Sleep

Sleep represents a natural and reversible state of decreased consciousness. Likely conserved across all vertebrate species (including mammals, birds, fishes, and reptiles), sleep’s adaptive role appears essential, yet its function is incompletely understood.  Sleep has been thought to save energy, repair tissue damage, regulate metabolic function, and support immune function.  From the brain’s perspective, sleep has been proposed to play a role in clearing toxic free radicals and amyloid proteins, rebuilding energy stores, and supporting memory consolidation.

Our current research aims to understand how memories are consolidated, or strengthened, during sleep.  Animal studies (e.g. recordings from hippocampal place cells) demonstrate that information that is encoded during the day is reactivated during sleep in high fidelity, replaying events in a spatially and temporally specific manner. Similarly, in humans, sleep may support consolidation by reactivating, processing, and integrating temporary memories into long-term storage.

By recording the brain activity of epilepsy surgical patients during sleep, we seek to understand how the hippocampus and related structures stabilize newly encoded information.  In particular, because we are able to record on the single cell, local field potential, and network level, we seek to understand how the coordinated activity of slow waves, sharp wave ripples, and spindles during sleep relate to behavioral outcomes.

Faculty: György Buzsáki, Sydney Cash, Orrin Devinsky, Eric Halgren, Daniel Friedman, Anli Liu, Thomas Thesen