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C Pallier

Publications and source records attributed to C Pallier.

18 recordsLinked to original sources
PubMed2005

Modulation of language areas with functional MR image-guided magnetic stimulation.

Repetitive transcranial magnetic stimulation (rTMS) can interfere with linguistic performance when delivered over language areas. At low frequency (1 Hz), rTMS is assumed to decrease cortical excitability; however, the degree of TMS effect on cortical language areas may depend on the localization of the stimulation coil with respect to the inter-individual anatomo-functional variations. Hence, we aimed at investigating individual brain areas involved in semantic and phonological auditory processes. We hypothesized that active rTMS targeted over Wernicke's area might modify the performance during a language-fragment-detection task. Sentences in native or foreign languages were presented to 12 right-handed male healthy volunteers during functional magnetic resonance imaging (fMRI). 3D-functional maps localized the posterior temporal activation (Wernicke) in each subject and MRI anatomical cortical landmarks were used to define Broca's pars opercularis (F3Op). A frameless stereotaxy system was used to guide the TMS coil position over Wernicke's and F3Op areas in each subject. Active and placebo randomized rTMS sessions were applied at 1 Hz, 110% of motor threshold, during the same language-fragment-detection task. Accuracy and response time (RT) were recorded. RT was significantly decreased by active rTMS compared to placebo over Wernicke's area, and was more decreased for native than for foreign languages. No significant RT change was observed for F3Op area. rTMS conditions did not impair participants' accuracy. Thus, low-frequency rTMS over Wernicke's area can speed-up the response to a task tapping on native language perception in healthy volunteers. This individually-guided stimulation study confirms that facilitatory effects are not confined to high-frequency rTMS.

Adult↗
PubMed2005

Reversibility of the other-race effect in face recognition during childhood.

Early experience with faces of a given racial type facilitates visual recognition for this type of face relative to others. To assess whether this so-called other-race effect can be reversed by subsequent experience with new types of faces, we tested adults of Korean origin who were adopted by European Caucasian families when they were between the ages of 3 to 9. The adoptees performed a face recognition task with photographs of Caucasian and Asian faces. They performed exactly like a control group of French participants, identifying the Caucasian faces better than the Asiatic ones. In contrast, a control group of Koreans showed the reverse pattern. This result indicates that the face recognition system remains plastic enough during childhood to reverse the other-race effect.

Adult↗
PubMed2004

[Viral transmission and medically assisted procreation: the Herpesviridae case].

Procreation with sperm donation is at present achieved by insemination either in the uterus or in vitro, always from ejaculated and washed spermatozoa. Then, the infectious risk only exists if the donor sperm is capable of transporting the virus or its DNA, either by adhesion or by integration. With CMV, HSV1 and HSV2, medically assisted procreation in couples (AI or IVF-ET) does not increase the risk of viral contamination as compared with natural procreation, except possibly the cases of surgical procedure to pick up testicular sperm to be used in ICSI. Animal experiments show that, even if viral material is introduced in the oocyte, it may be eliminated from the embryo, at least for CMV.

Female↗
PubMed2003

Brain imaging of language plasticity in adopted adults: can a second language replace the first?

Do the neural circuits that subserve language acquisition lose plasticity as they become tuned to the maternal language? We tested adult subjects born in Korea and adopted by French families in childhood; they have become fluent in their second language and report no conscious recollection of their native language. In behavioral tests assessing their memory for Korean, we found that they do not perform better than a control group of native French subjects who have never been exposed to Korean. We also used event-related functional magnetic resonance imaging to monitor cortical activations while the Korean adoptees and native French listened to sentences spoken in Korean, French and other, unknown, foreign languages. The adopted subjects did not show any specific activations to Korean stimuli relative to unknown languages. The areas activated more by French stimuli than by foreign stimuli were similar in the Korean adoptees and in the French native subjects, but with relatively larger extents of activation in the latter group. We discuss these data in light of the critical period hypothesis for language acquisition.

Adoption↗
PubMed2001

The influence of native-language phonology on lexical access: exemplar-Based versus abstract lexical entries.

This study used medium-term auditory repetition priming to investigate word-recognition processes. Highly fluent Catalan-Spanish bilinguals whose first language was either Catalan or Spanish were tested in a lexical decision task involving Catalan words and nonwords. Spanish-dominant individuals, but not Catalan-dominant individuals, exhibited repetition priming for minimal pairs differing in only one feature that is nondistinctive in Spanish (e.g.,[see text]), thereby indicating that they processed these words as homophones. This finding provides direct evidence both that word recognition uses a language-specific phonological representation and that lexical entries are stored in the mental lexicon as abstract forms.

Adult↗
PubMed1998

Perceptual adjustment to time-compressed speech: a cross-linguistic study.

