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Video by Kevin D Schmidt

Dr. Robert Stickgold - Sleep, Memory, and Dreams: A Unified View

Air Force Research Laboratory

Dec. 22, 2023 | 01:16:00

Sleep, Memory and Dreams: A Unified View
Robert Stickgold, PhD
Harvard Medical School and Beth Israel Deaconess Medical Center, Boston MA USA

The benefits that sleep confers on memory are surprisingly widespread. For simple procedural skills – how to ride a bicycle or distinguish different coins in one’s pocket – a night of sleep or an afternoon nap following learning leads to an absolute and dramatic improvement in performance. Sleep also stabilizes verbal memories, reducing their susceptibility to interference and decay, processes that all too easily lead to forgetting.

But the action of sleep can be more sophisticated than simply strengthening and stabilizing memories. It can lead to the selective retention of emotional memories, or even of emotional components of a scene, while allowing other memories and parts of scenes to be forgotten. It can extract the gist from a list of words, or the rules governing a complex probabilistic game. It can lead to insights ranging from finding the single word that logically connects three apparently unrelated words, to discovering an unexpected rule that allows for the more efficient solving of mathematical problems. It can facilitate the integration of new information into existing networks of related information and help infants learn artificial grammars. Disruptions of normal sleep in neurologic and psychiatric disorders can lead to a failure of these processes.

Dreams appear to be part of this ongoing memory processing, and can predict subsequent memory improvement. The NEXTUP (Network Exploration to Understand Possibilities) model of dreaming proposes that dreaming aids complex problem solving by supporting divergent creativity, acting more by exploring a problem's "solution space" than by searching for the solution itself.

Key Moments in the video include:

Timeline of a good night’s sleep
Sleep physiology
Neuromodulation varies across the wake-sleep cycle
Regional activation in REM sleep - in the brain
Sleep improves what you learn
Learning rate saturates rapidly
Sleep enhances performance
Sleep keeps what is important
Sleep explains the world - weather prediction task
Dream content and memory evolution
Dream hacking and creativity
NEXTUP - Dreaming by sleep stage

Audience questions:

Trying to reconcile amnesiac patient’s paper - hippocampus must not have much to do with dreams then?
Could you say a sentence or two about what you mean by the ‘hippocampus is cut off’?
How do we - how does one measure information flow between the neocortex and hippocampus? What are those methods?
The word pairs in slow-wave sleep - if you were to wake those subjects up, are they having a subjective experience or dreaming? Or are those processes going on non-consciously?
I’m curious about the relationship between sleep and other periods of time where your mind is at rest - do these work together, are there separate functions?
Schema memory and extracting gist - where do you think (a schema) looks like in a brain? What does sleep do to form or update one?