A number of specific issues concerning the structure of lexical forms and their relation to grammatical, morphological and semantic information are being pursued. These issues are addressed through research with brain-damaged and normal subjects. The analysis of the impaired performance of brain-damaged subjects provides a window into the organization and structure of normal language processes and their possible neural substrates. Some of the specific issues currently being pursued are: 1) the structure of lexical-orthographic representations; 2) the representation of grammatical class information; and 3) the representation and processing of morphological structure. A related set of interests concerns the organization of the naming, reading and spelling systems as revealed through the analysis of acquired anomia, dyslexia, and dysgraphia. For example, what are the implications of the production of semantic errors in naming, reading and spelling for the structure of these processes? That is, what can we learn about the structure of semantic representations from the distribution of semantic errors in various word recognition and production tasks? Other issues being pursued in this area include 1) the organization of lexical and nonlexical processes in pronouncing and spelling words, and 2) the role of the graphemic buffer in reading and spelling.A more recent interest in my laboratory concerns a set of problems about visual perception and attention that have arisen from the investigation of patients with visual-spatial neglect and other visual processing neurological disorders. Visual neglect is a disorder in which a patient fails to attend or respond to a spatially-specific part of a stimulus. In our earlier research we have shown that there are several different types of visual-spatial neglect resulting from damage at different levels of visual representation. In our current work we are pursuing several questions: 1) what can we learn about the structure of different levels of representation in object recognition from the performance of neglect and agnosic patients? 2) what is the fate of the neglected part of a representation? and, 3) what is the role of attention at different levels of visual representation?
Research in my laboratory has principally focused on problems of lexical processing -- to understand the organization and processing structure of the lexical system and the nature of lexical representations.
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