0000000000459908
AUTHOR
Michel Habib
Pattern detection in ordered graphs
A popular way to define or characterize graph classes is via forbidden subgraphs or forbidden minors. These characterizations play a key role in graph theory, but they rarely lead to efficient algorithms to recognize these classes. In contrast, many essential graph classes can be recognized efficiently thanks to characterizations of the following form: there must exist an ordering of the vertices such that some ordered pattern does not appear, where a pattern is basically an ordered subgraph. These pattern characterizations have been studied for decades, but there have been recent efforts to better understand them systematically. In this paper, we focus on a simple problem at the core of th…
Developmental dyslexia: re-evaluation of the corpus callosum in male adults.
Using a new method based upon the measurement of four angles, we analyzed the corpus callosum of 23 adult male dyslexics and 25 age-matched controls on MRI sagittal scans. Two out of the four angles measured showed significant differences between the groups that are consistent with previous findings concerning the size of the corpus callosum in dyslexics. In particular, posterior regions are concerned, displaying a lowered corpus callosum in dyslexics. These findings are discussed in relation to cortical parietal asymmetries and possible hormonal events, referring to the testosterone hypothesis, that could occur in utero or in the perinatal period in the dyslexic population.
Musique et cerveau : nouveaux concepts, nouvelles applications
International audience; La musique accompagne toute notre vie elle en rythme les étapes, trompe la solitude ou à l'opposé favorise la convivialité et encore en illumine certains moments. Mais elle ne relève pas seulement d'un simple loisir ou d'un moyen d'expression des sentiments. Elle s'enracine profondément dans notre cerveau en coordonnant l'activité de nombreux circuits cérébraux corticaux et sous-corticaux associés à des expériences cognitives, affectives et corporelles. Le pouvoir de la musique sur l'humain fascine aujourd'hui la société. La littérature scientifique s'est enrichie ces dernières décennies de très nombreux travaux précisant les effets de la musique sur le cerveau. L'ob…
Developmental dyslexia: atypical cortical asymmetries and functional significance
Using brain magnetic resonance imaging, we measured in 16 young developmental dyslexic adults and 14 age-matched controls cortical asymmetries of posterior language-related areas, including Planum temporale and parietal operculum cortical ribbon, and of the inferior frontal region related in the left hemisphere to speech processing. In addition, we assessed the sulcal morphology of the inferior frontal gyrus in both groups according to a qualitative method. The dyslexic subjects also performed specific tasks exploring different aspects of phonological and lexical-semantic processes. Results showed that: (1) contrary to most results reported in the literature, there is a lack of any morpholo…
An electrophysiological study of dyslexic and control adults in a sentence reading task.
Event-related potentials and cued-recall performance were used to compare dyslexic and control adult subjects. Sentences that ended either congruously or incongruously were presented visually, one word at a time, at fast (stimulus-onset-asynchrony (SOA)=100 ms) or slow (SOA=700 ms) rates of presentation. Results revealed (1) a large effect of presentation rate that started with the N1-P2 components and lasted for the entire recording period, (2) larger N400 components for dyslexic than control subjects, at slow presentation rates, to both congruous and incongruous endings and (3) a large ERPs difference related to memory (Dm effect) that did not differentiate controls from dyslexics but was…