Cortical Somatosensory Processing in Humans

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The central thrust of my research program is to characterize the spatial and temporal organization of human somatosensory cortex. To this end, I have used functional magnetic resonance imaging (fMRI) to functionally localize cortical regions in the human brain that process somatosensory information. For example, I have examined the representation of the fingers in human somatosensory cortex (i.e., somatosensory somatotopy) and probed the neural substrates of the tactile motion aftereffect. I have also developed psychophysical techniques to investigate human tactile working memory. Most recently, I have developed computational models of tactile working memory. In the current proposal I will use ultra-high field fMRI (7T), high-density ERP (event-related potentials), as well as computational modeling to continue these investigations. fMRI will allow for highly detailed study of spatial organization and ERP will make it possible to study the temporal relationships between the regions investigated with fMRI. I will continue examining the functional characteristics of somatosensory cortex and related parietal regions by investigating how spatial (for example, location) and temporal (for example, frequency of stimuli and timing relations between stimuli) aspects of tactile stimulation modulate activity in these regions. I will also continue ongoing psychophysical tactile working memory experiments with the aim of importing such techniques into a neuroimaging context (both fMRI and ERP). Finally, I will continue to investigate computational models of tactile working memory The work outlined in this grant will contribute not only to our understanding of the nature of the signals (the cortical origins of these signals and their timing relationships) arising within human parietal and associated cortex during tactile stimulation, but it will also provide information about how the various cortical regions involved in somatosensory perception interact and how such signals are maintained in these brain regions during tactile working memory tasks.