Nobel Conference Lecture -Sleep, Memory, and Dreams: Pulling it All TogetherOctober 1 at 9:45–10:20 a.m.

Nobel Conference - First Lecture 

Sleep, Memory and Dreams: Pulling It All Together

Robert Stickgold, PhD
Professor of Psychiatry
Harvard Medical School

Lecture description

All mammals, and arguably all animals, sleep. If we don’t, we die; it’s that simple. But sleep is a complex process, both mechanistically, with multiple sleep stages, and functionally, contributing to many aspects of our wellbeing. Arguably the earliest function of sleep was the offline processing of memories. Sleep, memory and dreaming are inextricably intertwined. While we sleep, our brain reprocesses the memories formed during the preceding day, stabilizing some and strengthening others. It extracts the gist from some and discovers patterns and rules in others. And it integrates these newly processed memories with older, related memories stored in associative networks, creating a network that adds meaning to the memories. Together, these processes constitute a mechanism of “memory evolution,” which continues throughout the lifespan, occurring in the background every night, outside of our conscious awareness.

But we also dream, achieving an altered state consciousness when memories are reprocessed in adifferent manner, with a different goal. While the memory evolution described above can be seen as examples of convergent thinking, where the brain takes specific information and seeks to alter it in specific ways, dreaming is a process of divergent thinking. Instead of , “how can we solve this problem?” it asks, “what sorts of questions could this new information help answer?” When we dream, the brain engages in Network Exploration To Understand Possibilities, which we shorten to NEXTUP, a process by which the brain takes a current concern seen in its memories from the day and seeks out older, often only weakly related memories, and tests whether these newly discovered associations might be helpful in solving our current concerns. As will be described, conscious dreaming is the only mechanism by which such associations can be tested.