 Brain function relies on the communication of hundreds of billions of neurons through electrical signals. Those signals are generated thanks to the flow of ions through proteins in the cell membranes. Those proteins are known as ion channels and are responsible for recognizing and processing environmental stimuli. Neurons in action is about the molecular elements that allow neuronal communication, focusing on the processes of learning and memory and with particular emphasis on some specific ion channels. In the course, we will also approach from a historical perspective the techniques that have been used for understanding the brain function and structure. In addition, we will visit a research laboratory and there will be a synophorum session. To conclude the course, we will share our particular vision of the human brain and discuss how it has changed during the Neuron in action course.