[Brain plasticity for language in children and adolescents]

Plasticity makes possible adaptative modelling of the nervous system to experiences i.e. learning and development.

To review current literature on clinical long term evolution and functional magnetic resonance imaging (fMRI) features of brain remodelling after focal stroke in left perisylvian regions involved in basic language processing during infancy and childhood.

Each of the main neurocognitive subsystems develops with different timing, so altered plasticity and vulnerability are diverse, according with age at insult and its topography. Genetic programming makes human brain capable for installing basic formal linguistic abilities on an associative perisylvian subsystem, highly specialised. A focal lesion of this region leads to remodelling phenomena by disinhibition of contralateral frontal and perisylvian structures and by a more or less efficacious activation of neighboring homolateral cortex, as it has been shown by fMRI studies and DTI tractography. As a result, very early local stroke to language areas is generally well compensated in terms of linguistic behaviour. Meanwhile acquired aphasias into middle and late childhood, even if they have a better prognosis than in adults, they fail to resume without lexical access defaults and/or difficulties in written language.

Brain plasticity can promote restoration and further development of language following a stroke in left peri-sylvian areas, specially when lesion occurs at perinatal to middle childhood.