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My research interests center on language and cognitive processes. In
particular, I am interested in examining the moment-by-moment details of
the processes employed in ongoing sentence comprehension and production,
with the goal of providing both conceptual and functional
neuropsychological models of these processes. Additionally, I am studying
the role of various aspects of cognition (e.g. attention, memory, visual
neglect etc.) and their potential impact on language function. Overall,
these interests incorporate several distinct lines of work in which I am
involved and focus on the language processing in adults, children and
language disordered populations. The ultimate goal of my research is aimed,
first and foremost, at designing a comprehensive model of normal language
processing and in addition, applying this knowledge to those populations
who exhibit specific difficulties in one or more aspects of language
function.
One focus of my research is on the cerebral organization of
language. Specifically, I am attempting to detail the roles of the two
hemispheres at various stages of language processing (e.g. lexical access,
syntactic parsing, discourse processing). This research involves two
separate approaches- each devoted to the ultimate understanding of the
intra-hemispheric contributions of the left and the right hemispheres
during on-going sentence processing.
The first approach involves research with patients who have
sustained damage to either the right or left hemisphere. These populations
allow for the separation of specific language subsystems that are not
unintrusively separable in unimpaired populations. I am currently
investigating (a) the use of context (both sentential and prosodic) at the
level of lexical access and structural parsing; (b) the ability to use
grammatical constraints in real time during the processing of long distant
dependency relations {those involved in structurally defined
gaps, pronouns and reflexives}; (c) the levels of analyses
that are used during these automatic acts of co-referential processing; and
(d) the role of prosody in lexical and structural parsing, particularly
with respect to the time course of the role of the right hemisphere in
language processing.
My second approach attempts to detail the cerebral organization of
language in unimpaired populations. I have been involved in the
investigation of some of these phenomenons using brain imaging techniques
such as functional magnetic resonance imaging (fMRI) and evoked response
potentials (ERP). In collaboration with Dr. David Swinney & Dr. Gregory
Hickok we are attempting to detail the neural regions contributing to (1)
the processing of various complex sentence types in hearing subjects and
(2) the neural contribution of deaf speakers of American Sign Language during
comparable language tasks. The ERP research has been conducted in
collaboration with Dr. David Swinney, Dr. Helen Neville and Dr. Enriqueta
Canseco-Gonzalez. This project attempts to disentangle the semantic and
syntactic components contributing to several specific brain electrical
activity patterns (early LAN, N400, P600), proposed to be associated with
grammatical processing.
My other research focus involves studies with unimpaired populations
and centers on the various processes through which the human parser embarks
during on-going sentence processing. Similar to those interests described
above, my interest in normal processing capacities spans a number of
levels. I have explored the nature of context effects (semantic,
plausibility, etc.) on lexical access; the level of analyses involved in
co-referential processing; lexical ambiguity resolution and structural
co-reference capacities. These studies focus on the processing capacities
of unimpaired college and aging populations as well as the developmental
capacities of pre-school age children in all of these stages of language
processing. On a separate but related vein, I am studying methodological
issues involving the sensitivities of various on-line experimental
techniques in language processing with a particular focus on what various
methods can and cannot tell experimenters about the processes in which they
are investigating.
All of these approaches from the various disciplines described above
(aphasia, functional imaging, and work with unimpaired adults and children)
will fit together to form the crucial components of a comprehensive model
of language processing which is currently under development.
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