Previous research has shown that, when hearers listen to artificially speeded speech, their performance improves over the course of 10-15 sentences, as if their perceptual system was "adapting" to these fast rates of speech. In this paper, we further investigate the mechanisms that are responsible for such effects. In Experiment 1, we report that, for bilingual speakers of Catalan and Spanish, exposure to compressed sentences in either language improves performance on sentences in the other language. Experiment 2 reports that Catalan/Spanish transfer of performance occurs even in monolingual speakers of Spanish who do not understand Catalan. In Experiment 3, we study another pair of languages--namely, English and French--and report no transfer of adaptation between these two languages for English-French bilinguals. Experiment 4, with monolingual English speakers, assesses transfer of adaptation from French, Dutch, and English toward English. Here we find that there is no adaptation from French and intermediate adaptation from Dutch. We discuss the locus of the adaptation to compressed speech and relate our findings to other cross-linguistic studies in speech perception.

Adult↗
PubMed1997

A limit on behavioral plasticity in speech perception.

It is well attested that we perceive speech through the filter of our native language: a classic example is that of Japanese listeners who cannot discriminate between the American /l/ and /r/ and identify both as their own /r/ phoneme (Goto. H., 1971. Neuropsychologia 9, 317-323.). Studies in the laboratory have shown, however, that perception of non-native speech sounds can be learned through training (Lively, S.E., Pisoni, D.B., Yamada, R.A., Tohkura, Y.I., Yamada, T., 1994. Journal of the Acoustical Society of America 96 (4), 2076-2087). This is consistent with neurophysiological evidence showing considerable experience-dependent plasticity in the brain at the first levels of sensory processing (Edeline, J.-M., Weinberger, N.M., 1993. Behavioral Neuroscience 107, 82-103; Merzenich, M.M., Sameshima, K., 1993. Current Opinion in Neurobiology 3, 187-196; Weinberger, N.M., 1993. Current Opinion in Neurobiology 3, 577-579; Kraus, N., McGee, T., Carrel, T.D., King, C., Tremblay, K., Nicol, T., 1995. Journal of Cognitive Neuroscience 7 (1), 25-32). Outside of the laboratory, however, the situation seems to differ: we here report is study involving Spanish-Catalan bilingual subjects who have had the best opportunities to learn a new contrast but did not do it. Our study demonstrates a striking lack of behavioral plasticity: early and extensive exposure to a second language is not sufficient to attain the ultimate phonological competence of native speakers.

Analysis of Variance↗
PubMed1997

Establishment of a cell line expressing human parvovirus B19 non-structural protein from an inducible promoter.

Human parvovirus B19 non-structural (NS) protein is supposed to play a major role in B19 replication and transcription, and therefore in B19 pathogenicity. Constitutive expression of NS protein in stable cell lines has failed so far, presumably because of its cytotoxicity. To avoid this cytotoxic effect, we have cloned the NS gene in an Epstein-Barr virus episomal vector under the control of a steroid inducible promoter (5xGRE) and transfected this construction into HeLa cells. We obtained stable cell lines inducibly expressing high level of NS protein, with 50% of the cells demonstrating specific nucleo-cytoplasmic staining. In Western blot analysis, three B19 NS proteins (72, 68 and 60 kDa) were found but a unique NS transcript was detected by Northern blotting. The NS protein expressed in HeLa cell lines was demonstrated to be functional as it trans-activates the B19 P6 promoter. These cell lines might be major tools for further study and characterization of B19 NS protein.

Blotting, Western↗
PubMed1997

The 3' untranslated region of the B19 parvovirus capsid protein mRNAs inhibits its own mRNA translation in nonpermissive cells.

Although parvoviruses are found throughout the animal kingdom, only the human pathogenic B19 virus has so far been shown to possess a limited host range, with erythroid progenitor cells as the main target cells supporting B19 propagation. The underlying mechanism of such erythroid tropism is still unexplained. Synthesis of the NS1 nonstructural protein occurs in permissive and nonpermissive cells, such as megakaryocytes, whereas synthesis of the VP1 and VP2 capsid proteins seems to be restricted to burst-forming units and CFU of erythroid cells. In nonpermissive cells, the NS1 protein is overexpressed and the NS1 RNAs are the predominant RNA species. However, the VP1 and VP2 proteins are not detectable, although the corresponding mRNAs are synthesized. Since all transcripts have part of the 5' untranslated region (5' UTR) in common but distinct 3' UTRs characterizing the nonstructural- and structural-protein mRNAs, we investigated, in transient transfection assays, the possible involvement of the 3' UTR of the capsid protein mRNAs in VP1 and VP2 protein synthesis in nonpermissive Cos cells. The results showed that (i) the 3' UTR of mRNAs coding for the capsid proteins repressed VP1 and VP2 protein synthesis, (ii) the 3' UTR did not affect nuclear export or mRNA stability, and (iii) mRNAs bearing the 3' UTR of the capsid protein mRNAs did not associate with ribosomes at all. Taken together, these results indicate that in nonpermissive cells, the 3' UTR of the capsid protein mRNAs represses capsid protein synthesis at the translational level by inhibiting ribosome loading.

Animals↗
PubMed1996

Antibody response to human parvovirus B19 in patients with primary infection by immunoblot assay with recombinant proteins.

