Many projects are underway to develop advances in reasoning, cognition, consciousness management and thought transmission through the modeling of an artificial brain. This chapter gives several flagship projects which try to underpin mechanisms behind the human brain. In terms of sustainability, all these studies require a fertile crossroad intermeshing new ideas and concepts from biology, medicine, psychology, chemistry, computer sciences, networks, physics, chemistry and mathematics. They must investigate our nervous system from multiple perspectives including cells, development, anatomy, physiology, cognition, genetics, evolution, computation, medicine and information sciences. The chapter locates the areas of the brain involved in decision processes. To better understand the difficulty in managing technological challenges, the authors recall the basic principles and underlying mechanisms and structures used in the brain. Most importantly, they focus on the fact that most of them are already compatible with the concepts and constraints related to sustainability.