Identifying and recognizing visual objects are crucial skills that enable to interact with the environment adequately. Most of the time, these processes are rapid and effortless. However, recognition is the final outcome of complex processes, including the creation of representations of visual objects and their consolidation into memory, which mechanisms and neural correlates remain largely unknown. The present work reports four studies, aiming at better understanding visual learning, and testing more specifically the role of experience and sleep on visual learning. In particular, this works highlights a crucial role for the hippocampus in visual representation formation, for both 3D-objects and faces. This work also shows evidence that sleep may play a critical role in the consolidation of memory traces for faces, making human's brain more resistant to misleading information. By combining behavioral and neuroimaging approaches, this thesis provides new insights into the cognitive and brain mechanisms underlying visual learning.