspiration Estimates Over South America

NASA Astrophysics Data System (ADS)

Sörensson, Anna A.; Ruscica, Romina C.

2018-04-01

This study examines the uncertainties and the representations of anomalies of a set of evapotranspiration products over climatologically distinct regions of South America. The products, coming from land surface models, reanalysis, and remote sensing, are chosen from sources that are readily available to the community of users. The results show that the spatial patterns of maximum uncertainty differ among metrics, with dry regions showing maximum relative uncertainties of annual mean evapotranspiration, while energy-limited regions present maximum uncertainties in the representation of the annual cycle and monsoon regions in the representation of anomalous conditions. Furthermore, it is found that land surface models driven by observed atmospheric fields detect meteorological and agricultural droughts in dry regions unequivocally. The remote sensing products employed do not distinguish all agricultural droughts and this could be attributed to the forcing net radiation. The study also highlights important characteristics of individual data sets and recommends users to include assessments of sensitivity to evapotranspiration data sets in their studies, depending on region and nature of study to be conducted.

Adaptive multiscale processing for contrast enhancement

NASA Astrophysics Data System (ADS)

Laine, Andrew F.; Song, Shuwu; Fan, Jian; Huda, Walter; Honeyman, Janice C.; Steinbach, Barbara G.

1993-07-01

This paper introduces a novel approach for accomplishing mammographic feature analysis through overcomplete multiresolution representations. We show that efficient representations may be identified from digital mammograms within a continuum of scale space and used to enhance features of importance to mammography. Choosing analyzing functions that are well localized in both space and frequency, results in a powerful methodology for image analysis. We describe methods of contrast enhancement based on two overcomplete (redundant) multiscale representations: (1) Dyadic wavelet transform (2) (phi) -transform. Mammograms are reconstructed from transform coefficients modified at one or more levels by non-linear, logarithmic and constant scale-space weight functions. Multiscale edges identified within distinct levels of transform space provide a local support for enhancement throughout each decomposition. We demonstrate that features extracted from wavelet spaces can provide an adaptive mechanism for accomplishing local contrast enhancement. We suggest that multiscale detection and local enhancement of singularities may be effectively employed for the visualization of breast pathology without excessive noise amplification.

Global Representations of Goal-Directed Behavior in Distinct Cell Types of Mouse Neocortex

PubMed Central

Allen, William E.; Kauvar, Isaac V.; Chen, Michael Z.; Richman, Ethan B.; Yang, Samuel J.; Chan, Ken; Gradinaru, Viviana; Deverman, Benjamin E.; Luo, Liqun; Deisseroth, Karl

2017-01-01

SUMMARY The successful planning and execution of adaptive behaviors in mammals may require long-range coordination of neural networks throughout cerebral cortex. The neuronal implementation of signals that could orchestrate cortex-wide activity remains unclear. Here, we develop and apply methods for cortex-wide Ca2+ imaging in mice performing decision-making behavior and identify a global cortical representation of task engagement encoded in the activity dynamics of both single cells and superficial neuropil distributed across the majority of dorsal cortex. The activity of multiple molecularly defined cell types was found to reflect this representation with type-specific dynamics. Focal optogenetic inhibition tiled across cortex revealed a crucial role for frontal cortex in triggering this cortex-wide phenomenon; local inhibition of this region blocked both the cortex-wide response to task-initiating cues and the voluntary behavior. These findings reveal cell-type-specific processes in cortex for globally representing goal-directed behavior and identify a major cortical node that gates the global broadcast of task-related information. PMID:28521139

Body representations in the human brain revealed by kinesthetic illusions and their essential contributions to motor control and corporeal awareness.

PubMed

Naito, Eiichi; Morita, Tomoyo; Amemiya, Kaoru

2016-03-01

The human brain can generate a continuously changing postural model of our body. Somatic (proprioceptive) signals from skeletal muscles and joints contribute to the formation of the body representation. Recent neuroimaging studies of proprioceptive bodily illusions have elucidated the importance of three brain systems (motor network, specialized parietal systems, right inferior fronto-parietal network) in the formation of the human body representation. The motor network, especially the primary motor cortex, processes afferent input from skeletal muscles. Such information may contribute to the formation of kinematic/dynamic postural models of limbs, thereby enabling fast online feedback control. Distinct parietal regions appear to play specialized roles in the transformation/integration of information across different coordinate systems, which may subserve the adaptability and flexibility of the body representation. Finally, the right inferior fronto-parietal network, connected by the inferior branch of the superior longitudinal fasciculus, is consistently recruited when an individual experiences various types of bodily illusions and its possible roles relate to corporeal awareness, which is likely elicited through a series of neuronal processes of monitoring and accumulating bodily information and updating the body representation. Because this network is also recruited when identifying one's own features, the network activity could be a neuronal basis for self-consciousness. Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Automatic frame-centered object representation and integration revealed by iconic memory, visual priming, and backward masking.

PubMed

Lin, Zhicheng; He, Sheng

2012-10-25

Object identities ("what") and their spatial locations ("where") are processed in distinct pathways in the visual system, raising the question of how the what and where information is integrated. Because of object motions and eye movements, the retina-based representations are unstable, necessitating nonretinotopic representation and integration. A potential mechanism is to code and update objects according to their reference frames (i.e., frame-centered representation and integration). To isolate frame-centered processes, in a frame-to-frame apparent motion configuration, we (a) presented two preceding or trailing objects on the same frame, equidistant from the target on the other frame, to control for object-based (frame-based) effect and space-based effect, and (b) manipulated the target's relative location within its frame to probe frame-centered effect. We show that iconic memory, visual priming, and backward masking depend on objects' relative frame locations, orthogonal of the retinotopic coordinate. These findings not only reveal that iconic memory, visual priming, and backward masking can be nonretinotopic but also demonstrate that these processes are automatically constrained by contextual frames through a frame-centered mechanism. Thus, object representation is robustly and automatically coupled to its reference frame and continuously being updated through a frame-centered, location-specific mechanism. These findings lead to an object cabinet framework, in which objects ("files") within the reference frame ("cabinet") are orderly coded relative to the frame.

Local GABA receptor blockade reveals hindlimb responses in the SI forelimb-stump representation of neonatally amputated rats.

PubMed

Pluto, Charles P; Lane, Richard D; Rhoades, Robert W

2004-07-01

In adult rats that sustained forelimb amputation on the day of birth, there are numerous multi-unit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) that also respond to cutaneous stimulation of the hindlimb when cortical receptors for GABA are blocked. These normally suppressed hindlimb inputs originate in the SI hindlimb representation and synapse in the dysgranular cortex before exciting SI forelimb-stump neurons. In our previous studies, GABA (A + B) receptor blockade was achieved by topically applying a bicuculline methiodide/saclofen solution (BMI/SAC) to the cortical surface. This treatment blocks receptors throughout SI and does not allow determination of where along the above circuit the GABA-mediated suppression of hindlimb information occurs. In this study, focal injections of BMI/SAC were delivered to three distinct cortical regions that are involved in the hindlimb-to-forelimb-stump pathway. Blocking GABA receptors in the SI hindlimb representation and in the dysgranular cortex was largely ineffective in revealing hindlimb inputs ( approximately 10% of hindlimb inputs were revealed in both cases). In contrast, when the blockade was targeted at forelimb-stump recording sites, >80% of hindlimb inputs were revealed. Thus GABAergic interneurons within the forelimb-stump representation suppress the expression of reorganized hindlimb inputs to the region. A circuit model incorporating these and previous observations is presented and discussed.

Selective attention on representations in working memory: cognitive and neural mechanisms.

