48 research outputs found
Differences in Brain Function and Changes with Intervention in Children with Poor Spelling and Reading Abilities
Previous fMRI studies in English-speaking samples suggested that specific interventions may alter brain function in language-relevant networks in children with reading and spelling difficulties, but this research strongly focused on reading impaired individuals. Only few studies so far investigated characteristics of brain activation associated with poor spelling ability and whether a specific spelling intervention may also be associated with distinct changes in brain activity patterns. We here investigated such effects of a morpheme-based spelling intervention on brain function in 20 children with comparatively poor spelling and reading abilities using repeated fMRI. Relative to 10 matched controls, children with comparatively poor spelling and reading abilities showed increased activation in frontal medial and right hemispheric regions and decreased activation in left occipito-temporal regions prior to the intervention, during processing of a lexical decision task. After five weeks of intervention, spelling and reading comprehension significantly improved in the training group, along with increased activation in the left temporal, parahippocampal and hippocampal regions. Conversely, the waiting group showed increases in right posterior regions. Our findings could indicate an increased left temporal activation associated with the recollection of the new learnt morpheme-based strategy related to successful training
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
The effect of experimental disturbances
on the dynamics of a shrub community was studied
on a ‘Montado’ ecosystem, in southern Portugal. The
evolution of the community physiognomy, composition
and diversity were monitored after shrub clearing
followed by biomass removal, deposition on soil
surface and incorporation with the soil, over a 9-year
period. Maximum shrub density was recorded in the
first year after the disturbances, excepting in mulched
plots which showed the greatest number of individuals
1 year later. The increment of shrub leaf biomass
was very fast in the first 3 years, whereas wood
production was slower but occurred along the whole
study period. At the end of the study, leaf and wood
biomass was still significantly lower than in the predisturbance
situation. The variation pattern of leaf
area index was similar to that of leaf biomass. The
evolution of total plant cover and diversity was
similar across treatments. The highest species richness
and diversity were recorded 2 years after
cutting, decreasing afterwards with the increasing
dominance of shrubs. Thus it seems likely that,
although a 9 year period is too short for these
communities to reach steady equilibrium, they are
very resistant and resilient to disturbances, as regeneration
was fast and vegetation dynamics was not
influenced by differences among treatments. We can
conclude that shrub clearing promotes biodiversity
and the time of permanence of shrub patches depends
on the particular goal we want to achieve
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
The effect of experimental disturbances
on the dynamics of a shrub community was studied
on a ‘Montado’ ecosystem, in southern Portugal. The
evolution of the community physiognomy, composition
and diversity were monitored after shrub clearing
followed by biomass removal, deposition on soil
surface and incorporation with the soil, over a 9-year
period. Maximum shrub density was recorded in the
first year after the disturbances, excepting in mulched
plots which showed the greatest number of individuals
1 year later. The increment of shrub leaf biomass
was very fast in the first 3 years, whereas wood
production was slower but occurred along the whole
study period. At the end of the study, leaf and wood
biomass was still significantly lower than in the predisturbance
situation. The variation pattern of leaf
area index was similar to that of leaf biomass. The
evolution of total plant cover and diversity was
similar across treatments. The highest species richness
and diversity were recorded 2 years after
cutting, decreasing afterwards with the increasing
dominance of shrubs. Thus it seems likely that,
although a 9 year period is too short for these
communities to reach steady equilibrium, they are
very resistant and resilient to disturbances, as regeneration
was fast and vegetation dynamics was not
influenced by differences among treatments. We can
conclude that shrub clearing promotes biodiversity
and the time of permanence of shrub patches depends
on the particular goal we want to achieve
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
Developmental dyscalculia: a dysconnection syndrome?
Numerical understanding is important for everyday life. For children with developmental dyscalculia (DD), numbers and magnitudes present profound problems which are thought to be based upon neuronal impairments of key regions for numerical understanding. The aim of the present study was to investigate possible differences in white matter fibre integrity between children with DD and controls using diffusion tensor imaging. White matter integrity and behavioural measures were evaluated in 15 children with developmental dyscalculia aged around 10Â years and 15 matched controls. The main finding, obtained by a whole brain group comparison, revealed reduced fractional anisotropy in the superior longitudinal fasciculus in children with developmental dyscalculia. In addition, a region of interest analysis exhibited prominent deficits in fibres of the superior longitudinal fasciculus adjacent to the intraparietal sulcus, which is thought to be the core region for number processing. To conclude, our results outline deficient fibre projection between parietal, temporal and frontal regions in children with developmental dyscalculia, and therefore raise the question of whether dyscalculia can be seen as a dysconnection syndrome. Since the superior longitudinal fasciculus is involved in the integration and control of distributed brain processes, the present results highlight the importance of considering broader domain-general mechanisms in the diagnosis and therapy of dyscalculia