Search results for "present"
showing 10 items of 3598 documents
Mentally represented motor actions in normal aging. I. Age effects on the temporal features of overt and covert execution of actions.
2005
The present study examines the temporal features of overt and covert actions as a function of normal aging. In the first experiment, we tested three motor tasks (walking, sit-stand-sit, arm pointing) that did not imply any particular spatiotemporal constraints, and we compared the duration of their overt and covert execution in three different groups of age (mean ages: 22.5, 66.2 and 73.4 years). We found that the ability of generating motor images did not differentiate elderly subjects from young subjects. Precisely, regarding overt and covert durations, subjects presented similarities for the walking and pointing tasks and dissimilarities for the stand-sit-stand task. Furthermore, the tim…
Age slowing down in detection and visual discrimination under varying presentation times
2017
[EN] The reaction time has been described as a measure of perception, decision making, and other cognitive processes. The aim of this work is to examine agerelated changes in executive functions in terms of demand load under varying presentation times. Two tasks were employed where a signal detection and a discrimination task were performed by young and older university students. Furthermore, a characterization of the response time distribution by an exGaussian fit was carried out. The results indicated that the older participants were slower than the younger ones in signal detection and discrimination. Moreover, the differences between both processes for the older participants were higher,…
Learning-induced neural plasticity of speech processing before birth
2013
Learning, the foundation of adaptive and intelligent behavior, is based on plastic changes in neural assemblies, reflected by the modulation of electric brain responses. In infancy, auditory learning implicates the formation and strengthening of neural long-term memory traces, improving discrimination skills, in particular those forming the prerequisites for speech perception and understanding. Although previous behavioral observations show that newborns react differentially to unfamiliar sounds vs. familiar sound material that they were exposed to as fetuses, the neural basis of fetal learning has not thus far been investigated. Here we demonstrate direct neural correlates of human fetal l…
ERP correlates of transposed-letter similarity effects: Are consonants processed differently from vowels?
2007
Recent research has shown that pseudowords created by transposing letters are very effective for activating the lexical representation of their base words (e.g., relovution activates REVOLUTION). Furthermore, pseudoword transpositions of consonants are more similar to their corresponding base words than the transposition of vowels. We report one experiment using pseudowords created by the transposition of two consonants, two vowels, and their corresponding control conditions (i.e., the replacement of two consonants or two vowels) in a lexical decision task while Event Related Potentials (ERPs) were recorded. The results showed a modulation of the amplitude of the N400 component as a functio…
The Temporal Structure of Vertical Arm Movements
2011
Import JabRef | WosArea Life Sciences and Biomedicine - Other Topics; International audience; The present study investigates how the CNS deals with the omnipresent force of gravity during arm motor planning. Previous studies have reported direction-dependent kinematic differences in the vertical plane; notably, acceleration duration was greater during a downward than an upward arm movement. Although the analysis of acceleration and deceleration phases has permitted to explore the integration of gravity force, further investigation is necessary to conclude whether feedforward or feedback control processes are at the origin of this incorporation. We considered that a more detailed analysis of…
CATCHING FALLING OBJECTS: THE ROLE OF THE CEREBELLUM IN PROCESSING SENSORY-MOTOR ERRORS THAT MAY INFLUENCE UPDATING OF FEEDFORWARD COMMANDS. AN fMRI …
2011
Import JabRef | WosArea Neurosciences and Neurology; International audience; The human motor system continuously adapts to changes in the environment by comparing differences between the brain's predicted outcome of a certain behavior and the observed outcome. This discrepancy signal triggers a sensory-motor error and it is assumed that the cerebellum is a key structure in updating this error and associated feedforward commands. Using fMRI, the aim of the present study was to determine the main cerebellar structures that are involved in the processing of sensory-motor errors and in updating feedforward commands when simply catching a falling ball without displacement of the hand. Subjects o…
Identification of NM23-H2 as a tumour-associated antigen in chronic myeloid leukaemia.
2008
Therapeutic effects of haematopoietic stem cell transplantation are not limited to maximal chemoradiotherapy and subsequent bone marrow regeneration, but include specific as well as unspecific immune reactions known as graft-versus-leukaemia (GvL) effects. Specific immune reactions are likely to be particularly relevant to the long-term treatment of diseases, such as chronic myeloid leukaemia (CML), in which residual cells may remain quiescent and unresponsive to cytotoxic and molecular therapies for long periods of time. Specific GvL effects result from the expression on leukaemic cells of specific tumour-associated antigens (TAAs) in the context of HLA proteins. As human leukocyte antigen…
Is an attention-based associative account of adjacent and nonadjacent dependency learning valid?
2014
Pacton and Perruchet (2008) reported that participants who were asked to process adjacent elements located within a sequence of digits learned adjacent dependencies but did not learn nonadjacent dependencies and conversely, participants who were asked to process nonadjacent digits learned nonadjacent dependencies but did not learn adjacent dependencies. In the present study, we showed that when participants were simply asked to read aloud the same sequences of digits, a task demand that did not require the intentional processing of specific elements as in standard statistical learning tasks, only adjacent dependencies were learned. The very same pattern was observed when digits were replace…
LOW-RANK APPROXIMATION BASED NON-NEGATIVE MULTI-WAY ARRAY DECOMPOSITION ON EVENT-RELATED POTENTIALS
2014
Non-negative tensor factorization (NTF) has been successfully applied to analyze event-related potentials (ERPs), and shown superiority in terms of capturing multi-domain features. However, the time-frequency representation of ERPs by higher-order tensors are usually large-scale, which prevents the popularity of most tensor factorization algorithms. To overcome this issue, we introduce a non-negative canonical polyadic decomposition (NCPD) based on low-rank approximation (LRA) and hierarchical alternating least square (HALS) techniques. We applied NCPD (LRAHALS and benchmark HALS) and CPD to extract multi-domain features of a visual ERP. The features and components extracted by LRAHALS NCP…
Distinct neural-behavioral correspondence within face processing and attention networks for the composite face effect
2022
The composite face effect (CFE) is recognized as a hallmark for holistic face processing, but our knowledge remains sparse about its cognitive and neural loci. Using functional magnetic resonance imaging with independent localizer and complete composite face task, we here investigated its neural-behavioral correspondence within face processing and attention networks. Complementing classical comparisons, we adopted a dimensional reduction approach to explore the core cognitive constructs of the behavioral CFE measurement. Our univariate analyses found an alignment effect in regions associated with both the extended face processing network and attention networks. Further representational simi…