Based on research on the links between deep brain stimulation and its applications in the field of psychiatry, the history of techniques is of great importance in this book in order to understand the scope of the fields of application of electricity in brain sciences. The concepts of brain electricity, stimulation, measurement and therapy are further developed to identify lines of convergence, ruptures and conceptual perspectives for a materialistic understanding of human nature that emerged during the 18th century. In an epistemological posture, at the crossroads of the concepts of epistemes, as stated by Foucault, and phenomenotechnics, as conceived by Bachelard, the analyses focus on the technical content of the theories while inscribing them in the language and specificities of each era.