Follow-up course to Introduction to the Brain. This course explores the neural mechanisms that mediate motivated behaviors. We will begin by reading a seminal book on the topic, Motivational Systems, by Frederick Toates, to introduce concepts such as goal-directed behavior and incentive motivation, and heuristics regarding how behaviors can be broken down into motivationally distinct components. We will examine how the "pull" of incentives in the external world compares and relates to the "push" of drive states within the organism, and how these concepts guide our approach to understanding the biological bases of motivation. We will then consider the neuroanatomy and neurochemistry of behaviors directed toward keeping the physical homeostasis of the organism in balance: drinking, feeding, temperature regulation, biological rhythms, and the repercussions of stimuli or states in which these systems are altered. This will be followed by discussions of "non-homeostatic" behaviors like sex, parental behavior, and aggression, and the manner in which these behaviors obey very similar neurochemical rules. We will then consider how these "natural" examples of motivated behaviors relate to pleasure, reward, and drug addiction.