Can sleep help us unlearn biases and make our memories more positive?

Implicit biases are unconscious stereotypes that influence our judgments and decisions - like assuming a particular gender for a specific job role. But what if we could change these biases?

In this episode, we explore how manipulations of sleep might help reshape our implicit attitudes. We speak with Professor Xiaoqing Hu, a leading researcher in the use of Targeted Memory Reactivation (TMR) during sleep to alter implicit bias and make memories more positive. Xiaoqing shares his journey of applying Implicit Association Tasks (IATs) to sleep research, and how conflict biases, congruent vs. incongruent data, and task design play a role in measuring and modifying bias.

We also dive into the nitty gritty of memory consolidation in sleep — examining how REM and NREM stages contribute to emotional memory consolidation, and how recency vs. saliency affects which memories get updated.

Prof. Hu discusses his groundbreaking study demonstrating the ability to update unwanted emotional memories during sleep, and we explore the potential for applying this research to clinical populations. We also consider how individual schemas might influence the effectiveness of TMR across different people.

If you would like to find out more about Prof. Hu's work, please see the lab website here. You can find relevant papers below:

• Unlearning implicit social biases during sleep, 2015
• Updating memories of unwanted emotions during human sleep, 2022
• Targeted memory reactivation during sleep influences social bias as a function of slow-oscillation phase and delta power, 2023
• Reactivating cue approached positive personality traits during sleep promotes positive self-referential processing, 2024
• Aversive memories can be weakened during human sleep via the reactivation of positive interfering memories. 2024
• Disarming emotional memories using Targeted Memory Reactivation during Rapid Eye Movement sleep, 2024
• Targeted memory reactivation in REM but not SWS selectively reduces arousal responses, 2021

Glossary

IAT - Implicit Association Task - a test used to measure the strength of automatic associations between our concepts that we may not be consciously aware of.

TMR - Targeted Memory Reactivation - A technique used to modify memory processing, through the use of presenting cues (audio or smell) that were associated with learning, whilst a person sleeps. These cues can modify select memories and in recent research is being used in emotional memory.

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Host Professor Penny Lewis

Produced by Sophie Smith

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.

We're joined by Hongi Ngo, who developed a revolutionary technique for manipulating sleep oscillations during his PhD. Closed-loop Auditory Stimulation (CLAS), which uses bursts of pink noise which are carefully timed to a particular phase of an existing brain oscillation to either boost or dampen the target oscillation. It has been used to selectively strengthen or weaken memories, improve the immune response, reduce epileptic seizures, and even potentially to slow down age related cognitive decline.

Hongi tells us how he got got the idea for CLAS, explains how it works, and tells us about some of his existing studies. He talks about combining CLAS with Targeted Memory Reactivation (TMR) and discusses the ideas for future of brain modulation methods with techniques such as transcranial magnetic stimulation (TMS).

Some of the key papers discussed are:

Auditory closed-loop stimulation of the sleep slow oscillation enhances memory (2013)

Auditory closed-loop stimulation of EEG slow oscillations strengthens sleep and signs of its immune-supportive function (2017)

Thalamic spindles promote memory formation during sleep thrugh triple phase-locking of cortical, thalamic and hippocampal rhythms (2017)

Examining the optimal timing for closed-loop auditory stimulation of slow-wave sleep in young and older adults (2019)

Auditory stimulation during sleep suppresses spike activity in benign epilepsy with centrotemporal spikes (2021)

Shaping overnight consolidation via slow-oscillation closed-loop targeted memory reactivation (2022)

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.

How are memories represented in the brain and how can we model this?

Professor Anna Schapiro from University of Pennsylvania as we discuss her work on computational modelling of sleep and memory. In this episode, we discuss several kinds of Neural Network models as well as diving into the history of Jay McClleland's Complementary Learning Systems theory and Anna's recent work on combining neural network modeling with EEG.

Find out more about Anna Schapiro and her research group here.