PubMed

Ku, Yixuan

2018-01-01

Selective attention and working memory are inter-dependent core cognitive functions. It is critical to allocate attention on selected targets during the capacity-limited working memory processes to fulfill the goal-directed behavior. The trends of research on both topics are increasing exponentially in recent years, and it is considered that selective attention and working memory share similar underlying neural mechanisms. Different types of attention orientation in working memory are introduced by distinctive cues, and the means using retrospective cues are strengthened currently as it is manipulating the representation in memory, instead of the perceptual representation. The cognitive and neural mechanisms of the retro-cue effects are further reviewed, as well as the potential molecular mechanism. The frontal-parietal network that is involved in both attention and working memory is also the neural candidate for attention orientation during working memory. Neural oscillations in the gamma and alpha/beta oscillations may respectively be employed for the feedforward and feedback information transfer between the sensory cortices and the association cortices. Dopamine and serotonin systems might interact with each other subserving the communication between memory and attention. In conclusion, representations which attention shifts towards are strengthened, while representations which attention moves away from are degraded. Studies on attention orientation during working memory indicates the flexibility of the processes of working memory, and the beneficial way that overcome the limited capacity of working memory.

Selective attention on representations in working memory: cognitive and neural mechanisms

PubMed Central

2018-01-01

Selective attention and working memory are inter-dependent core cognitive functions. It is critical to allocate attention on selected targets during the capacity-limited working memory processes to fulfill the goal-directed behavior. The trends of research on both topics are increasing exponentially in recent years, and it is considered that selective attention and working memory share similar underlying neural mechanisms. Different types of attention orientation in working memory are introduced by distinctive cues, and the means using retrospective cues are strengthened currently as it is manipulating the representation in memory, instead of the perceptual representation. The cognitive and neural mechanisms of the retro-cue effects are further reviewed, as well as the potential molecular mechanism. The frontal-parietal network that is involved in both attention and working memory is also the neural candidate for attention orientation during working memory. Neural oscillations in the gamma and alpha/beta oscillations may respectively be employed for the feedforward and feedback information transfer between the sensory cortices and the association cortices. Dopamine and serotonin systems might interact with each other subserving the communication between memory and attention. In conclusion, representations which attention shifts towards are strengthened, while representations which attention moves away from are degraded. Studies on attention orientation during working memory indicates the flexibility of the processes of working memory, and the beneficial way that overcome the limited capacity of working memory. PMID:29629245

Dependence and a Kantian conception of dignity as a value.

PubMed

Byers, Philippa

2016-02-01

Kantian moral concepts concerning respect for human dignity have played a central role in articulating ethical guidelines for medical practice and research, and for articulating some central positions within bioethical debates more generally. The most common of these Kantian moral concepts is the obligation to respect the dignity of patients and of human research subjects as autonomous, self-determining individuals. This article describes Kant's conceptual distinction between dignity and autonomy as values, and draws on the work of several contemporary Kantian philosophers who employ the distinction to make sense of some common moral intuitions, feelings, and norms. Drawing on this work, the article argues that the conceptual distinction between dignity and autonomy as values is indispensable in the context of considering our obligations to those who are dependent and vulnerable.

From Central Pattern Generator to Sensory Template in the Evolution of Birdsong

ERIC Educational Resources Information Center

Konishi, Masakazu

2010-01-01

Central nervous networks, be they a part of the human brain or a group of neurons in a snail, may be designed to produce distinct patterns of movement. Central pattern generators can account for the development and production of normal vocal signals without auditory feedback in non-songbirds. Songbirds need auditory feedback to develop and…

Local Adaptation of Central Policies: The Policymaking and Implementation of Compulsory Education for Migrant Children in China

ERIC Educational Resources Information Center

Wang, Lihua

2016-01-01

This article looks at the central and local governments' policymaking and implementation of compulsory education for migrant children in China. Three distinct models of policy implementation were identified through a case study approach. They indicated a selective adaptation of central policy objective and principles by the local governments and…

The Two-Level Theory of verb meaning: An approach to integrating the semantics of action with the mirror neuron system.

PubMed

Kemmerer, David; Gonzalez-Castillo, Javier

2010-01-01

Verbs have two separate levels of meaning. One level reflects the uniqueness of every verb and is called the "root". The other level consists of a more austere representation that is shared by all the verbs in a given class and is called the "event structure template". We explore the following hypotheses about how, with specific reference to the motor features of action verbs, these two distinct levels of semantic representation might correspond to two distinct levels of the mirror neuron system. Hypothesis 1: Root-level motor features of verb meaning are partially subserved by somatotopically mapped mirror neurons in the left primary motor and/or premotor cortices. Hypothesis 2: Template-level motor features of verb meaning are partially subserved by representationally more schematic mirror neurons in Brodmann area 44 of the left inferior frontal gyrus. Evidence has been accumulating in support of the general neuroanatomical claims made by these two hypotheses-namely, that each level of verb meaning is associated with the designated cortical areas. However, as yet no studies have satisfied all the criteria necessary to support the more specific neurobiological claims made by the two hypotheses-namely, that each level of verb meaning is associated with mirror neurons in the pertinent brain regions. This would require demonstrating that within those regions the same neuronal populations are engaged during (a) the linguistic processing of particular motor features of verb meaning, (b) the execution of actions with the corresponding motor features, and (c) the observation of actions with the corresponding motor features. 2008 Elsevier Inc. All rights reserved.

Vaunting the independent amateur: Scientific American and the representation of lay scientists.

PubMed

Johnston, Sean F

2018-04-01

This paper traces how media representations encouraged enthusiasts, youth and skilled volunteers to participate actively in science and technology during the twentieth century. It assesses how distinctive discourses about scientific amateurs positioned them with respect to professionals in shifting political and cultural environments. In particular, the account assesses the seminal role of a periodical, Scientific American magazine, in shaping and championing an enduring vision of autonomous scientific enthusiasms. Between the 1920s and 1970s, editors Albert G. Ingalls and Clair L. Stong shepherded generations of adult 'amateur scientists'. Their columns and books popularized a vision of independent non-professional research that celebrated the frugal ingenuity and skills of inveterate tinkerers. Some of these attributes have found more recent expression in present-day 'maker culture'. The topic consequently is relevant to the historiography of scientific practice, science popularization and science education. Its focus on independent non-professionals highlights political dimensions of agency and autonomy that have often been implicit for such historical (and contemporary) actors. The paper argues that the Scientific American template of adult scientific amateurism contrasted with other representations: those promoted by earlier periodicals and by a science education organization, Science Service, and by the national demands for recruiting scientific labour during and after the Second World War. The evidence indicates that advocates of the alternative models had distinctive goals and adapted their narrative tactics to reach their intended audiences, which typically were conceived as young persons requiring instruction or mentoring. By contrast, the monthly Scientific American columns established a long-lived and stable image of the independent lay scientist.

THE TWO-LEVEL THEORY OF VERB MEANING: AN APPROACH TO INTEGRATING THE SEMANTICS OF ACTION WITH THE MIRROR NEURON SYSTEM

PubMed Central

Kemmerer, David; Castillo, Javier Gonzalez

2010-01-01

Verbs have two separate levels of meaning. One level reflects the uniqueness of every verb and is called the “root.” The other level consists of a more austere representation that is shared by all the verbs in a given class and is called the “event structure template.” We explore the following hypotheses about how, with specific reference to the motor features of action verbs, these two distinct levels of semantic representation might correspond to two distinct levels of the mirror neuron system. Hypothesis 1: Root-level motor features of verb meaning are partially subserved by somatotopically mapped mirror neurons in the left primary motor and/or premotor cortices. Hypothesis 2: Template-level motor features of verb meaning are partially subserved by representationally more schematic mirror neurons in Brodmann area 44 of the left inferior frontal gyrus. Evidence has been accumulating in support of the general neuroanatomical claims made by these two hypotheses—namely, that each level of verb meaning is associated with the designated cortical areas. However, as yet no studies have satisfied all the criteria necessary to support the more specific neurobiological claims made by the two hypotheses—namely, that each level of verb meaning is associated with mirror neurons in the pertinent brain regions. This would require demonstrating that within those regions the same neuronal populations are engaged during (a) the linguistic processing of particular motor features of verb meaning, (b) the execution of actions with the corresponding motor features, and (c) the observation of actions with the corresponding motor features. PMID:18996582

A neural network model of causative actions.

