Central nervous system markers for lexical tone learning
Patrick C. M. Wong · The Journal of the Acoustical Society of America · 2012
A large degree of individual variability can be observed in language learning in adulthood. This variability is especially prominent in the learning of foreign sounds, including lexical tones. In this presentation, I will report a series of experiments from my research group that examines the central nervous system markers for lexical tone learning success. Our knowledge such as collicular sensitivity to frequency modulation and cortical basis of pitch perception can begin to assist in generating specific hypotheses for these markers. In our experiments, native English-speaking adults learned Mandarin-like tone patterns in a lexical context. Behavioral, electrophysiological, neural hemodynamic (fMRI), and neuroanatomical measures were collected to characterize variability in learning success. Among the markers of success we found were integrity of the frequency following response, activity in the posterior auditory cortex, gray matter volume in the Heschl's Gyrus, and white matter connectivity within the auditory cortex. Some of these markers were used to redesign training in order to optimize learning for all learners, including training strategies such as enhancing auditory pitch cues and reducing trial-by-trial stimulus variability. Taken together, these experiments provide information regarding the neural basis of lexical tone learning and demonstrate the feasibility of using biomarkers for designing training. [Work supported by NIH and NSF]