Sleep, Memory, and Learning: What We All Need to Know. What We Need to Know

Transcription

1 Sleep, Memory, and Learning: What We All Need to Know Robert Stickgold Harvard Medical School Beth Israel Deaconess Medical Center Boston, MA Dr. Stickgold receives research funding from and consults to Actelion Pharmaceuticals, Merck Co, and Sepracor Inc What We Need to Know Sleep does not merely cure sleepiness Sleep is critical for psychiatric health Sleep is critical for emotional regulation Sleep is critical for understanding what we ve learned

2 Sleep Doesn t Just Cure Sleepiness A Good Night s Sleep Wake I/REM II III IV Sleep onset SWS REM sleep Stage 2 NREM 11 PM 1 AM 3 AM 5 AM 7 AM

3 Sleep Physiology ACh NE 5-HT Ach: NE: 5HT: Neuromodulation Varies Across the Wake-Sleep Cycle Active Wake Quiet Wake SWS acetylcholine (scopolamine, atropine) norepinephrine (MAO inhibitors) serotonin (SSRIs, LSD) REM

4 Regional Activation in REM Sleep Poor Sleep can Exacerbate, Trigger, or Even Cause Psychiatric Disorders

5 ADHD and Sleep Apnea No Treatment ADHD & Apnea Methylphenidate Adenotonsillectomy Control Children No Treatment Huang et al. (2007) Sleep Medicine 8, Month Follow-up ADHD-RS hyperactivity subscore ADHD-RS inattention subscore ADHD-RS total score Controls Controls Controls Percent of Patient Baseline No TX Methylphenidate Surgery No TX Methylphenidate Surgery *** No TX Methylphenidate Surgery *** ***p< compared to baseline p<.01 compared to MPH Huang et al. (2007) Sleep Medicine 8, 18-30

6 Sleep is Critical for Emotional Balance QuickTime and a decompressor are needed to see this picture. Seung-Schik Yoo Ninad Gujar Matthew Walker Emotional Memory After Sleep Deprivation Neutral, Negative, Positive Sleep No Sleep Yoo et al. (2007) Curr Biol 17, R

7 Negative Stimuli mofc amygdala QuickTime and a decompressor are needed to see this picture. Yoo et al. (2007) Curr Biol 17, R Emotional Memory After Sleep Deprivation encoding test Sleep Sleep Sleep No Sleep Sleep Sleep

8 Memory Recognition Emotional Memory After Sleep Deprivation Sleep Deprived positiv e neutral negativ e Sleep Processes Different Kinds of Memory in Different Ways

9 # Sequences / 30 sec Sleep Consolidates Motor Learning Sequence Matthew Walker Tiffany Brakefield Alexandra Morgan Sleep Enhances Performance p< p< PM 10AM 10PM 20 10AM 10PM 10AM SLEEP SLEEP

10 % Change (relative to 20 min Sleep Consolidates Episodic Declarative Memory Verbal Memory Task Word Lists Door House Ledge Glass Open Breeze Pane Frame Curtain Shade View Window Jessica Payne Ruth Propper D-R-M: 12-Hour Deterioration 15 Sleep Wake * -45 * -60 Studied words Gist words

11 Subjects gaining insight Sleep Enhances Insight Number Reduction Task Ulrich Wagner Jan Born Wagner et al. (2004) Nature 427: 352 Development of Insight % 40% 20% 0% Wake/ Day Wake/ Night Sleep/ Night

12 Sleep Enhances Infant Learning Artificial Grammar Learning pel-wadim-jic pel-puser-jic pel-chila-jic vot-roosa-rud vot-wadim-rud vot-plizet-rud pel-wadim-rud vot-roosa-jic pel-puser-rud vot-wadim-jic pel-chila-rud vot-plizet-jic Rebecca Gomez Richard Bootzin Lynn Nadel Gomez et al. (2006) Psychological Science 17: Babies (15-mo) Learning the Rules pel-wadim-jic vot-wadim-rud pel-wadim-jic vot-roosa-rud vot-roosa-rud pel-puser-jic vot-wadim-rud pel-puser-jic pel-chila-jic vot-plizet-rud pel-chila-jic vot-plizet-rud pel-wadim-jic pel-rotak-jic pel-chila-rud vot-roosa-rud vot-kodak-rud vot-plizet-jic

