Determining the neurons and neuromodulatory pathways underlying the prefrontal control of visual signals

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Attention is the means by which we focus on behaviorally relevant information, to select and enhance a subset of sensory information for further processing while ignoring the rest. Several decades of research have implicated the prefrontal cortex (PFC) in the control of attention. Previous studies have showed that the manipulation of DA-mediated activity within the frontal eye field (FEF) part of PFC enhances the strength of signals in visual areas, raising the hypothesis that prefrontal control of attention is mediated by the actions of DA within the FEF. With support from the National Science Foundation, Dr. Noudoost and colleagues will pair electrophysiological recordings with local pharmacological manipulation of neural activity to reveal the neural mechanisms underlying DA's contribution to attention. One set of experiments will determine the functional characteristics of prefrontal neurons involved in the control of attention and visual signals. Using an improved technique, the prefrontal neurons projecting to visual areas will be identified, the content of their outgoing signal will be characterized, and the impact of this signal on representations in visual areas will be determined. A second set of experiments will use local pharmacological manipulations to directly examine the sufficiency of FEF DA to produce the perceptual and neural enhancements due to attention. Collectively, the proposed experiments aim to determine the neurons, neuromodulators, and interactions between prefrontal and visual cortices that underlie the flexible allocation of neural resources according to task demands; such an understanding will provide insight into how changes in these processes underlie the attentional deficits seen in mental illnesses, potentially indicating new diagnostic and therapeutic approaches.An imbalance in PFC dopamine (DA) has long been a suspect in the etiology of attentional impairments in mental illnesses such as attention deficit hyperactivity disorder, and dopaminergic drugs have played a central role in the treatment of these attentional impairments. A better understanding of the basic neural mechanisms underlying these processes will ultimately help develop diagnostics and treatments improving the well-being of affected individuals. Part of this proposal involves hardware development in collaboration with Neuralynx Company, which is located near the lab and is one of the foremost companies in data acquisition and signal processing industry, thus fostering a partnership between industry and academia for developing new tools and enabling new experimental techniques. Through the support of the National Science Foundation, three female scientists will be trained by the PI in cutting-edge neurophysiological research techniques and data analysis. They will also have the opportunity to publish their research in top tier academic journals, and present their research to colleagues at national and international conferences. The PI and colleagues will also present the results of this research in public presentations at the university, and widely advertised to the entire undergraduate population, thereby raising public awareness of and appreciation for scientific research. Attention is critical for learning, and thus a better understanding of the mechanisms of attention can also guide educational professionals toward more effective pedagogic approaches.