Neural correlates associated with learning adjacent and non-adjacent regularities during statistical learning: An fMRI study.

Eghbalzad, L. , Deocampo, J. , Smith, G. , Na, S. , King, T. & Conway, C.

Georgia State University

The ability to learn sequential dependencies is essential for language acquisition. Recent studies suggest there may be separate cognitive processes involved in learning adjacent versus non-adjacent dependencies, but the neural correlates accompanying such learning are under-specified. We developed a visuo-syllabic sequential learning task, in which sequences of printed nonsense syllables generated from an artificial grammar dictating adjacent and non-adjacent dependencies were presented. After learning these grammatical sequences, sixteen healthy adults (age M=22.5, 9 females) made familiarity judgments about novel grammatical and ungrammatical sequences containing violations of the adjacent or non-adjacent dependencies while in a 3T MRI scanner. We evaluated BOLD activity using fMRI. The imaging analyses revealed bilateral activation of middle frontal gyrus (BAs 9 & 10) and left lateralized activation of precuneus and lingual gyrus (BAs 7 & 18) for the ungrammatical compared to grammatical sequences. Furthermore, increased activation in BA 7 and 18 correlated with participants? learning of adjacent dependencies (p<0.05) whereas activation in BAs 9 &10 correlated with digit span backward and processing speed (p<0.05). Results suggest that learning structured sequences involves posterior perceptual regions, associated with adjacent-item pattern learning, and frontal regions, associated with working memory and learning non-adjacent dependencies.