ABSTRACT
This chapter presents a brief overview of positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) techniques and of their contribution to the field of neurolinguistics. It focuses on the potential role of two variables which may act on language representations of bilinguals: the degree of proficiency in each language and the age of second language acquisition. Functional magnetic resonance imaging is a more recent technique, based on the measurement of magnetic resonance imaging signal changes associated with alterations in local blood oxygenation levels. In general, the functional role of the language-related areas appears to be characterized in terms of linguistically relevant systems, such as phonology, syntax and lexical semantics, rather than in terms of activities, such as speaking, repeating, reading and listening. The areas related to linguistic processing in the normal human brain appear to be not only more extended, but also less fixed than previously thought.
