The goal of this research is to investigate the neural mechanisms which underlie adults'ability to acquire new phonetic categories. Specifically, we will investigate how experience with statistical and referential properties of the input shapes subjects'perceptual sensitivities to items along an acoustic-phonetic continuum, and the neural correlates of these changes in sensitivity. This will be accomplished by using functional MRI (fMRI) to measure activation patterns in adult subjects who have been familiarized with auditory stimuli taken from a non-native phonetic continuum. Importantly, the statistical distribution of the auditory stimuli presented during familiarization, as well as the visual/referential cues which accompany the auditory stimuli will be varied in order to isolate neural correlates of statistical and referential cues to phonetic category identity. Sensitivity of neural structures to equivalent acoustic intervals at different locations along the continuum will be probed using a short-interval habituation paradigm, in which release from adaptation of the fMR signal is used as a marker for neural sensitivity to changes in phonetic category structure. It is argued that changes in activation as a function of familiarization in such areas as the posterior superior temporal gyrus would suggest that the changes in phonetic category structure are mediated early in the phonetic processing stream. Alternatively, changes in activation in the frontal (inferior frontal gyrus) and parietal (supramarginal gyrus, angular gyrus) structures would suggest that the warping of phonetic categories occurs later in the processing stream and reflects the recruitment of attentional, lexical, or executive systems. Results will shed light on the process by which statistical and referential cues shape perceptual sensitivities which ultimately form the basis of phonetic categories. Relevance: The proposed research will shed light on the neural mechanisms which underlie the acquisition of phonetic categories, and may ultimately be used to inform treatment strategies for children with developmental language disorders. Additionally, results should add to our understanding of the neural bases of speech processing in adults, which may be used to suggest rehabilitative strategies for aphasic patients who have suffered language impairments due brain injury.

Public Health Relevance

Relevance The proposed research will shed light on the neural mechanisms which underlie the acquisition of phonetic categories, and may ultimately be used to inform treatment strategies for children with developmental language disorders. Additionally, results should add to our understanding of the neural bases of speech processing in adults, which may be used to suggest rehabilitative strategies for aphasic patients who have suffered language impairments due brain injury.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Small Research Grants (R03)
Project #
5R03DC009495-03
Application #
7991834
Study Section
Special Emphasis Panel (ZDC1-SRB-R (34))
Program Officer
Shekim, Lana O
Project Start
2008-12-05
Project End
2013-11-30
Budget Start
2010-12-01
Budget End
2013-11-30
Support Year
3
Fiscal Year
2011
Total Cost
$155,248
Indirect Cost
Name
Brown University
Department
Miscellaneous
Type
Schools of Arts and Sciences
DUNS #
001785542
City
Providence
State
RI
Country
United States
Zip Code
02912
Myers, Emily B; Theodore, Rachel M (2016) Voice-sensitive brain networks encode talker-specific phonetic detail. Brain Lang 165:33-44
Earle, F Sayako; Myers, Emily B (2015) Overnight consolidation promotes generalization across talkers in the identification of nonnative speech sounds. J Acoust Soc Am 137:EL91-7
Xie, Xin; Myers, Emily (2015) The impact of musical training and tone language experience on talker identification. J Acoust Soc Am 137:419-32
Earle, F Sayako; Myers, Emily B (2015) Sleep and native language interference affect non-native speech sound learning. J Exp Psychol Hum Percept Perform 41:1680-95
Myers, Emily B (2014) Emergence of category-level sensitivities in non-native speech sound learning. Front Neurosci 8:238
Myers, Emily B; Mesite, Laura M (2014) Neural Systems Underlying Perceptual Adjustment to Non-Standard Speech Tokens. J Mem Lang 76:80-93
Swan, Kristen; Myers, Emily (2013) Category labels induce boundary-dependent perceptual warping in learned speech categories. Second Lang Res 29:391-411
Myers, Emily B; Swan, Kristen (2012) Effects of category learning on neural sensitivity to non-native phonetic categories. J Cogn Neurosci 24:1695-708