13 Viewing Time (s) Artificial Grammar& Infants 9 p=.0001 p=.024 Old New Match No Match Nap No-Nap Nap Control Gomez et al. (2006) Psychological Science 17: Sleep Enhances Adult Learning If you re not dreaming about geometry Emily Hogeland

14 Harvard College Organic Chemistry (percentile rank in class) 100% The Real World 90% r 2 = 0.86 p = y = -17x % 70% 60% 50% Std. Dev. of TST 2-5 Nights prior to testing (hr) And school start times At puberty, children undergo a biological phase delay. Their biological clock is altered so that both sleep onset and morning wake times are shifted to later times. Thus, getting an adolescent to go to bed at 10pm might be like trying to get you to bed at 8 or 9pm - It just doesn t work!

15 It s So Easy! Of all the interventions aimed at improving learning in children that we discuss, this may be both the easiest and cheapest. By educating parent, children, teachers and administrators, we may be able to improve children s sleep, and I am confident that if we do, we will improve their learning. If we can get them to listen! Part II: The Mind at Rest

16 Improvement (sec) Dream Content Predicts Spatial Memory Consolidation NREM Napping NYTime.com April 22, 2010 Erin Wamsley Matt Tucker Train ± NREM Nap Test 12 pm pm 150 p= WAKE (n=16) SLEEP (n=16)

17 Improvement (sec) Improvement (sec) Improvement (sec) Improvement (sec) Train ± NREM Nap Test 12 pm pm QUESTIONNAIRE p= p= Not maze related Maze related p< n.s WAKE (n=16) SLEEP (n=16) -100 WAKE SLEEP Train ± NREM Nap Test 12 pm pm REPORTS QUESTIONNAIRE Not maze related Maze related p= Not maze related Maze related WAKE SLEEP WAKE SLEEP

18 Improvement (sec) Quiet wakefulness (useful?) I was thinking about the game that I used to play in high school, Counter-Strike, because of the same layout... and also I was just planning, and trying to remember the maze and trying to figure out the route... thinking [about] what we have to do in the second maze test... wondered if it was going to be, like, the same No maze Maze related n.s. WAKE SLEEP Dream reports (useless?) I was thinking about the maze and kinda having people as check points, I guess, and then that led me to think about when I went on this trip few years ago and we went to see these bat caves, and they're kind of like, maze-like Looking for something in a maze Just hearing the music from the task Sleep-Dependent Memory Processing: Using the Whole Brain Hippocampus Neocortex DREAMING Stabilization and enhancement Salience selection Rule and gist extraction Network integration Narrative development (navigation) Future projection Theory of mind Who decides what we dream about?

19 SNIP & FIT: A Model of the Resting Mind SNIP & FIT The Functional Incompleteness Theorem (FIT) The brain has evolved to identify cognitive processes that fail to achieve their goals (i.e., to reach completeness) and then, attempts to complete them, through continued off-line processing Sustained Non-directed Incomplete- ness Processing (SNIPping)

20 Nonconscious SNIPping Senior moments memories recovered without awareness of continued search Insights - typically begin with a problem that has reached a dead end Sleeping on a problem an answer without awareness of any decision-making process SNIPping and the Default Network (When nothing s going on ) Episodic recall What haven t I finished? Theory of mind What did he mean by that? Future projection What am I going to do next? or at least for the default default network

21 Psychiatric Disorders of SNIPping Obsessive-compulsive disorder Autism spectrum disorder PTSD (pathological inability to complete) Anterior cingulate incompleteness error-signaling incompleteness-signaling signaling failures failures FITful Sleep Sleep plays a special role in SNIPping Sleep onset and 4AM awakenings Sleep-dependent search for what s important: Emotional scenes Gist extraction Insight & rule extraction

22 FITful Dreams Dreaming play a special role in SNIPping Wish fulfillment (Freud) Threat avoidance (Revonsuo) Incomplete arrangements (Hobson) Maze-related dreams PTSD dreams (not!) Summary Dreams appear to be a manifestation of sleep- dependent memory processing. But similar forms of off-line memory processing appear to occur during wake as well, in the form of SNIPping. Thus, sleep-dependent memory processing and dreaming may be continuations and refinements of this daytime processes, both in and out of consciousness. And, arguably, much of what we learn we learn during this offline processing.

23 Together, these systems carry out what may well be the most sophisticated function that the human brain performs the building of a model of our world that provides clues to the course of our future and creates the meaning within our life. QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture.

24