Human parvovirus B19 recombinant VP1 and VP2 capsid proteins were produced by a procaryotic pGEX expression plasmid to evaluate the humoral response by immunoblot assay in 14 patients with primary infection. The same concentrations of VP1 and VP2 recombinant proteins were used. This demonstrates that VP1 immunoglobulin M detection and/or VP1 immunoglobulin G seroconversion is a reliable marker of primary infections. Consequently, detection of antibodies to B19 VP1 might be helpful for identifying patients at risk for chronic B19 infection or patients who are susceptible to viral reinfection.

Adolescent↗
PubMed1994

Complete DNA sequence of yeast chromosome XI.

The complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome XI has been determined. In addition to a compact arrangement of potential protein coding sequences, the 666,448-base-pair sequence has revealed general chromosome patterns; in particular, alternating regional variations in average base composition correlate with variations in local gene density along the chromosome. Significant discrepancies with the previously published genetic map demonstrate the need for using independent physical mapping criteria.

Base Sequence↗
PubMed1994

Cross-linguistic approaches to speech processing.

Recent advances in the field of speech processing indicate that speakers of differing languages process speech relying on units that are appropriate to the rhythmical properties of their maternal tongue. Studies with young infants suggest that the acquisition of these processing routines takes place before the end of the first year of life. Further evidence shows that the left hemisphere initially processes any language and gradually becomes specialized for the maternal language.

Adult↗
PubMed1994

Differential transcription, without replication, of non-structural and structural genes of human parvovirus B19 in the UT7/EPO cell as demonstrated by in situ hybridization.

Erythroid progenitor cells are the main target for B19 parvovirus infection. The UT7 cell line demonstrates a marked erythroid differentiation on induction by erythropoietin (EPO) (UT7/EPO cells) and therefore appears to be a potential target for B19 parvovirus. We aimed to evaluate the presence and localization of B19 nucleic acids in UT7/EPO cells by in situ hybridization. Three digoxigenin-labelled probes were used: two recognized specifically the non-structural region of the B19 genome and one probe was structural region-specific. In our experiment UT7/EPO cells were not permissive to B19 infection. Transcription led to nonstructural and structural gene transcripts without DNA replication or capsid protein synthesis.

Base Sequence↗
PubMed1993

DNA sequence analysis of a 17 kb fragment of yeast chromosome XI physically localizes the MRB1 gene and reveals eight new open reading frames, including a homologue of the KIN1/KIN2 and SNF1 protein kinases.

We report in this paper the sequence of a part of chromosome XI of Saccharomyces cerevisiae. This 17 kbp nucleotide sequence represents the right half of cosmid pUKG151 and contains nine open reading frames, YKL453, 450, 449, 448, 445, 443, 442, 441 and the 5' part of YKL440. YKL440 was previously identified as the MBR1 gene and plays a role in mitochondrial biogenesis. YKL443 is a homologue of the yeast serine-rich protein (SRP1), while YKL453 presents strong homologies with the KIN1/KIN2/SNF1 kinase family. It must be pointed out that the size of this gene is well above average for yeast.

Amino Acid Sequence↗
PubMed1993

The DNA sequence analysis of the HAP4-LAP4 region on chromosome XI of Saccharomyces cerevisiae suggests the presence of a second aspartate aminotransferase gene in yeast.

The nucleotide sequence of a 19,000 base pair region from the left arm of chromosome XI of Saccharomyces cerevisiae has been determined and analysed. It covers the HAP4-GFA1-LAP4 loci already described. As expected HAP4, GFA1 and LAP4 genes have been found and six new open reading frames (ORFs) with a coding capacity of more than 100 amino acid residues have been identified. One of them (YKL461) shows a high degree of identity with an aspartate aminotransferase gene. This raises the question of a second aspartate aminotransferase gene in yeast. A second ORF (YKL462) shows features compatible with a membranous localization. The other ORFs do not show a similarity with any known gene. A member of the highly repetitive 'CAT' DNA sequence is present.

Aspartate Aminotransferases↗
PubMed1991

Mutational studies of the major tRNA region of the S. cerevisiae mitochondrial genome.

The major tRNA genes in S. cerevisiae mitochondria are contained within a 20 kb segment of the mitochondrial DNA. In order to analyze the functional role of this region we have isolated several mitochondrial mutations, which are temperature-sensitive for growth on non-fermentable carbon sources. These mutations, localized in the major tRNA cluster region, can be classified in different groups according to their (a) genetic and physical localization, (b) spectrum of suppression and (c) biochemical characteristics. Some of these are mutations in tRNA genes which affect tRNA function; others alter the synthesis of the gene product. Finally, we found two mutations localized in, or in the vicinity of, the open reading frame RF2. RF2 has been postulated to be a maturase-like protein (Michel 1984) but no function for it has yet been demonstrated. The existence of defective mutants may confirm that RF2 is indeed necessary for mitochondrial biogenesis and so allow for a study of the expression of this gene.

Chromosome Mapping↗