- UNDERGRADUATE PROGRAMS
- GRADUATE PROGRAMS
Albert D. Mead Professor
Speech and lexical processing, cognitive neuroscience of language
Sheila E. Blumstein is the Albert D. Mead Professor of Cognitive, Linguistic and Psychological Sciences at Brown University. Blumstein has been at Brown since 1970. She is a 1965 magna cum laude graduate in linguistics of the University of Rochester and she earned her Ph.D. in linguistics at Harvard University in 1970. She came to Brown as an assistant professor in linguistics in 1970, was promoted to associate professor in 1976, and became a full professor in 1981. She was chairman of the Department of Linguistics from 1978-81, Chairman of the Department of Cognitive and Linguistic Sciences from 1986-87, in 1997, and from 1998 to 2000, and Associate Chair from 2008-2010. She has served as Dean of the College at Brown from 1987-1995, as Interim Provost in 1998, and as Interim President from February 2000 to July 2001. Blumstein has published extensively on the neural basis of speech and language processing using both lesion-based and functional neuroimaging methods. She has served as member of a number of scientific review panels and boards for the National Institutes of Health, the National Science Foundation, and the McDonnell Pew Program in Cognitive Neuroscience. She has been the recipient of a number of honors and awards including a Guggenheim Fellowship, a Claude Pepper Award from the National Institutes of Health, a Radcliffe Institute Fellowship, and an Honorary Doctorate as well as the Susan Colver Rosenberger Medal, both from Brown University. She has been elected fellow of the Acoustical Society of America, the American Academy of Arts and Sciences, the American Philosophical Society, the American Association for the Advancement of Science, and the Linguistic Society of America.
My research is concerned with the biology and neurology of language and the processes involved in speaking and understanding. The research methodologies used in my lab include behavioral measures of aphasic patients correlated with structural measures of neuropathology and neural modeling and functional neuroimaging of normal subjects.
RESEARCH IN APHASIA
My research in aphasia explores the effects of brain damage on normal language processing as a window into the neurological bases of language and the mechanisms contributing to normal language processing. The major focus of this research is on sound structure and the lexicon and the processing stages that map sound to meaning and meaning to sound. In particular, we are examining the effects of acoustic-phonetic, lexical, phonological, and semantic competition on the lexical processing of aphasic patients and investigating how higher level stages of lexical processing interact with and influence processing stages downstream from it.
In investigating the mapping from sound to meaning, it is hypothesized that deficits should emerge for patients with lesions involving the inferior frontal gyrus (IFG) under conditions of lexical and lexical-semantic competition, whereas deficits should emerge for patients with lesions including the supramarginal gyrus when competition is induced by phonological lexical density. Higher-level stages of processing from lexical semantics or sentence context should override processing deficits that emerge under conditions of lexical competition.
In the investigations of the mapping from sound to meaning, we are exploring whether acoustic traces of the original target will emerge in the production of phonemic paraphasias. We are also exploring the extent to which neighborhood density influences the articulatory implementation of lexical targets.This influence should be overcome by the effects of higher-level lexical-semantic information.
RESEARCH ON THE NEURAL SYSTEMS UNDERLYING SPEECH AND LEXICAL PROCESSING USING fMRI
The goals of this research are to understand the neural systems underlying the computational properties of speech perception and how the computational properties of the speech-lexical processing system map on to its neural substrate.
Although there is general consensus that the functional role of anterior and posterior areas differ in the perception of speech — with posterior areas, e.g. transverse temporal gyrus and superior temporal gyrus, involved in the sensory processing of the stimuli and anterior areas, e.g. inferior frontal gryus, involved in executive processes — there is less consensus about the functional role of the two hemispheres. We intend to investigate whether the computational mechanisms of the two hemispheres preferentially process different properties of the speech signal. Our hypothesis is that the acoustic properties 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. Nonetheless, despite this left hemisphere preference, we hypothesize modulation of right hemisphere mechanisms as a function of the acoustic structure of the stimuli, with increased right hemisphere activation for acoustic properties that require fine spectral analysis and have a longer inherent duration.
A series of experiments using both speech discrimination and phonetic categorization tasks are planned to examine activation patterns in the processing of a number of acoustic-phonetic parameters underlying both consonant and vowel perception.
In addition, we plan to investigate the computational properties of the speech-lexical processing system. We are investigating whether the presence and extent of competition in the network (phonetic, phonological, lexical, and semantic) will have both behavioral and neural consequences. A series of experiments are investigating neural activation patterns under conditions of different types of competition including phonetic category competition, lexical competition, and semantic competition.