Hanna Damasio, MD - US grants

The Core project is the central resource of the Program. It encompasses six Subcore Units, which perform the following specific operations: (a) identification, screening and induction of patients into the Database/Registry; (b) performance of basic neuropsychological studies of each patient at the time of screening and induction; (c) performance of neuroimaging studies and neuroanatomical analysis at both the screening/induction and the chronic stages; (d) central data management for neuropsychological and neuroanatomical data; (e) data analysis as needed by different projects; (f) development of new methodologies and procedures as needed, and (g) monitoring of data quality and research progress. All of these functions are continuous over time.

The overall goal of this project remains the delineation of neural systems underlying language, by means of special experiments conducted in patients with focal brain damage. The first specific aim is to map the neural basis of the lexicon. The studies focus on the systems supporting lexical access, which we hypothesize to be based on left temporal cortices. The second specific aim relates to the processing of visuomotor linguistic signs, such as those used in American Sign Language (ASL). We will investigate the neural systems required for representing and accessing such signs, by studying the acquisition of ASL lexicon in hearing patients with a wide range of focal damage in left and right hemispheres. Also, we will continue to assess the clinical value of traditional diagnostic categories of aphasia, by investigating the consistency of anatomo-clinical correlations in our database, and to study the neural basis of auditory perception. The results will contribute to a more precise formulation of the neural basis of language, at systems level, and in particular, to further specification of the neural and cognitive architectures pertaining to lexical access and lexical representation. The results will shed light on the diagnosis and physiopathology of the aphasias, and assist in the development of programs to rehabilitate the large number of stroke and head injury victims who develop language impairments. Our approach capitalizes on the unique opportunities afforded by the study of adult humans with focal brain injury, and seeks to advance knowledge of language at both the neural and psychological levels.

Patients with word retrieval defects for entities from varied conceptual categories or for actions, are still capable of retrieving many lexical items. The question thus arises as to which neural structures permit this "residual" word retrieval, a question that is important both to further our understanding of the neural basis of language processing, and to elucidate mechanisms of brain plasticity in the recovery from brain injury. In this project we will test the following three alternative hypotheses: (1) that residual word retrieval depends on the activation of regions in the right hemisphere, homologous to the ones activated in the left hemisphere in normal English speaking subjects; (2) that the residual capacity correlates with activation in the immediate anatomical surround of the damaged area; or (3) that the residual word retrieval depends on both activation of the right hemisphere homologues and the surround of the damaged area. We will study 40 brain damaged subjects in four PET experiments, involving the retrieval of words denoting concrete entities, as well as words denoting actions. Evidence from this project will be of great value to understand the process of recovery from brain injury in patients with English aphasia, as well as those with ASL aphasia, and to design effective rehabilitation strategies.

Diffusion of water, as detected by MRI, can reveal microscopic structures in tissues. Understanding of these phenomena requires extensive simulations as well as theory and experiments.

The Core project is the central resource of the Program. It encompasses five Core Units, which carry out the following operations: (a) Patient Registry, which regards the identification, screening and induction of subjects into the Registry, and the central Database and data management for neuroanatomical analysis at both the screening/induction and chronic stages; (c) performance of basic neuropsychological studies at the time of screening/induction and at the chronic stage; (d) statistical analysis as needed by different projects; (e) monitoring of all matters pertaining to subject confidentiality, informed consent procedures, data quality and research progress. These operations, which are essential for the execution of all studies in our Program involving humans, are carried on continuously. They have been carried out smoothly, in all aspects, for the duration of the Program, and remain unchanged for the forthcoming funding period. The investigators in the Program have also continued to develop new techniques required to improve the quality of neuroanatomical and neuropsychological data gathering and analysis. As a result, new products are now available, to this research group and to others, for cognitive neuroscience research (e.g., single-channel tissue segmentation, 3- dimensional lesion analysis in a standard anatomical space (the MAP-3 technique)).

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. N/A