McCormick, DavidCollins, LindsayFrancis, John2021-07-272021-07-272021https://hdl.handle.net/1794/2651660 pagesAnimal behaviors result from complex network activity in the brain. Precise excitation and inhibition within these networks are partially regulated by neuromodulatory systems that regulate the behavior of other neurons, influencing brain processing and ultimately the animal’s behavior. This regulation is accomplished, in part, by the neuromodulators acetylcholine (ACh) and noradrenaline (NA). ACh and NA are produced and released by cholinergic and noradrenergic neurons, respectively, and have broad functions throughout the central nervous system. This project investigates the relationship between ACh and NA neuromodulatory activity and behavioral state with respect to arousal and behavior-dependent modes of neuromodulation. Using systems neuroscience techniques, such as intracranial viral injections and two-photon microscopy, this project offers novel insights into the dynamic relationship between ACh and NA activity and behavioral state in mice. First, I confirm previous findings of a strong relationship between neuromodulatory activity and arousal state, as measured by walking velocity, whisking, and pupil dilation/constriction. Second, I demonstrate that increases in both ACh and NA axonal activity closely track and precede the onset whisking bouts, but not walking. Last, I show that ACh axonal activity across the cortex is significantly less correlated during whisking and walking compared to stationary periods. This project furthers our current knowledge of the relationship between neuromodulatory activity and observable patterns of behavior by offering new evidence of more localized, state-dependent modes of neuromodulation.en-USCC BY-NC-ND 4.0NeuromodulationBehaviorArousalNoradrenalineAcetylcholineThesis/Dissertation336032015