Publisher Summary This chapter examines new insights on how the autonomic nervous system (ANS) and hypothalamus play a central role in the modulation of the ultradian rhythms of cognition, behavior, physiological functions that support psychophysiological states during both waking and sleep, mechanisms of hypothalamic integration and regulation of the body's major systems, and the translational neuroscience that can now help exploit these new discoveries. It has been known for almost one century that the ANS and the hypothalamus play a critical role, at the most elementary levels, in the regulation of vital physiological functions that help insure both the survival and reproduction of the species. Electrical stimulation of specific regions in the hypothalamus evoked classical autonomic responses in papillary diameter, salivation, heart rate, sweating, defacation, and bladder contractions. Electrical stimulation in the medial parts of the tuberal region produced parasympathetic effects on heart rate, gastric motility, and bladder tone. These early findings led to the seminal studies and conclusions that the anterior region of the hypothalamus is more concerned with parasympathetic mechanisms and that the posterior region is more concerned with the sympathetic mechanisms.