"The will...is the common stuff of all beings...consequently we possess it...with the animals, and even further on down." -Arthur Schopenhauer, On Psychology (1851)
"Selection is the very keel on which our mental ship is built" -William James, Principles of Psychology (1890)
"Desire is the actual essence of man" -Spinoza, Ethics (1677)
"Where the vulgar laugh, the philosopher admires" -Voltaire, The Philosophical Dictionary (1764)
Motivational states are the brain’s way of matching our behaviors to our needs and capacities: we eat when we’re hungry and sleep when we’re sleepy—but we forgo food and sleep when other things seem more important. Our motivations are central to who we are, but too often they spiral out of control causing addictions and other behavior and mood disorders.
We study the sexual behaviors of Drosophila, as they present the most tractable system in which we can clearly recognize the core features of motivation. There are three primary decisions we study in this system: i) how the male decides whether or not to court a female; ii) how the female decides whether or not to accept his courtship; and iii) how the male decides when, and under which circumstances, to terminate the mating. We have identified several circuit elements (small groups of neurons) that perform various motivational functions in each of these decisions, and many genes that work within these neurons to give them their specific properties. Many signs point to conservation of these mechanisms in vertebrates, including the central involvement of dopamine as a motivating cue.