The entorhinal cortex is a critical brain area for memory formation, while also the region exhibiting the earliest histological and functional alterations in Alzheimer's disease (AD). The entorhinal cortex therefore has been long hypothesized as one of the originating brain areas of AD pathophysiology, although circuit mechanisms causing its selective vulnerability remain poorly understood. Here we show that dopamine neurons projecting their axons to the lateral entorhinal cortex (LEC), critical