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showing 10 items of 4997 documents
From algorithmic computing to direct retrieval: Evidence from number and alphabetic arithmetic in children and adults
1998
A number of theories of mental arithmetic suggest that the ability to solve simple addition and subtraction problems develops from an algorithmic strategy toward a strategy based on the direct retrieval of the result from memory. In the experiment presented here, 2nd and 12th graders were asked to solve two tasks of number and alphabet arithmetic. The subjects transformed series of 1 to 4 numbers or letters (item span) by adding or subtracting an operand varying from 1 to 4 (operation span). Although both the item and operation span were associated with major and identical effects in the case of both numbers and letters at 2nd grade, such effects were clearly observable only in the case of …
Immediate transfer of synesthesia to a novel inducer.
2009
In synesthesia, a certain stimulus (e.g. grapheme) is associated automatically and consistently with a stable perceptual-like experience (e.g. color). These associations are acquired in early childhood and remain robust throughout the lifetime. Synesthetic associations can transfer to novel inducers in adulthood as one learns a second language that uses another writing system. However, it is not known how long this transfer takes. We found that grapheme-color associations can transfer to novel graphemes after only a 10-minute writing exercise. Most subjects experienced synesthetic associations immediately after learning a new Glagolitic grapheme. Using a Stroop task, we provide objective ev…
The hippocampus is required for short-term topographical memory in humans.
2007
The hippocampus plays a crucial role within the neural systems for long-term memory, but little if any role in the short-term retention of some types of stimuli. Nonetheless, the hippocampus may be specialized for allocentric topographical processing, which impacts on short-term memory or even perception. To investigate this we developed performance-matched tests of perception (match-to-sample) and short-term memory (2 s delayed-match-to-sample) for the topography and for the nonspatial aspects of visual scenes. Four patients with focal hippocampal damage and one with more extensive damage, including right parahippocampal gyrus, were tested. All five patients showed impaired topographical m…
Working Memory in Children: A Time-Constrained Functioning Similar to Adults
2009
International audience; Within the Time-Based Resource-Sharing (TBRS) model, we tested a new conception of the relationships between processing and storage in which the core mechanisms of WM are time constrained. However, our previous studies were restricted to adults. The present study aimed at demonstrating that these mechanisms are present and functional before adulthood. For this purpose, we investigated the effect on maintenance of the duration of the attentional capture induced by processing. In two experiments using computer-paced WM span tasks, 10- year-old children were asked to maintain letters while performing spatial location judgments. The duration of this processing was manipu…
LOW-DOSE INTERLEUKIN-2 INDUCES SYSTEMIC IMMUNE RESPONSES AGAINST HBsAg IN IMMUNODEFICIENT NON-RESPONDERS TO HEPATITIS B VACCINATION
1989
Abstract A metabolic monocyte defect appears to correlate with non-responsiveness to hepatitis B vaccine in many patients on haemodialysis. This defect prevents production of interleukin-2 during T-cell activation after antigen contact. Receptors for interleukin-2 are, however, expressed in greater numbers than in healthy subjects or uraemic responders to hepatitis B vaccination. In this study, ten uraemic patients, previous non-responders to vaccination against hepatitis B, were revaccinated with the same vaccine combined with one intramuscular injection (2·5 × 10 5 U) of natural human interleukin-2. Systemic production of antibodies against hepatitis B surface antigen was initiated in tho…
Excitability of subcortical motor circuits in Go/noGo and forced choice reaction time tasks
2006
The size of the response to a startling auditory stimulus (SAS) may reflect the excitability of the reticulospinal tract. In this study, we examined whether there was any excitability change in the reticulospinal tract during preparation for execution of two types of choice reaction time task: a forced choice reaction time task (fCRT) and a Go/no-Go task (GnG). In 13 healthy volunteers we used three types of trials: control trials in which subjects were requested to perform ballistic wrist movements during fCRT or GnG tasks; test trials in which a SAS was presented with the visual cue, and baseline trials in which SAS was presented alone. Latency and area of the responses to SAS were measur…
Learning at the breast: Preference formation for an artificial scent and its attraction against the odor of maternal milk
2006
International audience; Human newborns are known to display spontaneous attraction to the odor of human milk. This study aimed to assess whether the positive response to human milk odor can be explained by nursing-related learning, and whether it can be easily reassigned to a novel odor associated with nursing. Infants were exposed or not to a novel odor (camomile, Ca) during nursing, and tested on day 3–4 for their preference for camomile in comparison with either a scentless control (Exp. 1), a scented control (Exp. 2), or maternal milk (Exp. 3). Prior experience with Ca modified the newborns’ responses. While the Ca odor became more attractive than a scented control in the Ca-exposed gro…
Production of Anti-Endomysial Antibodies in Cultured Duodenal Mucosa: Usefulness in Coeliac Disease Diagnosis
2002
Although anti-endomysial antibodies (EmA) have been found in the supernatants of cultured intestinal mucosa from patients with coeliac disease (CD), in no study has the clinical reliability of this new diagnostic tool been investigated. Our aims were to evaluate the clinical usefulness of the in vitro production of EmA in CD diagnosis in consecutive patients with suspected CD, and to evaluate the reliability of the in vitro challenge in CD patients on a gluten-free diet (GFD).For the former aim, consecutive patients who were due to undergo intestinal biopsy for suspected diagnosis of CD were enrolled: according to the final diagnosis, these patients were divided into two groups: Group 1 com…
Gastrointestinal symptoms in infancy: A population-based prospective study
2005
Abstract Background. During the first months of life, infants can suffer from many ‘minor’ gastroenterological disturbances. However, little is known about the frequency of these problems and the factors which predispose or facilitate their onset. Aims. (a) To ascertain the frequency of the most common gastrointestinal symptoms in infants during the first 6 months after birth; (b) to evaluate the influence of some variables on the onset of the symptoms. Study design and patients. Each of the 150 paediatricians distributed throughout Italy followed 20 consecutive infants from birth to 6 months. 2879 infants (1422 f, 1457 m) concluded the study. The presence of the following symptoms was eval…
Visuospatial processing in schizophrenia: Does it share common mechanisms with pseudoneglect?
2011
International audience; ''Schizophrenia patients demonstrate behavioural and cerebral lateralised anomalies, prompting some authors to suggest they exhibit a mild form of right unilateral neglect. To better describe and understand lateralised visuospatial anomalies in schizophrenia, three experiments were run using tasks often utilised to study visuospatial processing in healthy individuals and in neglect patients: the Behavioural Inattention Test (BIT), the manual line bisection task with and without a local cueing paradigm, the landmark task (or line bisection judgement), and the number bisection task. Although the schizophrenia patients did not exhibit the full-blown neglect syndrome, th…