R E S T L E S S R E M S L E E P I M P E D E S O V E R N I G H T A M Y G D A L A A D A P T A T I O N

( W A S S I N G E T A L . , 2 0 1 9 )W E E K 9 : K E L L Y D O U D E L L

M A R C H 1 0 , 2 0 2 1

W H A T I S R E M S L E E P ?( R A P I D E Y E M O V E M E N T )

• 5th stage of sleep à starts after ~90 minutes of sleep & occurs 1-4x/night

• Activation in limbic system, amygdala, and dACC• Inhibition in locus coeruleus

• EEG similar to theta waves while awake• Main difference is muscle atonia

• Function:

• Learning and memory consolidation in hippocampus• Dreaming state

• Brain development (motor and sensorimotor system)• Appetite hormone regulation (leptin and ghrelin)

• Alcohol, nicotine, & marijuana decrease REM sleepPeever & Fuller, 2017

R E S T L E S S R E M S L E E P • REM sleep with a high number of phasic events or arousals

• More arousals and stage transitions in REM sleep = more restless REM

D R . R I C K W A S S I N G

E X P L A I N S S T U D Y

M E T HO D S• Participants: N=29 (15 females)

• Preparation (1 week prior):• Intake Interview• Structural MRI-scans

• Karaoke-style audio recordings• Odor-perception and odor-discrimination tests• Polysomnography adaptation night

• Olfactometer• 6 capsules connected (4 with odor, 2 no odor)

• 2 capsules per participant

• 30-min test with 40 trials• 1 of 4 odors (or no odor) presented for 3s• Likert scale question for perception of

odors

Odor-Perception Test

• 45-min test with 36 trials• Presented with 3 odors and 2 are same, 1

is different• “Which odor was different?”

Odor-Differentiation Test

M E T H O D S

• Listened to karaoke audio recordings before and after sleep for 2 runs of 10 stimuli • Self-conscious = own singing (CS+)• Non-self-conscious = professional singer (CS-)

• Perceived emotional intensity• 1-back task with letters

fMRI scans

• Adaptation night & Night in between emotion inductions

• 245-channel net & Respiratory belts• 4 sleep episodes

Polysomnography

Singing Silent Night - YouTube

R E S U L T S• (A) Own-singing stimuli > other-singing stimuli

• (B) Overnight decrease in amygdala reactivity is proportional to total duration of REM episodes (but not TTR episodes)

• Longer lasting TTR episodes and more spindles boosted effect of subsequent REM episode duration

• Stronger with increasing duration of uninterrupted REM sleep

• (C) TMR during REM episodes using own-singing stimuli odor (CS+) during wakefulness:

• Added to favorable effect of total duration of REM episodes

• Enhanced adverse effect of REM episode interruption density

**REM sleep can support overnight regulation of amygdala reactivity

à NREM sleep supports REM sleep in the process

à Restless REM sleep contributes to hyperarousal in insomnia

• TTR = Transition to REM (interval between slow-wave and REM sleep)• TMR = Targeted Memory Reactivation

C L A S S D I S C U S S I O N Q U E S T I O N S

Methods:

• REM sleep in day vs. night sleepers? (Betty)

• What other emotions (other than self-conscious)? (Rebecca)

• Other forms of memory reactivation (visual) have same effect? (Sarah)

• Comparison with animal sleep research? (Hannah)

REM Sleep and other disorders?

• Anxiety and Depression interrupt REM sleep? (Giana)• Prescriptions for these disorders? (Nicole)

• Other physical health problems? Who is most at risk for restless REM sleep? (Hannah)

Implications

• COVID-19’s effect on taste and smell à impact memory and emotional regulation? (Liz)

R E F E R E N C E S• Peever, J., & Fuller, P. M. (2017). The biology of REM sleep. Current

Biology, 27(22), R1237-R1248.

• Wassing, R., Lakbila-Kamal, O., Ramautar, J. R., Stoffers, D., Schalkwijk, F., & Van Someren, E. J. (2019). Restless REM sleep impedes overnight amygdala adaptation. Current Biology, 29(14), 2351-2358.

• Rick Wassing, MSc PhD-C: Restless REM Sleep Contributes to Hyperarousal In Insomnia – YouTube

• Singing Silent Night - YouTube