Dissecting the Neural Circuits Encoding Positive and Negative Valence

Massachusetts Institute Of Technology, Cambridge MA

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Abstract

DESCRIPTION (provided by applicant): The two primary classes of emotional or motivational valence are seeking pleasure and avoiding pain. The ability to distinguish good and bad environmental cues is critical for survival, and perturbations in this ability can result in aberrat behaviors relevant to psychiatric disease. While the amygdala is known to be a region critical for processing motivational valence, a fundamental question in neuroscience is: How can opposing behavioral outputs be mediated by a similar neural mechanism? One likely possibility is that the processing of positive or negative motivation valence occurs with divergence into largely distinct circuits. Electrophysiological recording studies from the last decade provide compelling evidence that the amygdala could act as this initial divergence point. However, this hypothesis has not been directly tested. Here, we propose to directly test the hypothesis that positive and negative valence processing diverges at the basolateral amygdala, which projects to both the fear and reward circuits. We will test whether downstream projection targets define these different populations in both innate and learned associations, explore whether neural activity and synaptic plasticity are occurring preferentially in projection-defined neural populations, and identify novel targets in the fear and reward circuits. Our compelling preliminary data sets demonstrate the feasibility of applying multiple cutting-edge techniques to testing the specific hypotheses regarding causal relationships between specific neural projections and behavior, characterizing the cellular and synaptic mechanisms, and expanding our current knowledge of motivational circuitry. Specifically, this investigator has extensive expertise in projection-speciic optogenetic manipulations, electrophysiology, immunohistochemistry and pharmacological manipulations to study the neural basis of motivated behaviors. A successful outcome of the proposed research will establish a major conceptual advance in understanding the neural basis of positive and negative valence.