One of the most common ways by which scientific thought and communication adapt themselves to extra-scientific discourses is science popularization. And one the most common features of science popularization lies in its use of metaphors and analogies (Jeanneret ; Mussolff). This fact is linked to the necessity to translate abstract concepts and styles of thought in a language comprehensible for anyone and to the fact, established by the cognitive sciences, that metaphors might be at the heart of our conceptual system (Lakoff & Johnson). This presentation aims to explore this hypothesis, from the example of the French edition of the « Brain Awareness Week », an annual event of popularization of the neurosciences organized in North America and Europe since the 1990s. The « Semaine du cerveau » consists in open houses at neuroscience labs, lectures on brain-related topics, exhibitions about the brain, displays at libraries, theatres and community centers, classroom workshops… In a first part, we will see that metaphors, along with others means, are indeed central to the discourses of the neuroscience popularizers. Hence, they have a great influence on our basic, extra-scientific narratives concerning the brain. But they are not so numerous and diverse. They can be gathered in a few items : brain as a black box or a fortress which has to be opened ; brain organisation as neural highways ; brain as a global positioning system ; brain as a super computer, etc. This kind of rethoric draws its origins from cultural clichés but above all from « theory-constitutive metaphors » (Boyd) used by neuroscientists. In a second part, we will try to explain this surprisingly narrow range of metaphors by identifying several constraints on their uses in popularization discourses. These depend at least on four parameters : the scientific context (Fox Keller) ; the training and the biographical trajectory of the neuroscience popularizers, which make them more or less comfortable with the use of metaphors (researchers vs. trained scientific mediators) ; the representation among these popularizers of their audience ; the sociocultural contexts (Kövecses), which can promote certain metaphors for good or, more often, bad reasons All these elements shape a great deal of popularization narratives, and consequently the layman understanding of neuroscience in today society.