The most powerful and essential force in the central nervous system is 'generalized CNS arousal' (Harvard University Press, 2006). The first part of the talk will give its precise definition and evidence for its existence. Also, a quantitative behavioral assay for mice will be shown, a computer-controlled assay. Then we will look at how generalized CNS arousal mechanisms impact the hypothalamic neurons that are responsible for regulating the first-worked-out mammalian behavior, a female sex behavior (older work reviewed in Drive, MIT Press, 1999). We are currently working on 4 chemical systems that manage the effect of generalized arousal on sexual arousal: histamine (through H1 receptors), norepinephrine (through alpha 1b receptors), opioid peptides (through mu receptors ) and prostaglandin D. Finally, we will consider raising CNS arousal after brain damage, and the possible usefulness of using non-linear dynamics (BioEssays, 2007) to design pulse trains for deep brain stimulation. All of these studies deal with what we consider to be the most fundamental property of vertebrate nervous systems.