Mapping of the Mechanisms of Higher Functions

Acquisition of Magnetic Source Imaging System for Cognitive and Educational Neuroimaging (Supported by NSF BCS-0116150)

This project supported the acquisition of a multi-channel biomagnetometer system for Magnetic Source Imaging (MSI), to enable non-invasive recording of magnetic signals emitted naturally by the human brain during performance of sensory-motor, cognitive and linguistic tasks, and for constructing functional images of brain activation. We have accumulated sufficient data for constructing reliable maps of brain mechanisms associated with reading and phonological decoding in adults and in school-age children as well as kindergarten children learning to read. These discoveries led us to consider a host of experimental questions ranging from the layout of the mechanisms of oral and written language in the brains of bilingual and polyglot children and adults to questions regarding the formation of such mechanisms in the course of brain maturation and development, and to questions relating to specific spatio-temporal activation patterns underlying component cognitive and linguistic functions.

Integration of MSI/fMRI Studies of Reading (Supported by 5R01NS044826)

The primary goals of this study were to develop an interdisciplinary network addressing the integration of MEG and functional magnetic resonance imaging (fMRI) in order to evaluate a model of the cerebral mechanisms that support skilled reading. This model stipulates that printed word recognition is related to the development of a highly organized cortical system that integrates orthographic, phonological and lexical-semantic features of words. This system involves two posterior circuits in the left hemisphere (LH): a dorsal (temporo-parietal) and a ventral (occipito-temporal) circuit, along with a third circuit (inferior frontal gyms). A series of experiments were carried out involving healthy adults who received both MEG and fMRI while performing different reading tasks in order to (a) determine precisely which brain areas are functional components of the neural circuits supporting reading; (b) determine how the three putative neural circuits differ from one another in terms of the types of information processing performed by each.