Summary

Language-related areas within left frontal, parietal and temporal cortices are organized in dorsal and ventral segregated but highly interactive streams. Studying individual differences in functional and structural connectivity between those brain regions and how they change during language learning can clarify the function of each of these specific connections in learning dysfunction and inter-individual variability. While the dorsal stream has been related to articulation and production, the ventral stream has been associated with comprehension and semantic processing. To understand their role in the earliest stages of language learning, we have used artificial languages to study the acquisition of word forms from fluent speech without the influence of semantic information. The evidence commented on here indicates that the direct functional and structural connectivity between left frontal and temporal structures is relevant for audio-motor integration and critical for the acquisition of new word forms. Indeed, interference with this audio-motor component required for working memory maintenance of the phonological form disrupts language learning. Within the dorsal network as well, other studies highlight the importance of attention orienting associated with the left fronto-parietal network in the extraction of the embedded rules of words. Regarding the ventral network, the data indicate the relevance of the ventral connection between left frontal and temporal areas as a supporting pathway in the early acquisition process even when no semantic information is available.