PubMed

Lee-Hand, Jeremy; Knott, Alistair

2015-01-01

A common idea in models of action representation is that actions are represented in terms of their perceptual effects (see e.g., Prinz, 1997; Hommel et al., 2001; Sahin et al., 2007; Umiltà et al., 2008; Hommel, 2013). In this paper we extend existing models of effect-based action representations to account for a novel distinction. Some actions bring about effects that are independent events in their own right: for instance, if John smashes a cup, he brings about the event of the cup smashing. Other actions do not bring about such effects. For instance, if John grabs a cup, this action does not cause the cup to "do" anything: a grab action has well-defined perceptual effects, but these are not registered by the perceptual system that detects independent events involving external objects in the world. In our model, effect-based actions are implemented in several distinct neural circuits, which are organized into a hierarchy based on the complexity of their associated perceptual effects. The circuit at the top of this hierarchy is responsible for actions that bring about independently perceivable events. This circuit receives input from the perceptual module that recognizes arbitrary events taking place in the world, and learns movements that reliably cause such events. We assess our model against existing experimental observations about effect-based motor representations, and make some novel experimental predictions. We also consider the possibility that the "causative actions" circuit in our model can be identified with a motor pathway reported in other work, specializing in "functional" actions on manipulable tools (Bub et al., 2008; Binkofski and Buxbaum, 2013).

Illusory Memories of Emotionally Charged Words in Autism Spectrum Disorder: Further Evidence for Atypical Emotion Processing outside the Social Domain

ERIC Educational Resources Information Center

Gaigg, Sebastian B.; Bowler, Dermot M.

2009-01-01

Recent evidence suggests that individuals with ASD may not accumulate distinct representations of emotional information throughout development. On the basis of this observation we predicted that such individuals would not be any less likely to falsely remember emotionally significant as compared to neutral words when such "illusory memories" are…

Isolation and Distinctiveness in the Design of E-Learning Systems Influence User Preferences

ERIC Educational Resources Information Center

Al-Samarraie, Hosam; Selim, Hassan; Teo, Timothy; Zaqout, Fahed

2017-01-01

When faced with excessive detail in an online environment, typical users have difficulty processing all the elements of representation. This in turn creates cognitive overload, which narrows the user's focus to a few select items. In the context of e-learning, we translated this aspect as the learner's demand for a system that facilitates the…

Teaching Image Formation by Extended Light Sources: The Use of a Model Derived from the History of Science

ERIC Educational Resources Information Center

Dedes, Christos; Ravanis, Konstantinos

2009-01-01

This research, carried out in Greece on pupils aged 12-16, focuses on the transformation of their representations concerning light emission and image formation by extended light sources. The instructive process was carried out in two stages, each one having a different, distinct target set. During the first stage, the appropriate conflict…

Neural Evidence for a Distinction between Short-Term Memory and the Focus of Attention

ERIC Educational Resources Information Center

Lewis-Peacock, Jarrod A.; Drysdale, Andrew T.; Oberauer, Klaus; Postle, Bradley R.

2012-01-01

It is widely assumed that the short-term retention of information is accomplished via maintenance of an active neural trace. However, we demonstrate that memory can be preserved across a brief delay despite the apparent loss of sustained representations. Delay period activity may, in fact, reflect the focus of attention, rather than STM. We…

Developmental and Cognitive Perspectives on Humans' Sense of the Times of Past and Future Events

ERIC Educational Resources Information Center

Friedman, W.J.

2005-01-01

Mental time travel in human adults includes a sense of when past events occurred and future events are expected to occur. Studies with adults and children reveal that a number of distinct psychological processes contribute to a temporally differentiated sense of the past and future. Adults possess representations of multiple time patterns, and…

Differential Effects of Age-of-Acquisition for Concrete Nouns and Action Verbs: Evidence for Partly Distinct Representations?

ERIC Educational Resources Information Center

Boulenger, Veronique; Decoppet, Nathalie; Roy, Alice C.; Paulignan, Yves; Nazir, Tatjana A.

2007-01-01

There is growing evidence that words that are acquired early in life are processed faster and more accurately than words acquired later, even by adults. As neuropsychological and neuroimaging studies have implicated different brain networks in the processing of action verbs and concrete nouns, the present study was aimed at contrasting reaction…

Gender Representation in Contemporary Grade 10 Business Studies Textbooks in South Africa

ERIC Educational Resources Information Center

Maistry, Suriamurthee Moonsamy; Pillay, Preya

2014-01-01

There is a distinct attempt on the part of the state to reposition the textbook as a key teaching and learning resource in South African schools. While the textbook industry has responded to the growing demand for better quality textbooks and attempted to embrace the tenets of the country's Constitution, especially as it relates to the issue of…

Disentangling Neural Sources of the Motor Interference Effect in High Functioning Autism: An EEG-Study

ERIC Educational Resources Information Center

Deschrijver, Eliane; Wiersema, Jan R.; Brass, Marcel

2017-01-01

The role of imitation in autism spectrum disorder (ASD) is controversial. Researchers have argued that deficient control of self- and other-related motor representations (self-other distinction) might explain imitation difficulties. In a recent EEG study, we showed that control of imitation relies on high-level as well as on low-level cognitive…

Self-Face and Self-Body Recognition in Autism

ERIC Educational Resources Information Center

Gessaroli, Erica; Andreini, Veronica; Pellegri, Elena; Frassinetti, Francesca

2013-01-01

The advantage in responding to self vs. others' body and face-parts (the so called self-advantage) is considered to reflect the implicit access to the bodily self representation and has been studied in healthy and brain-damaged adults in previous studies. If the distinction of the self from others is a key aspect of social behaviour and is a…

The Representation and Processing of Familiar Faces in Dyslexia: Differences in Age of Acquisition Effects

ERIC Educational Resources Information Center

Smith-Spark, James H.; Moore, Viv

2009-01-01

Two under-explored areas of developmental dyslexia research, face naming and age of acquisition (AoA), were investigated. Eighteen dyslexic and 18 non-dyslexic university students named the faces of 50 well-known celebrities, matched for facial distinctiveness and familiarity. Twenty-five of the famous people were learned early in life, while the…

Viriato: a Fourier-Hermite spectral code for strongly magnetised fluid-kinetic plasma dynamics

NASA Astrophysics Data System (ADS)

Loureiro, Nuno; Dorland, William; Fazendeiro, Luis; Kanekar, Anjor; Mallet, Alfred; Zocco, Alessandro

2015-11-01

We report on the algorithms and numerical methods used in Viriato, a novel fluid-kinetic code that solves two distinct sets of equations: (i) the Kinetic Reduced Electron Heating Model equations [Zocco & Schekochihin, 2011] and (ii) the kinetic reduced MHD (KRMHD) equations [Schekochihin et al., 2009]. Two main applications of these equations are magnetised (Alfvnénic) plasma turbulence and magnetic reconnection. Viriato uses operator splitting to separate the dynamics parallel and perpendicular to the ambient magnetic field (assumed strong). Along the magnetic field, Viriato allows for either a second-order accurate MacCormack method or, for higher accuracy, a spectral-like scheme. Perpendicular to the field Viriato is pseudo-spectral, and the time integration is performed by means of an iterative predictor-corrector scheme. In addition, a distinctive feature of Viriato is its spectral representation of the parallel velocity-space dependence, achieved by means of a Hermite representation of the perturbed distribution function. A series of linear and nonlinear benchmarks and tests are presented, with focus on 3D decaying kinetic turbulence. Work partially supported by Fundação para a Ciência e Tecnologia via Grants UID/FIS/50010/2013 and IF/00530/2013.

