Lesions of primate primary visual cortex (V1) lead to loss of conscious visual perception, and are often devastating to those affected. Understanding the neural consequences of such damage may aid the development of rehabilitation methods. In this rare case of a Rhesus macaque (monkey S), likely born without V1, we investigated the brain structures underlying residual visual abilities using multimodal magnetic resonance imaging. In-group behaviour was unremarkable. Compared to controls, visua...