Abstract
This chapter provides a brief introduction to the way the brain works. It starts by describing the physical mechanisms used by neurons to send and receive electrical signals, and some of the experiments that led to the understanding of these mechanisms. It then describes how neurons are organized in networks and uses some particular structures in the brain, namely the brain visual cortex, to illustrate the signal processing that takes place in the brain. The chapter also covers, very briefly, the few known mechanisms that are used by brains to self-organize and create the structures that are present in fully developed brains. Mechanisms that lead to brain plasticity and the creation of memories are also examined, with a special emphasis of the synapse reinforcement process that is known as Hebb’s rule.