Project Summary Little is known about the mechanisms that determine daily rhythms in rest-activity. We recently found that cells within the motor cortex can be synchronized to daily cycles of glucocorticoids. We hypothesize that daily suprachiasmatic nucleus activity and corticosterone secretion entrain circadian rhythms in cortical neurons and astrocytes to regulate daily patterns of behavior. We will take advantage of new high-throughput, machine learning and the ability to record and manipulate gene expression and calcium levels in specific cell types in mice. Combining these methods with two-color, real-time imaging of gene expression simultaneously in neurons and astrocytes, we will determine the roles of cortical neurons and glial in distinct daily activities.