Memory loss is one of the most devastating afflictions of the human condition. Sleep is important for learning and memory because it improves memory consolidation – the transformation of new memories that are formed during wakefulness into stable memories that are integrated into pre-existing long-term memories. This is particularly true for memory for facts and events (declarative memory), which depends on brain regions in and around the human hippocampus. There is evidence that declarative hippocampus-dependent memories are consolidated during a sleep-stage called slow-wave-sleep, where large slow waves dominate brain activity. This consolidation is thought to be mediated by interactions between the hippocampus and brain areas in the frontal cortex. In this project, the researchers aim to study the effects of sleep on learning and memory in epilepsy patients implanted with depth electrodes for clinical monitoring. This setting provides a rare opportunity for direct recordings from inside the human brain, including at the level of individual neurons. The project also affords a unique opportunity to stimulate the brain during sleep, which is necessary for establishing a causal relationship between sleep and consolidation. This research will advance scientific knowledge on how specific sleep processes aid memory consolidation, and benefit society by training students in this integrative field, and developing new methods. The results may have implications for individuals suffering from neurological disorders affecting memory.