Dopaminergic neurons encode a distributed, asymmetric representation of temperature in Drosophila.

PubMed

Tomchik, Seth M

2013-01-30

Dopaminergic circuits modulate a wide variety of innate and learned behaviors in animals, including olfactory associative learning, arousal, and temperature-preference behavior. It is not known whether distinct or overlapping sets of dopaminergic neurons modulate these behaviors. Here, I have functionally characterized the dopaminergic circuits innervating the Drosophila mushroom body with in vivo calcium imaging and conditional silencing of genetically defined subsets of neurons. Distinct subsets of PPL1 dopaminergic neurons innervating the vertical lobes of the mushroom body responded to decreases in temperature, but not increases, with rapidly adapting bursts of activity. PAM neurons innervating the horizontal lobes did not respond to temperature shifts. Ablation of the antennae and maxillary palps reduced, but did not eliminate, the responses. Genetic silencing of dopaminergic neurons innervating the vertical mushroom body lobes substantially reduced behavioral cold avoidance, but silencing smaller subsets of these neurons had no effect. These data demonstrate that overlapping dopaminergic circuits encode a broadly distributed, asymmetric representation of temperature that overlays regions implicated previously in learning, memory, and forgetting. Thus, diverse behaviors engage overlapping sets of dopaminergic neurons that encode multimodal stimuli and innervate a single anatomical target, the mushroom body.

Recruitment and Consolidation of Cell Assemblies for Words by Way of Hebbian Learning and Competition in a Multi-Layer Neural Network

PubMed Central

Garagnani, Max; Wennekers, Thomas; Pulvermüller, Friedemann

2009-01-01

Current cognitive theories postulate either localist representations of knowledge or fully overlapping, distributed ones. We use a connectionist model that closely replicates known anatomical properties of the cerebral cortex and neurophysiological principles to show that Hebbian learning in a multi-layer neural network leads to memory traces (cell assemblies) that are both distributed and anatomically distinct. Taking the example of word learning based on action-perception correlation, we document mechanisms underlying the emergence of these assemblies, especially (i) the recruitment of neurons and consolidation of connections defining the kernel of the assembly along with (ii) the pruning of the cell assembly’s halo (consisting of very weakly connected cells). We found that, whereas a learning rule mapping covariance led to significant overlap and merging of assemblies, a neurobiologically grounded synaptic plasticity rule with fixed LTP/LTD thresholds produced minimal overlap and prevented merging, exhibiting competitive learning behaviour. Our results are discussed in light of current theories of language and memory. As simulations with neurobiologically realistic neural networks demonstrate here spontaneous emergence of lexical representations that are both cortically dispersed and anatomically distinct, both localist and distributed cognitive accounts receive partial support. PMID:20396612

Recruitment and Consolidation of Cell Assemblies for Words by Way of Hebbian Learning and Competition in a Multi-Layer Neural Network.

PubMed

Garagnani, Max; Wennekers, Thomas; Pulvermüller, Friedemann

2009-06-01

Current cognitive theories postulate either localist representations of knowledge or fully overlapping, distributed ones. We use a connectionist model that closely replicates known anatomical properties of the cerebral cortex and neurophysiological principles to show that Hebbian learning in a multi-layer neural network leads to memory traces (cell assemblies) that are both distributed and anatomically distinct. Taking the example of word learning based on action-perception correlation, we document mechanisms underlying the emergence of these assemblies, especially (i) the recruitment of neurons and consolidation of connections defining the kernel of the assembly along with (ii) the pruning of the cell assembly's halo (consisting of very weakly connected cells). We found that, whereas a learning rule mapping covariance led to significant overlap and merging of assemblies, a neurobiologically grounded synaptic plasticity rule with fixed LTP/LTD thresholds produced minimal overlap and prevented merging, exhibiting competitive learning behaviour. Our results are discussed in light of current theories of language and memory. As simulations with neurobiologically realistic neural networks demonstrate here spontaneous emergence of lexical representations that are both cortically dispersed and anatomically distinct, both localist and distributed cognitive accounts receive partial support.

Reading Poverty.

ERIC Educational Resources Information Center

Shannon, Patrick

The central purpose of this book is to challenge current social constructions of poverty, reading education, and the putative relationship between the two. It explores how official and popular representations of poverty are bound to specific historical, social, and economic conditions of their own production. The book offers four stances of…

Pedagogical Implications of Postmodernism in Adult Literacy.

ERIC Educational Resources Information Center

Campbell, Pat

The literature on postmodernism and education agrees on postmodernism's central features. It emphasizes heterogeneity, difference, plurality, and the fragmentary. It is unified in its critique of the Enlightenment's positions--totality, unity, representational and objective concepts of knowledge and truth. The pedagogy of Paulo Freire intersects…

Identification of deficiencies in seasonal rainfall simulated by CMIP5 climate models

NASA Astrophysics Data System (ADS)

Dunning, Caroline M.; Allan, Richard P.; Black, Emily

2017-11-01

An objective technique for analysing seasonality, in terms of regime, progression and timing of the wet seasons, is applied in the evaluation of CMIP5 simulations across continental Africa. Atmosphere-only and coupled integrations capture the gross observed patterns of seasonal progression and give mean onset/cessation dates within 18 days of the observational dates for 11 of the 13 regions considered. Accurate representation of seasonality over central-southern Africa and West Africa (excluding the southern coastline) adds credence for future projected changes in seasonality here. However, coupled simulations exhibit timing biases over the Horn of Africa, with the long rains 20 days late on average. Although both sets of simulations detect biannual rainfall seasonal cycles for East and Central Africa, coupled simulations fail to capture the biannual regime over the southern West African coastline. This is linked with errors in the Gulf of Guinea sea surface temperature (SST) and deficient representation of the SST/rainfall relationship.

Subcluster mergers and galaxy infall in A2151

NASA Technical Reports Server (NTRS)

Bird, Christina M.; Davis, David S.; Beers, Timothy C.

1995-01-01

We have obtained a 12.5 ks image of the Hercules Cluster, A2151, with the ROSAT PSPC. Comparison of the optical and X-ray emission coincides with the highest-density peak in the distribution, and is bimodal. The northern subclummp, distinct in position and velocity, has no detectable X-ray gas. The eastern subclump, apparent in the optical contour map, is indistinguishable from the clump in velocity space, but is clearly visible in the X-ray image. X-ray spectra derived from the central peak of emission yield a best-fit temperature of 1.6 keV. The emission coincident with the eastern clump of galaxies is cooler, 0.8 keV, and is outside the 90% confidence intervals of the central peak temperature. We suggest that the eastern and central subclusters have recently undergone a merger event. The lack of X-ray emission to the north suggests that those galaxies do not form a physically distinct structure (i.e., they are not located within a distinct gravitational potential), but rather that they are falling into the cluster core along the filament defined by the Hercules Supercluster.

The ventral visual pathway: an expanded neural framework for the processing of object quality.

PubMed

Kravitz, Dwight J; Saleem, Kadharbatcha S; Baker, Chris I; Ungerleider, Leslie G; Mishkin, Mortimer

2013-01-01

Since the original characterization of the ventral visual pathway, our knowledge of its neuroanatomy, functional properties, and extrinsic targets has grown considerably. Here we synthesize this recent evidence and propose that the ventral pathway is best understood as a recurrent occipitotemporal network containing neural representations of object quality both utilized and constrained by at least six distinct cortical and subcortical systems. Each system serves its own specialized behavioral, cognitive, or affective function, collectively providing the raison d'être for the ventral visual pathway. This expanded framework contrasts with the depiction of the ventral visual pathway as a largely serial staged hierarchy culminating in singular object representations and more parsimoniously incorporates attentional, contextual, and feedback effects. Published by Elsevier Ltd.

