Scientists have believed for years that memories are strengthened during sleep through a conversation between the cortex, thalamus, and hippocampus. Direct evidence in humans has been almost impossible to obtain, because measuring it requires electrodes inside the brain.
Researchers at Kennedy Krieger Institute and Johns Hopkins Medicine have now done it. Using simultaneous intracranial recordings from the medial orbitofrontal cortex, thalamus, and hippocampus in 19 patients with epilepsy, they showed that slow oscillations in the orbitofrontal cortex organize the faster rhythms in all three regions during sleep, and that stronger coordination predicted better memory the next morning.
