The goal of this research is to understand how the functional architecture of the speech-lexical processing system maps on to the neural systems underlying it using event-related functional magnetic resonance imaging (fMRI). Two hypotheses will be investigated, both exploring the neural systems underlying the computational properties of auditory speech and lexical processing. The first hypothesis explores whether the computational mechanisms of the two hemispheres preferentially process different properties of the speech signal. A series of experiments using both speech discrimination and phonetic categorization tasks will examine a number of acoustic-phonetic parameters underlying both consonant and vowel perception including voice-onset time and formant frequency duration in the perception of consonants, and duration and formant frequency (F l-F2) space in the perception of vowels. It is hypothesized that the acoustic properties corresponding to the phonetic categories of speech will be preferentially processed by the left hemisphere irrespective of their acoustic structure owing to the functional role that sound structure plays in language processing. In contrast, it is hypothesized that activation of the right hemisphere will be modulated by the inherent acoustic properties of the speech signal. The second hypothesis explores how the computational properties of the speech lexical processing system map on to its neural substrate. It is hypothesized that there will be increased left frontal activation under conditions of phonetic-phonological, lexical, and/or semantic competition. Phonetic competition will be investigated by exploring the extent to which acoustic-phonetic structure and the proximity of an exemplar to a contrasting, and hence, competing phonetic category influences frontal activation. Lexical competition will be investigated by exploring the influence of phonetic factors on lexical competition and phonological factors on lexical neighborhood density. Semantic competition will be investigated by exploring the effects of semantically ambiguous words compared to unambiguous words on neural activation patterns.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC006220-02
Application #
6898833
Study Section
Language and Communication Study Section (LCOM)
Program Officer
Cooper, Judith
Project Start
2004-06-01
Project End
2009-04-30
Budget Start
2005-05-01
Budget End
2006-04-30
Support Year
2
Fiscal Year
2005
Total Cost
$348,354
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
Reilly, Megan; Blumstein, Sheila E (2014) Effect of sound similarity and word position on lexical selection. Lang Cogn Neurosci 29:1325-1341
Guediche, Sara; Salvata, Caden; Blumstein, Sheila E (2013) Temporal cortex reflects effects of sentence context on phonetic processing. J Cogn Neurosci 25:706-18
Minicucci, Domenic; Guediche, Sara; Blumstein, Sheila E (2013) An fMRI examination of the effects of acoustic-phonetic and lexical competition on access to the lexical-semantic network. Neuropsychologia 51:1980-8
Peramunage, Dasun; Blumstein, Sheila E; Myers, Emily B et al. (2011) Phonological neighborhood effects in spoken word production: an fMRI study. J Cogn Neurosci 23:593-603
Righi, Giulia; Blumstein, Sheila E; Mertus, John et al. (2010) Neural systems underlying lexical competition: an eye tracking and fMRI study. J Cogn Neurosci 22:213-24
Bilenko, Natalia Y; Grindrod, Christopher M; Myers, Emily B et al. (2009) Neural correlates of semantic competition during processing of ambiguous words. J Cogn Neurosci 21:960-75
Britton, Brendan; Blumstein, Sheila E; Myers, Emily B et al. (2009) The role of spectral and durational properties on hemispheric asymmetries in vowel perception. Neuropsychologia 47:1096-106
Wallace, Andrew B; Blumstein, Sheila E (2009) Temporal integration in vowel perception. J Acoust Soc Am 125:1704-11
Myers, Emily B; Blumstein, Sheila E; Walsh, Edward et al. (2009) Inferior frontal regions underlie the perception of phonetic category invariance. Psychol Sci 20:895-903
Blumstein, Sheila E (2009) Auditory word recognition: evidence from aphasia and functional neuroimaging. Lang Linguist Compass 3:824-838

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