Culture and its neurofunctional correlates when death is in mind.

PubMed

Graupmann, Verena; Peres, Isabella; Michaely, Tonia; Meindl, Thomas; Frey, Dieter; Reiser, Maximilian; Pöppel, Ernst; Fehse, Kai; Gutyrchik, Evgeny

2013-08-26

The human fear of death is marked by specific psychological reactions that affirm cultural belonging. Terror management theory explains this phenomenon with the symbolic immortality provided by collective meaning in culture. This coping has also been explained with the motive of maintaining a meaningful representation of the world. Here we show that neural patterns of activations corresponding to cultural worldview defense processes differed when images that affirmed participants' cultural heritage were preceded by death-related verbal primes versus verbal primes threatening meaning. Cultural content was drawn upon distinctly on a neural basis when facing death-related cognitions. The neural representation of cultural coping sheds light on the immediate mechanisms in compensating the human fear of death. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

FRIT characterized hierarchical kernel memory arrangement for multiband palmprint recognition

NASA Astrophysics Data System (ADS)

Kisku, Dakshina R.; Gupta, Phalguni; Sing, Jamuna K.

2015-10-01

In this paper, we present a hierarchical kernel associative memory (H-KAM) based computational model with Finite Ridgelet Transform (FRIT) representation for multispectral palmprint recognition. To characterize a multispectral palmprint image, the Finite Ridgelet Transform is used to achieve a very compact and distinctive representation of linear singularities while it also captures the singularities along lines and edges. The proposed system makes use of Finite Ridgelet Transform to represent multispectral palmprint image and it is then modeled by Kernel Associative Memories. Finally, the recognition scheme is thoroughly tested with a benchmarking multispectral palmprint database CASIA. For recognition purpose a Bayesian classifier is used. The experimental results exhibit robustness of the proposed system under different wavelengths of palm image.

GRAPES—Grounding representations in action, perception, and emotion systems: How object properties and categories are represented in the human brain

PubMed Central

Martin, Alex

2016-01-01

In this article, I discuss some of the latest functional neuroimaging findings on the organization of object concepts in the human brain. I argue that these data provide strong support for viewing concepts as the products of highly interactive neural circuits grounded in the action, perception, and emotion systems. The nodes of these circuits are defined by regions representing specific object properties (e.g., form, color, and motion) and thus are property-specific, rather than strictly modality-specific. How these circuits are modified by external and internal environmental demands, the distinction between representational content and format, and the grounding of abstract social concepts are also discussed. PMID:25968087

Developmental dyscalculia is related to visuo-spatial memory and inhibition impairment☆

PubMed Central

Szucs, Denes; Devine, Amy; Soltesz, Fruzsina; Nobes, Alison; Gabriel, Florence

2013-01-01

Developmental dyscalculia is thought to be a specific impairment of mathematics ability. Currently dominant cognitive neuroscience theories of developmental dyscalculia suggest that it originates from the impairment of the magnitude representation of the human brain, residing in the intraparietal sulcus, or from impaired connections between number symbols and the magnitude representation. However, behavioral research offers several alternative theories for developmental dyscalculia and neuro-imaging also suggests that impairments in developmental dyscalculia may be linked to disruptions of other functions of the intraparietal sulcus than the magnitude representation. Strikingly, the magnitude representation theory has never been explicitly contrasted with a range of alternatives in a systematic fashion. Here we have filled this gap by directly contrasting five alternative theories (magnitude representation, working memory, inhibition, attention and spatial processing) of developmental dyscalculia in 9–10-year-old primary school children. Participants were selected from a pool of 1004 children and took part in 16 tests and nine experiments. The dominant features of developmental dyscalculia are visuo-spatial working memory, visuo-spatial short-term memory and inhibitory function (interference suppression) impairment. We hypothesize that inhibition impairment is related to the disruption of central executive memory function. Potential problems of visuo-spatial processing and attentional function in developmental dyscalculia probably depend on short-term memory/working memory and inhibition impairments. The magnitude representation theory of developmental dyscalculia was not supported. PMID:23890692

A Knowledge-Based Representation Scheme for Environmental Science Models

NASA Technical Reports Server (NTRS)

Keller, Richard M.; Dungan, Jennifer L.; Lum, Henry, Jr. (Technical Monitor)

1994-01-01

One of the primary methods available for studying environmental phenomena is the construction and analysis of computational models. We have been studying how artificial intelligence techniques can be applied to assist in the development and use of environmental science models within the context of NASA-sponsored activities. We have identified several high-utility areas as potential targets for research and development: model development; data visualization, analysis, and interpretation; model publishing and reuse, training and education; and framing, posing, and answering questions. Central to progress on any of the above areas is a representation for environmental models that contains a great deal more information than is present in a traditional software implementation. In particular, a traditional software implementation is devoid of any semantic information that connects the code with the environmental context that forms the background for the modeling activity. Before we can build AI systems to assist in model development and usage, we must develop a representation for environmental models that adequately describes a model's semantics and explicitly represents the relationship between the code and the modeling task at hand. We have developed one such representation in conjunction with our work on the SIGMA (Scientists' Intelligent Graphical Modeling Assistant) environment. The key feature of the representation is that it provides a semantic grounding for the symbols in a set of modeling equations by linking those symbols to an explicit representation of the underlying environmental scenario.

A U.S. Geological Survey Data Standard (Specifications for representation of geographic point locations for information interchange)

USGS Publications Warehouse

,

1983-01-01

This standard establishes uniform formats for geographic point location data. Geographic point location refers to the use of a coordinate system to define the position of a point that may be on, above, or below the Earth's surface. It provides a means for representing these data in digital form for the purpose of interchanging information among data systems and improving clarity and accuracy of interpersonal communications. This document is an expansion and clarification of National Bureau of Standards FIPS PUB 70, issued October 24, 1980. There are minor editorial changes, plus the following additions and modifications: (I) The representation of latitude and longitude using radian measure was added. (2) Alternate 2 for Representation of Hemispheric Information was deleted. (3) Use of the maximum precision for all numerical values was emphasized. The Alternate Representation of Precision was deleted. (4) The length of the zone representation for the State Plane Coordinate System was standardized. (5) The term altitude was substituted for elevation throughout to conform with international usage. (6) Section 3, Specifications for Altitude Data, was expanded and upgraded significantly to the same level of detail as for the horizontal values. (7) A table delineating the coverage of Universal Transverse Mercator zones and the longitudes of the Central Meridians was added and the other tables renumbered. (8) The total length of the representation of point location data at maximum precision was standardized.

Dissociable neural correlates of contour completion and contour representation in illusory contour perception.

PubMed

Wu, Xiang; He, Sheng; Bushara, Khalaf; Zeng, Feiyan; Liu, Ying; Zhang, Daren

2012-10-01

Object recognition occurs even when environmental information is incomplete. Illusory contours (ICs), in which a contour is perceived though the contour edges are incomplete, have been extensively studied as an example of such a visual completion phenomenon. Despite the neural activity in response to ICs in visual cortical areas from low (V1 and V2) to high (LOC: the lateral occipital cortex) levels, the details of the neural processing underlying IC perception are largely not clarified. For example, how do the visual areas function in IC perception and how do they interact to archive the coherent contour perception? IC perception involves the process of completing the local discrete contour edges (contour completion) and the process of representing the global completed contour information (contour representation). Here, functional magnetic resonance imaging was used to dissociate contour completion and contour representation by varying each in opposite directions. The results show that the neural activity was stronger to stimuli with more contour completion than to stimuli with more contour representation in V1 and V2, which was the reverse of that in the LOC. When inspecting the neural activity change across the visual pathway, the activation remained high for the stimuli with more contour completion and increased for the stimuli with more contour representation. These results suggest distinct neural correlates of contour completion and contour representation, and the possible collaboration between the two processes during IC perception, indicating a neural connection between the discrete retinal input and the coherent visual percept. Copyright © 2011 Wiley Periodicals, Inc.

