Defining the Neural Circuits of Attention Control: A New Hypothesis

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PROJECT SUMMARY The recent discovery of a putative attention control area shows that there is a fundamental gap in our understanding of the neural mechanisms of attentional control. The existence of this conceptual gap constitutes an important problem because, until it is filled, we will not be able to explain a key cognitive function, the flexible selection of information according to current demands and interests, nor to appropriately treat impairments of attention. The long-term goal of this research is to understand how sensory processing and cognitive control mechanisms interact to generate intelligent behavior. The overall objective of this proposal is the determination of the functional organization of the neural circuits supporting attentional control and the mechanisms they are implementing to achieve this function. The experimental model utilizes brain-wide imaging of functional specializations for attention followed by the targeted determination of local neural processes. It allows to test the central hypothesis that there is at least one area in the temporal lobe that is critical for the endogenous control of visual attention. The rationale for this proposal is that completion of the research will re-define endogenous attentional control circuits, which is of direct relevance to neurological practice. The central hypothesis will be tested through four specific aims: Aim1 will determine, using whole-brain functional magnetic resonance imaging (fMRI) and targeted single-unit electrophysiology, the functional specializations of visual attentional control areas and test the working hypothesis that endogenous attention is controlled by specific set of areas sharing a similar organization across species. Aim 2 will determine population codes and dynamics controlling attention and test the working hypothesis that a temporal and a parietal area control the focus of attention in similar ways, yet with differential coupling to its expression into action. Aim 3 will determine the network structure of attentional control areas and test the working hypothesis that the three regions of attentional control are selectively interconnected to form an integrated network of attentional control. Aim 4 will determine the neural mechanisms of visual attentional control over sensory areas and behavior through artificial activation and inactivation during attentive visual processing and test the working hypothesis that a recently discovered temporal lobe area exerts attentional control. The approach is innovative, because it challenges long-held views on the neural circuits of attention and because it introduces a new multi-modal experimental paradigm that promises to shift the approach to neural systems analysis in the cognitive neurosciences. The proposed research is significant, because discovery and characterization of a new attentional control area will fundamentally alter current concepts of attention and brain organization, and because it overcomes a critical barrier in the cognitive neurosciences, the difficulty to bridge between large-scale investigations of functional brain organization with the determination of local neural mechanisms. The project is of direct relevance to neurology and is expected to have a positive impact on the understanding, diagnosis, and treatment of attentional control deficits like hemispatial neglect.