Language is specific to the human and can, thus, not be studied in the animal. In the adult, there is a strong dominance of the left hemisphere for most aspects of language and stroke in language regions often leads to permanent aphasia. In contrast, lesions in similar locations acquired very early do not lead to an impaired language function in the affected child.
With the advent of fMRI, the cerebral representation of language organisation can now be studied non-invasively even in smaller children.
Questions 1. Language representation during development?
2. Early left hemispheric lesions and language representation?
3. If there is language reorganisation, does it affect right hemispheric functions?
4. How good is right hemispheric language?
5. What is the time frame for reorganisation?
Language representation is initially bilateral and increasingly left dominated during development.
Early left hemispheric lesions may induce reorganisation to the right – in homotopic areas.
This happens on the expense of right hemispheric functions.
Language quality in reorganised language is not impaied for everyday language, but there are differences in complex linguistic aspects, which supports the idea of a genetic predisposition.
The time frame for reorganisation is not very clear, but there is no evidence for successful reorganisation after preschool age.
AnswersThis work is supported by the German Research Council (DFG) and the University of Tübingen.