Physiological need states, such as hunger and thirst, produce powerful motivations to obtain specific goals, such as food or water. Yet it remains unknown how the specificity of need-driven goal-seeking is achieved.
What drives water-seeking, but not food-seeking, when thirsty? How are specific physiological need states represented (e.g., caloric vs. fluid deficiency), and how are these representations then integrated with learned information about the external environment (e.g., cues predicting food vs. water availability) to facilitate fulfillment of the need?
Human neuroimaging studies implicate insular cortex as a unique site that performs this integration. Nevertheless, we still do not understand how insular cortex activity patterns guide decisions that will restore bodily homeostasis.
We recently developed a novel microprism-based experimental preparation that enables imaging intact insular cortex in awake behaving mice at cellular and subcellular resolution over months. We combine this approach with manipulations of molecularly-defined hypothalamic neurons that drive hunger or thirst to uncover neural circuit mechanisms by which hunger and thirst enhance cortical responses to food- and water-predicting cues. We are using this approach to elucidate how the specificity of need-driven goal-seeking is achieved.