Search results for "REPRESENTATION"
showing 10 items of 1710 documents
Prismatic adaptation effects on spatial representation of time in neglect patients
2011
Abstract Processing of temporal information may require the use of spatial attention to represent time along a mental time line. We used prismatic adaptation (PA) to explore the contribution of spatial attention to the spatial representation of time in right brain damaged patients with and without neglect of left space and in age-matched healthy controls. Right brain damaged patients presented time underestimation deficits, that were significantly greater in patients with neglect than in patients without neglect. PA inducing leftward attentional deviation reduced time underestimation deficit in patients with neglect. The results support the hypothesis that a right hemispheric network has a …
Masked identity priming reflects an encoding advantage in developing readers.
2019
Abstract The masked priming technique is widely used to explore the early moments of letter and word identification. Although this technique is increasingly used in experiments with young readers, the mechanism in play during masked priming with early readers has not yet been fully explored. We investigated the masked priming effects from a modeling perspective; we instantiated competing theories as data models (using Bayes factors) and as a computational model (diffusion model). We carried out a masked priming experiment using identity primes with second- and fourth-grade participants, and we analyzed the data through an evidence accumulation model lens. The priming effect manifests as a s…
Space representation in children with dyslexia and children without dyslexia: Contribution of line bisection and circle centering tasks
2013
International audience; Line bisection tasks (different space locations and different line lengths) and circle centering tasks (visuo-proprioceptive and proprioceptive explorations, with left or right starting positions) were used to investigate space representation in children with dyslexia and children without dyslexia. In line bisection, children with dyslexia showed a significant rightward bias for central and right-sided locations and a leftward bias for left-sided location. Furthermore, the spatial context processing was asymmetrically more efficient in the left space. In children without dyslexia, no significant bias was observed in central lines but the spatial context processing wa…
The Relation between Geometry and Time in Mental Actions
2012
Mental imagery is a cognitive tool that helps humans take decisions by simulating past and future events. The hypothesis has been advanced that there is a functional equivalence between actual and mental movements. Yet, we do not know whether there are any limitations to its validity even in terms of some fundamental features of actual movements, such as the relationship between space and time. Although it is impossible to directly measure the spatiotemporal features of mental actions, an indirect investigation can be conducted by taking advantage of the constraints existing in planar drawing movements and described by the two-thirds power law (2/3PL). This kinematic law describes one of th…
Self-Generated Explanations on the Question Demands are not Always Helpful
2013
AbstractThis study had two main purposes. First, to measure high-school students’ task model representation under the instruction to self-explain questions; second, to test the effects of self-generated explanations on task-demands understanding and performance on questions. We designed a simple experimental situation where high-school students were asked to read two texts and answer questions. Only in half of the questions students were required to self-explain with their own words what the question was asking them for before answering. Contrary to our expectations, self-explaining the questions did not significantly affect skilled comprehenders, whereas it hindered performance in less-ski…
Multivariate data handling in the study of rat behavior: an integrated approach.
2009
The aim of the present article is to provide a methodological description of various approaches to multivariate data handling in the study of rodent behavior. To this purpose, 42 male Wistar rats were tested in an open field, and their behavior was recorded through a digital video camera for a subsequent analysis by means of a software coder. After a preliminary evaluation of descriptive features such as durations and percent distributions, we carried out different kinds of multivariate approaches represented by stochastic, cluster, adjusted residual, and T-pattern analyses. In the attempt to depict behavior in a straightforward way, the results of each analysis were graphically illustrated…
Extended Granger causality: a new tool to identify the structure of physiological networks.
2015
Granger causality (GC) is a very popular tool for assessing the presence of directional interactions between two time series of a multivariate data set. In its original formulation, GC does not account for zero-lag correlations possibly existing between the observed time series. In the present study we compare the GC with a novel measure, termed extended GC (eGC), able to capture instantaneous causal relationships. We present a two-step procedure for the practical estimation of eGC based on first detecting the existence of zero-lag correlations, and then assigning them to one of the two possible causal directions using pairwise measures of non-Gaussianity. The proposed method was validated …
Is VIRTU4L larger than VIR7UAL? Automatic processing of number quantity and lexical representations in leet words.
2015
Recent research has shown that leet words (i.e., words in which some of the letters are replaced by visually similar digits; e.g., VIRTU4L) can be processed as their base words without much cost. However, it remains unclear whether the digits inserted in leet words are simply processed as letters or whether they are simultaneously processed as numbers (i.e., in terms of access to their quantity representation). To address this question, we conducted two experiments that examined the size congruity effect (i.e., when comparisons of the physical size of numbers are affected by their numerical magnitudes) in a physical-size judgment task. Participants were presented with pairs of leet words th…
Initial information prior to movement onset influences kinematics of upward arm pointing movements
2016
International audience; To elaborate a motor plan and perform online control in the gravity field, the brain relies on priors and multisensory integration of information. In particular, afferent and efferent inputs related to the initial state are thought to convey sensorimotor information to plan the upcoming action. Yet it is still unclear to what extent these cues impact motor planning. Here we examined the role of initial information on the planning and execution of arm movements. Participants performed upward arm movements around the shoulder at three speeds and in two arm conditions. In the first condition, the arm was outstretched horizontally and required a significant muscular comm…
Temporal stability and representational distinctiveness: Key functions of orthographic working memory
2011
A primary goal of working memory research has been to understand the mechanisms that permit working memory systems to effectively maintain the identity and order of the elements held in memory for sufficient time as to allow for their selection and transfer to subsequent processing stages. Based on the performance of two individuals with acquired dysgraphia affecting orthographic working memory (WM; the graphemic buffer), we present evidence of two distinct and dissociable functions of orthographic WM. One function is responsible for maintaining the temporal stability of letters held in orthographic WM, while the other is responsible for maintaining their representational distinctiveness. T…