48 CFR 52.219-25 - Small Disadvantaged Business Participation Program-Disadvantaged Status and Reporting.

Code of Federal Regulations, 2012 CFR

2012-10-01

... disadvantaged business concern certified by the Small Business Administration by using the Central Contractor Registration database or by contacting the SBA's Office of Small Disadvantaged Business Certification and... Business Administration, the Contractor shall accept the subcontractor's written self-representation as a...

48 CFR 52.219-25 - Small Disadvantaged Business Participation Program-Disadvantaged Status and Reporting.

Code of Federal Regulations, 2011 CFR

2011-10-01

... disadvantaged business concern certified by the Small Business Administration by using the Central Contractor Registration database or by contacting the SBA's Office of Small Disadvantaged Business Certification and... Business Administration, the Contractor shall accept the subcontractor's written self-representation as a...

Educating the Developing Mind: Towards an Overarching Paradigm

ERIC Educational Resources Information Center

Demetriou, Andreas; Spanoudis, George; Mouyi, Antigoni

2011-01-01

This essay first summarizes an overarching theory of cognitive organization and development. This theory claims that the human mind involves (1) several specialized structural systems dealing with different domains of relations in the environment, (2) a central representational capacity system, (3) general inferential processes, and (4)…

Central pattern generator for vocalization: is there a vertebrate morphotype?

PubMed

Bass, Andrew H

2014-10-01

Animals that generate acoustic signals for social communication are faced with two essential tasks: generate a temporally precise signal and inform the auditory system about the occurrence of one's own sonic signal. Recent studies of sound producing fishes delineate a hindbrain network comprised of anatomically distinct compartments coding equally distinct neurophysiological properties that allow an organism to meet these behavioral demands. A set of neural characters comprising a vocal-sonic central pattern generator (CPG) morphotype is proposed for fishes and tetrapods that shares evolutionary developmental origins with pectoral appendage motor systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Central pattern generator for vocalization: Is there a vertebrate morphotype?

PubMed Central

Bass, Andrew H.

2014-01-01

Animals that generate acoustic signals for social communication are faced with two essential tasks: generate a temporally precise signal and inform the auditory system about the occurrence of one’s own sonic signal. Recent studies of sound producing fishes delineate a hindbrain network comprised of anatomically distinct compartments coding equally distinct neurophysiological properties that allow an organism to meet these behavioral demands. A set of neural characters comprising a vocal-sonic central pattern generator (CPG) morphotype is proposed for fishes and tetrapods that shares evolutionary developmental origins with pectoral appendage motor systems. PMID:25050813

Negativity Bounds for Weyl-Heisenberg Quasiprobability Representations

NASA Astrophysics Data System (ADS)

DeBrota, John B.; Fuchs, Christopher A.

2017-08-01

The appearance of negative terms in quasiprobability representations of quantum theory is known to be inevitable, and, due to its equivalence with the onset of contextuality, of central interest in quantum computation and information. Until recently, however, nothing has been known about how much negativity is necessary in a quasiprobability representation. Zhu (Phys Rev Lett 117 (12):120404, 2016) proved that the upper and lower bounds with respect to one type of negativity measure are saturated by quasiprobability representations which are in one-to-one correspondence with the elusive symmetric informationally complete quantum measurements (SICs). We define a family of negativity measures which includes Zhu's as a special case and consider another member of the family which we call "sum negativity." We prove a sufficient condition for local maxima in sum negativity and find exact global maxima in dimensions 3 and 4. Notably, we find that Zhu's result on the SICs does not generally extend to sum negativity, although the analogous result does hold in dimension 4. Finally, the Hoggar lines in dimension 8 make an appearance in a conjecture on sum negativity.

Thalamic amplification of cortical connectivity sustains attentional control

PubMed Central

Schmitt, L. Ian; Wimmer, Ralf D.; Nakajima, Miho; Happ, Michael; Mofakham, Sima; Halassa, Michael M.

2017-01-01

While interactions between the thalamus and cortex are critical for cognitive function1–3, the exact contribution of the thalamus to these interactions is often unclear. Recent studies have shown diverse connectivity patterns across the thalamus 4,5, but whether this diversity translates to thalamic functions beyond relaying information to or between cortical regions6 is unknown. Here, by investigating prefrontal cortical (PFC) representation of two rules used to guide attention, we find that the mediodorsal thalamus (MD) sustains these representations without relaying categorical information. Specifically, MD input amplifies local PFC connectivity, enabling rule-specific neural sequences to emerge and thereby maintain rule representations. Consistent with this notion, broadly enhancing PFC excitability diminishes rule specificity and behavioral performance, while enhancing MD excitability improves both. Overall, our results define a previously unknown principle in neuroscience; thalamic control of functional cortical connectivity. This function indicates that the thalamus plays much more central roles in cognition than previously thought. PMID:28467827

[The work of the intensive care nurse: a study on the social representations structure].

PubMed

Silva, Iranete Almeida Sousa; da Cruz, Enêde Andrade

2008-09-01

This study aims at characterizing the social representations of the nurse in the intensive care unit (ICU) by identifying the central core and the peripheral system. It was carried out in five ICUs from both public and philanthropic teaching, research and assistance hospitals in Salvador (Bahia, Brazil). Data were gathered from ninety nurses by means of free evocation from the phrase: nurse's work in an ICU and then processed with the EVOC software. Analysis was performed by building a four-digit chart based on the structural approach to the theory of social representations. Results point out stress, responsibility, integral care and gratification as the core elements. The peripheral system comprised personal and professional attitudes deemed necessary to perform the work. Therefore, it could be concluded that stress and responsible work are relieved by the gratifying feeling of providing integral care, which demands a range of personal and professional attitudes.

Angular velocity integration in a fly heading circuit.

PubMed

Turner-Evans, Daniel; Wegener, Stephanie; Rouault, Hervé; Franconville, Romain; Wolff, Tanya; Seelig, Johannes D; Druckmann, Shaul; Jayaraman, Vivek

2017-05-22

Many animals maintain an internal representation of their heading as they move through their surroundings. Such a compass representation was recently discovered in a neural population in the Drosophila melanogaster central complex, a brain region implicated in spatial navigation. Here, we use two-photon calcium imaging and electrophysiology in head-fixed walking flies to identify a different neural population that conjunctively encodes heading and angular velocity, and is excited selectively by turns in either the clockwise or counterclockwise direction. We show how these mirror-symmetric turn responses combine with the neurons' connectivity to the compass neurons to create an elegant mechanism for updating the fly's heading representation when the animal turns in darkness. This mechanism, which employs recurrent loops with an angular shift, bears a resemblance to those proposed in theoretical models for rodent head direction cells. Our results provide a striking example of structure matching function for a broadly relevant computation.

Sensations of skin infestation linked to abnormal frontolimbic brain reactivity and differences in self-representation.

