In neuroscience, the reward system is a collection of brain structures and neural pathways that are responsible for reward-related cognition and behavioral. What does this mean? For example, when something unexpectedly good happens to you, some parts of your brain are going to be activated, to allow you to understand what caused the good thing to happen.

Consider the way we make preference- or value-based decisions? In many examples, the amount of sensory information remains unchanged but the subjective value we assign to the different options changes. How to we weigh the pros and cons of the various alternatives. More generally how do we combine different sources of probabilistic information to make decisions that are more likely to lead to a reward?

Humans are inherently social. Although we may share some of the broader aspects of our social behaviour with more primitive species, human social behaviour is obviously more complex but no less important for our health and survival. How do we process social signals? What does it mean to be cooperative or competitive? What does it mean to have a reputation?

In view of the evolution of life and the many commonalities in all nervous systems, comparative neuroscience contributes substantially to the understanding of: - the human nervous system and senses, - to cognitive processes, - their pathologic conditions.

It is now clear that disorders of the mind are rooted in dysfunction of the brain, while neurological disorders interact strongly with psychological and social factors and often cause psychological symptoms. Yet classifying mental disorder is made on a sharp distinction between disorders of the mind and of the brain. It is timely to reconsider it.