Electrophysiology of language (speech) production

Purpose: Language (speech) production involves semantic, syntactic and phonological information that has be retrieved for the word to be produced. The studies reviewed in this paper concern the temporal order in which each information becomes available. Method: Event-related brain potentials were recorded in young healthy subjects in an implicit picture naming task. In every experiment two types of information (e.g. semantic information and phonology) were tested against each other. The N200 NoGo component served as a time marker for the availability of the studied type of information. Results: The following time course was found during picture naming: semantic information preceded syntax, while syntax preceded phonology. By contrast, two parallel experiments on auditory word comprehension showed the following pattern: phonology earlier than semantic information, whereas semantics preceded syntax. Discussion: Event-related brain potentials permit a temporally precise delineation of information availability in language/peech production tasks. These findings can be used to test predictions of language/speech processing models.