Auditory Working Memory Training Leads to Specific Decreases in Left Prefrontal Cortex When Learning The Phonology Of Chinese Words

Logographic Chinese differs from alphabetic languages in aspects of orthography and phonology. While there are different neural networks involved in processing orthography across these language systems, there is evidence for a common neural network across languages for auditory phonology. Since lexical tones are phonemically relevant in Chinese only, learning Chinese phonology should benefit more from auditory than visual working memory (WM) training and result in activation decreases in its underlying neural circuitry. We used an n-back WM training procedure to investigate the differential impact of auditory and visual WM training on phonological proficiency while Germans learned the phonology of Chinese words. Training-inducedmodulations in language-related networkswere examined bymeans offMRI. Behavioral data did not show any transfer from auditory and visual WM training to phonological proficiency compared to a control group. Brain imaging analyses during pretest revealed activations in the left medial frontal gyrus, anterior cingulate gyrus and pallidum. Importantly, volume-of-interest analyses in these regions showed training-induced activation decreases in the medial frontal gyrus for the auditory training group but not for the other two groups. These results suggest that the training of auditoryWMleads - even in the absence of behavioral transfer effects - to more efficient processing within the left dorsal prefrontal cortex when learning Chinese phonology probably reflecting facilitated attentional selection of phonetic information in spoken Chinese words