Fronto-parietal connectivity in the extraction of language rules

Fronto-parietal connectivity in the extraction of language rules

Joan Orpella1,2, and Ruth de Diego-Balaguer1,2,3

1. Department of Cognition, Development and Educational Psychology, Universitat de Barcelona, Spain.

2. Cognition and Brain Plasticity Unit, IDIBELL (Institut d’Investigació Biomèdica de Bellvitge), L'Hospitalet de Llobregat, Spain,

3. ICREA (Catalan Institution for Research and Advanced Studies), Barcelona, Spain

Recent work has placed rule-learning in the centre-stage of research on language acquisition, yet views tend to remain encapsulated within-domain. An integrated account might nevertheless require considering the implication of other cognitive functions. In particular, and because of the temporal aspect in speech processing, the dynamic orienting of attention in time is likely to be crucial in the acquisition of morphosyntactic rules where sequential order is important. Specifically, attentional processes may aid in the selection of relevant information from the speech stream. Given the functional and anatomical overlap between language and attention-in-time fronto-parietal networks, it was hypothesized that the left arcuate fasciculus’ (AF) anterior segment, connecting Broca’s and Geschwind’s territories, may be critical in facilitating implicit rule acquisition. 23 right-handed native Spanish speakers were MRI-scanned so as to delineate the anterior fronto-parietal, posterior parieto-temporal and long fronto-temporal segments of the AF and extract surrogate measures of their axonal properties. Outside the scanner, participants were exposed to an artificial language with sentences containing AxC-type rules while performing a cover word-monitoring task. RTs to word monitoring provided an indirect measure of online incidental rule-learning performance. A subsequent recognition test was then used to gauge participants' recognition of the dependencies.