PubMed

Eccles, J A; Garfinkel, S N; Harrison, N A; Ward, J; Taylor, R E; Bewley, A P; Critchley, H D

2015-10-01

Some patients experience skin sensations of infestation and contamination that are elusive to proximate dermatological explanation. We undertook a functional magnetic resonance imaging study of the brain to demonstrate, for the first time, that central processing of infestation-relevant stimuli is altered in patients with such abnormal skin sensations. We show differences in neural activity within amygdala, insula, middle temporal lobe and frontal cortices. Patients also demonstrated altered measures of self-representation, with poorer sensitivity to internal bodily (interoceptive) signals and greater susceptibility to take on an illusion of body ownership: the rubber hand illusion. Together, these findings highlight a potential model for the maintenance of abnormal skin sensations, encompassing heightened threat processing within amygdala, increased salience of skin representations within insula and compromised prefrontal capacity for self-regulation and appraisal. Copyright © 2015 Elsevier Ltd. All rights reserved.

Parallel, multi-stage processing of colors, faces and shapes in macaque inferior temporal cortex

PubMed Central

Lafer-Sousa, Rosa; Conway, Bevil R.

2014-01-01

Visual-object processing culminates in inferior temporal (IT) cortex. To assess the organization of IT, we measured fMRI responses in alert monkey to achromatic images (faces, fruit, bodies, places) and colored gratings. IT contained multiple color-biased regions, which were typically ventral to face patches and, remarkably, yoked to them, spaced regularly at four locations predicted by known anatomy. Color and face selectivity increased for more anterior regions, indicative of a broad hierarchical arrangement. Responses to non-face shapes were found across IT, but were stronger outside color-biased regions and face patches, consistent with multiple parallel streams. IT also contained multiple coarse eccentricity maps: face patches overlapped central representations; color-biased regions spanned mid-peripheral representations; and place-biased regions overlapped peripheral representations. These results suggest that IT comprises parallel, multi-stage processing networks subject to one organizing principle. PMID:24141314

Human Memory Limitations in Multi-Object Tracking.

DTIC Science & Technology

1982-06-01

processing concepts of Norman (1968) and Atkinson and Shiffrin (1968), and from the " levels of processing " formulation of Craik and Lockhart ...distinct memory representations that result from different levels of processing . Craik and Lockhart (1972) have argued convincingly for a process -oriented...learning and motivation (Vol. 2). New York: Academic Press, 1968, pp. 89-105. Craik , F. I. M., & Lockhart , R. S. Levels of processing

A Construct for Describing Software Development Risks

DTIC Science & Technology

1994-07-01

consequences during any risk identification process. It is more important and expedient to capture the conditions since the basic statement of conse ...chain of causal events. The contrast between the exploration of conditions rather than conse - quences in risk identification is similar to that of...extent that a general con - dition has a multiplicity of individual characteristics. In the CTC representation, these distinct risks can share common

Can I Reach That Sticker? Preschoolers' Practical Judgments about Their Own and Others' Body Size

ERIC Educational Resources Information Center

Dunphy-Lelii, Sarah; Hooley, Merrilyn; McGivern, Lisa; Skouteris, Helen; Cox, Rachael

2014-01-01

Research to date has focused mostly on children's representation of their physical self as a prelude to the development of a theory of mind (ToM) and on their understanding of the self as distinct from others over time. Whether children approaching the well-known age of ToM mastery are also accurately appraising their own "body's"…

Young Children's Rapid Learning about Artifacts

ERIC Educational Resources Information Center

Casler, Krista; Kelemen, Deborah

2005-01-01

Tool use is central to interdisciplinary debates about the evolution and distinctiveness of human intelligence, yet little is actually known about how human conceptions of artifacts develop. Results across these two studies show that even 2-year-olds approach artifacts in ways distinct from captive tool-using monkeys. Contrary to adult intuition,…

Nekrasov and Argyres-Douglas theories in spherical Hecke algebra representation

NASA Astrophysics Data System (ADS)

Rim, Chaiho; Zhang, Hong

2017-06-01

AGT conjecture connects Nekrasov instanton partition function of 4D quiver gauge theory with 2D Liouville conformal blocks. We re-investigate this connection using the central extension of spherical Hecke algebra in q-coordinate representation, q being the instanton expansion parameter. Based on AFLT basis together with intertwiners we construct gauge conformal state and demonstrate its equivalence to the Liouville conformal state, with careful attention to the proper scaling behavior of the state. Using the colliding limit of regular states, we obtain the formal expression of irregular conformal states corresponding to Argyres-Douglas theory, which involves summation of functions over Young diagrams.

Developing Knowledge of Nonadjacent Dependencies

ERIC Educational Resources Information Center

Culbertson, Jennifer; Koulaguina, Elena; Gonzalez-Gomez, Nayeli; Legendre, Géraldine; Nazzi, Thierry

2016-01-01

Characterizing the nature of linguistic representations and how they emerge during early development is a central goal in the cognitive science of language. One area in which this development plays out is in the acquisition of dependencies--relationships between co-occurring elements in a word, phrase, or sentence. These dependencies often involve…

Infants' Meaning-Making and the Development of Mental Health Problems

ERIC Educational Resources Information Center

Tronick, Ed; Beeghly, Marjorie

2011-01-01

We argue that infant meaning-making processes are a central mechanism governing both typical and pathological outcomes. Infants, as open dynamic systems, must constantly garner information to increase their complexity and coherence. They fulfill this demand by making nonverbal "meaning"--affects, movements, representations--about themselves in…

Application of Cognitive Science Principles: Instructional Heuristics and Mechanisms for Use.

ERIC Educational Resources Information Center

Montague, William E.

Cognitive science is briefly reviewed, and its implications for instructional design are discussed. The application of cognitive science to instruction requires knowledge of cognitive science, the subject content taught, and the system in which the instruction is imbedded. The central concept of cognitive science is mental representation--the…

New Evidence for Morphological Errors in Deep Dyslexia

ERIC Educational Resources Information Center

Rastle, Kathleen; Tyler, Lorraine K.; Marslen-Wilson, William

2006-01-01

Morphological errors in reading aloud (e.g., "sexist" [right arrow] "sexy") are a central feature of the symptom-complex known as deep dyslexia, and have historically been viewed as evidence that representations at some level of the reading system are morphologically structured. However, it has been proposed (Funnell, 1987) that morphological…

Memory, Childhood and Exile: Self-Representation in Post-Colonial Writing.

ERIC Educational Resources Information Center

Sharrad, Paul

1990-01-01

Using the works of writers like Thomas Wolfe, Christopher Koch, Raja Rao, and Albert Wendt, it is demonstrated that memory is a central element in postcolonial narratives and is associated with two important domains of cognition--recall of childhood and awareness of exile. (57 references) (JL)

Probing for Reasons: Presentations, Questions, Phases

ERIC Educational Resources Information Center

Morris, Kellyn Farlow; Speiser, Bob

2010-01-01

This paper reports on a research study based on data from experimental teaching. Undergraduate dance majors were invited, through real-world problem tasks that raised central conceptual issues, to invent major ideas of calculus. This study focuses on work and thinking by these students, as they sought to build key ideas, representations and…

Differential Lexical Predictors of Reading Comprehension in Fourth Graders

ERIC Educational Resources Information Center

Swart, Nicole M.; Muijselaar, Marloes M. L.; Steenbeek-Planting, Esther G.; Droop, Mienke; de Jong, Peter F.; Verhoeven, L.

2017-01-01

The mental lexicon plays a central role in reading comprehension (Perfetti & Stafura, 2014). It encompasses the number of lexical entries in spoken and written language (vocabulary breadth), the semantic quality of these entries (vocabulary depth), and the connection strength between lexical representations (semantic relatedness); as such, it…

The "No Crossing Constraint" in Autosegmental Phonology.

ERIC Educational Resources Information Center

Coleman, John; Local, John

A discussion of autosegmental phonology (AP), a theory of phonological representation that uses graphs rather than strings as the central data structure, considers its principal constraint, the "No Crossing Constraint" (NCC). The NCC is the statement that in a well-formed autosegmental diagram, lines of association may not cross. After…

Toward High-Performance Communications Interfaces for Science Problem Solving

ERIC Educational Resources Information Center

Oviatt, Sharon L.; Cohen, Adrienne O.

