Neural characteristics of successful and less successful speech and word learning in adults

Abstract

A remarkable characteristic of the human nervous system is its ability to learn to integrate novel (foreign) complex sounds into words. However, the neural changes involved in how adults learn to integrate novel sounds into words and the associated individual differences are largely unknown. Unlike English, most languages of the world use pitch patterns to mark individual word meaning. We report a study assessing the neural correlates of learning to use these pitch patterns in words by English-speaking adults who had no previous exposure to such usage. Before and after training, subjects discriminated pitch patterns of the words they learned while blood oxygenation levels were measured using fMRI. Subjects who mastered the learning program showed increased activation in the left posterior superior temporal region after training, while subjects who plateaued at lower levels showed increased activation in the right superior temporal region and right inferior frontal gyrus, which are associated with nonlinguistic pitch processing, and prefrontal and medial frontal areas, which are associated with increased working memory and attentional efforts. Furthermore, we found brain activation differences even before training between the two subject groups, including the superior temporal region. These results demonstrate an association between range of neural changes and degrees of language learning, specifically implicating the physiologic contribution of the left dorsal auditory cortex in learning success. Hum Brain Mapp 28: [995][996][997][998][999][1000][1001][1002][1003][1004][1005][1006] 2007. V V C 2006 Wiley-Liss, Inc.

Selective neurophysiologic responses to music in instrumentalists with different listening biographies

“…Normalized beta values signifying the fit of the regressors to the functional scanning series, voxel-by-voxel, for each condition were used in multisubject analyses. These analysis procedures are similar to our published studies (e.g., Wong et al, 2007a).…”

“…In total, there were 175 (75 3 2 1 25) 14-s TRs lasting about 41 min. These imaging procedures are similar to our published study (Wong et al, 2007a).…”

“…A sparse sampling method was used, whereby the image acquisition occurred during the first 2 s of the 14-s TR, thus minimizing contamination of the stimuli by scanner noise. In addition, the long TR provided sufficient time for the scanner-noise generated hemodynamic response to decay so that its peak would not overlap with the hemodynamic response generated by the music stimuli [Belin et al, 1999;Gaab and Shlaug, 2003;Hall et al, 1999;Wong et al, 2007a]. There were 75 trials of stimuli for each instrument, order randomized across the fMRI experiment.…”

Functional connectivity between brain regions involved in learning words of a new language

“…For example, Wong, Perrachione, and Parrish (2007) investigated individual differences in the learning of lexical pitch patterns. They found stronger activation in the left posterior superior temporal region for successful learners while less successful learners displayed increased activation in areas involved in nonlinguistic pitch processing, working memory and attention.…”

“…Previous studies on vocabulary acquisition have used standard word-by-word presentation (Breitenstein & Knecht, 2002;Breitenstein et al, 2005;Mei et al, 2008;Wong et al, 2007). However, exposure to an unknown language usually occurs in a complex real world situation where words occur in a continuous speech stream.…”