2010-01-01

From a theoretical viewpoint, educational interfaces that facilitate communicative actions involving representations central to a domain can maximize students' effort associated with constructing new schemas. In addition, interfaces that minimize working memory demands due to the interface per se, for example by mimicking existing non-digital work…

Rural Health Issues. Keynote Address.

ERIC Educational Resources Information Center

Hart, Gary

Medical students that come from rural areas are more likely to return to rural areas to practice, but rural students apply for medical school at half the rate of urban students. Factors that contribute to this problem are the lack of rural representation on medical school selection committees; centralization of medical education facilities in…

All for one but not one for all: how multiple number representations are recruited in one numerical task.

PubMed

Wood, Guilherme; Nuerk, Hans-Christoph; Moeller, Korbinian; Geppert, Barbara; Schnitker, Ralph; Weber, Jochen; Willmes, Klaus

2008-01-02

Number processing recruits a complex network of multiple numerical representations. Usually the components of this network are examined in a between-task approach with the disadvantage of relying upon different instructions, tasks, and inhomogeneous stimulus sets across different studies. A within-task approach may avoid these disadvantages and access involved numerical representations more specifically. In the present study we employed a within-task approach to investigate numerical representations activated in the number bisection task (NBT) using parametric rapid event-related fMRI. Participants were to judge whether the central number of a triplet was also its arithmetic mean (e.g. 23_26_29) or not (e.g. 23_25_29). Activation in the left inferior parietal cortex was associated with the deployment of arithmetic fact knowledge, while activation of the intraparietal cortex indicated more intense magnitude processing, instrumental aspects of calculation and integration of the base-10 structure of two-digit numbers. These results replicate evidence from the literature. Furthermore, activation in the dorsolateral and ventrolateral prefrontal cortex revealed mechanisms of feature monitoring and inhibition as well as allocation of cognitive resources recruited to solve a specific triplet. We conclude that the network of numerical representations should rather be studied in a within-task approach than in varying between-task approaches.

Attachment representations among substance-abusing women in transition to motherhood: implications for prenatal emotions and mother-infant interaction.

PubMed

Isosävi, Sanna; Flykt, Marjo; Belt, Ritva; Posa, Tiina; Kuittinen, Saija; Puura, Kaija; Punamäki, Raija-Leena

2016-08-01

We studied how attachment representations contribute to central components of transition to motherhood, prenatal emotion processing (EP) and emotional availability (EA) of mother-infant interaction, and whether there are group specific differences. Participants were 51 treatment-enrolled substance-abusing (SA) mothers and their infants and 50 non-using comparison dyads with obstetric risk. Mother's attachment representations (AAI) and EP were assessed prenatally and EA when infants were four months. Results showed that autonomous attachment only had a buffering effect on prenatal EP among comparisons. All SA mothers showed more dysfunctional EP than comparisons and, contrary to comparisons, autonomous SA mothers reported more negative cognitive appraisals and less meta-evaluation of emotions than dismissing SA mothers. Preoccupied SA mothers showed high negative cognitive appraisals, suggesting under-regulation of emotions. Attachment representations were not associated with EA in either group; rather, SA status contributed to global risk in the relationship. Surprisingly, autonomous SA mothers showed a tendency towards intrusiveness. We propose that obstetric risk among comparisons and adverse relational experiences among almost all SA mothers might override the protective role of mother's autonomous representations for dyadic interaction. We conclude that prenatal emotional turbulence and high interaction risk of all SA mothers calls for holistic treatment for the dyad.

Mental Imagery Scale: a new measurement tool to assess structural features of mental representations

NASA Astrophysics Data System (ADS)

D'Ercole, Martina; Castelli, Paolo; Giannini, Anna Maria; Sbrilli, Antonella

2010-05-01

Mental imagery is a quasi-perceptual experience which resembles perceptual experience, but occurring without (appropriate) external stimuli. It is a form of mental representation and is often considered centrally involved in visuo-spatial reasoning and inventive and creative thought. Although imagery ability is assumed to be functionally independent of verbal systems, it is still considered to interact with verbal representations, enabling objects to be named and names to evoke images. In literature, most measurement tools for evaluating imagery capacity are self-report instruments focusing on differences in individuals. In the present work, we applied a Mental Imagery Scale (MIS) to mental images derived from verbal descriptions in order to assess the structural features of such mental representations. This is a key theme for those disciplines which need to turn objects and representations into words and vice versa, such as art or architectural didactics. To this aim, an MIS questionnaire was administered to 262 participants. The questionnaire, originally consisting of a 33-item 5-step Likert scale, was reduced to 28 items covering six areas: (1) Image Formation Speed, (2) Permanence/Stability, (3) Dimensions, (4) Level of Detail/Grain, (5) Distance and (6) Depth of Field or Perspective. Factor analysis confirmed our six-factor hypothesis underlying the 28 items.

Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region

PubMed Central

Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

2015-01-01

The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

Chemical mixing model studies of lunar orbital geochemical data - Apollo 16 and 17 highlands compositions

NASA Technical Reports Server (NTRS)

Spudis, P. D.; Hawke, B. R.

1982-01-01

Chemical mixing model studies of lunar geochemical data for the central and Taurus-Littrow lunar highlands were performed utilizing pristine highland rock types as end member compositions. The central highlands show considerable diversity in composition; anorthosite is the principal rock type in the Apollo 16/Descartes region, while norite predominates in the highlands west of the landing site. This change in crustal composition is coincident with a major color boundary seen in earth-based multispectral data and probably represents the presence of distinct geochemical provinces within the central highlands. The Taurus-Littrow highlands are dominated by norite; anorthosite is far less abundant than in the central highlands. This suggests that the impact target for the Serenitatis basin was different than that of the Nectaris basin and further strengthens the hypothesis that the lunar highlands are petrologically heterogeneous on a regional basis. It is suggested that the lunar highlands should be viewed in terms of geochemical provinces that have undergone distinct and complex igneous and impact histories.

Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region.

PubMed

Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

2015-11-05

The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis.

Do Public Involvement Activities in Biomedical Research and Innovation Recruit Representatively? A Systematic Qualitative Review.

PubMed

Lander, Jonas; Hainz, Tobias; Hirschberg, Irene; Bossert, Sabine; Strech, Daniel

2016-01-01

Public involvement activities (PIAs) may contribute to the governance of ethically challenging biomedical research and innovation by informing, consulting with and engaging the public in developments and decision-making processes. For PIAs to capture a population's preferences (e.g. on issues in whole genome sequencing, biobanks or genome editing), a central methodological requirement is to involve a sufficiently representative subgroup of the general public. While the existing literature focusses on theoretical and normative aspects of 'representation', this study assesses empirically how such considerations are implemented in practice. It evaluates how PIA reports describe representation objectives, the recruitment process and levels of representation achieved. PIA reports were included from a systematic literature search if they directly reported a PIA conducted in a relevant discipline such as genomics, biobanks, biotechnology or others. PIA reports were analyzed with thematic text analysis. The text analysis was guided by an assessment matrix based on PIA-specific guidelines and frameworks. We included 46 relevant reports, most focusing on issues in genomics. 27 reports (59%) explicitly described representation objectives, though mostly without adjusting eligibility criteria and recruiting methods to the specific objective. 11 reports (24%) explicitly reported to have achieved the intended representation; the rest either reported failure or were silent on this issue. Representation of study samples in PIAs in biomedical research and innovation is currently not reported systematically. Improved reporting on representation would not only improve the validity and value of PIAs, but could also contribute to PIA results being used more often in relevant policy and decision-making processes. © 2016 S. Karger AG, Basel.