Links to articles discussed in this episode:

• Why there are Complementary Learning Systems in the hippocampus and neocortex
• Methods for reducing interference in the Complementary Learning Systems model
• Self-recovery of memory via generative replay
• A unifying account of reply as context-driven memory reactivation

Host: Penny Lewis
Editor: Sophie Smith

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.

How does our sleep change as we age and what could this mean for memory and cognition?

In this episode, we discuss with Professor Rebecca Spencer her research exploring how our sleep patterns evolve over the course of our lives.

We explore the phenomenon of infantile amnesia - why we can't remember our earliest childhood experiences - and unpack the theories behind it. We discuss how hippocampal development changes as we age and how this links to memory consolidation and sleep. We also dive into Rebecca's work on emotional processing in children and how naps and sleeping are able to aid in emotional regulation.

Rebecca runs the Somneuro Lab at the University of Massachusetts Amherst. Find out more about Rebecca and her research group here.

Links to studies in the episode:

• Napping reduces emotional attention bias during early childhood
• Unhealthy diet is associated with poor sleep in preschool-aged children
• Television use and its effects on sleep in early childhood

Host: Professor Penny Lewis

Editor: Sophie Smith

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.

In this deep dive episode, we look at how sleep onset can help creativity.

With our amazing guest speakers, Professor Bob Stickgold, Dr Adam Horowitz, Professor Delphine Oudiette and Dr Celia Lacaux, we take a look at their work on creativity, dreams and N1 sleep.

Together, we discuss different definitions of creativity, what defines N1 and what it is about N1 that makes it prime time for creative processing.

Find out more about our guest speakers:

• Professor Bob Stickgold
• Dr Adam Horowitz
• Professor Delphine Oudiette
• Dr Celia Lacaux

Papers from the episode:

• Sleep onset is a creative sweetspot
• Replaying the Game: Hypnagogic Images in Normals and Amnesics
• Dormio: A targeted dream incubation device

Host: Professor Penny Lewis
Editor: Sophie Smith

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.

Sleepwalking, sleep talking, night terrors - how do they occur and why do some people have them more than others?

Join us as we discuss with Professor Francesca Siclari her work looking at non-REM parasomnias and the link to dreaming. We discuss the various forms that non-REM parasomnias can take, how they differ between adults and children and what the potential consequences of them can be.

Find out more about Francesca and her research group here.
Here are links to some of the studies:

• Conscious experiences during non-REM parasomnias
• Shared EEG correlates between non-REM parasomnia experiences and dreams
• Consciousness in non-REM-parasomnia episodes

Host: Professor Penny Lewis
Producer & Editor: Sophie Smith

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.

To kickstart season 3 of the Sleep Science Podcast, we have the lab behind the podcast, NaPS Lab, to answer some great sleep-related questions from our listeners. Thanks to everyone who sent in questions!

1. What is lucid dreaming? - Answered by Mo Abdellahi

• Lucid dreaming - Stephen LaBerge, 2009
• Induction of self awareness in dreams through frontal low current stimulation of gamma activity
• Real-time dialogue between experimenters and dreamers during REM sleep

2. Do dreams do anything for us? - Answered by Kyrillos Meshreky

• The brain as a dream state generator: an activation-synthesis hypothesis of the dream process
• Converging theories on dreaming
• Predictive coding under the free-energy principle

3. What types of memory does sleep help you consolidate? - Answered by Yan Wang

• The whats and whens of sleep-dependent memory consolidation
• The role of Sleep in declarative memory consolidation - direct evidence by intracranial EEG
• Sleep, Memory, and Plasticity

4. How does sleep change as you age? - Answered by Megan Wadon

• Sleep across the lifespan
• The architecture of early childhood sleep
• Normal sleep in children and adolescence

5. Why do adolescences sleep longer? - Answered by Martha Nguyen

• National Sleep Foundation’s sleep time duration recommendations
• Sleep in Children and Adolescents with Behavioral and Emotional Disorders
• Sleep quality and adolescent default mode network connectivity

6. Does the menstrual cycle affect our sleep? - Answered by Marta Wawrzuta

• Changes in sleeping energy metabolism and thermoregulation during menstrual cycle

7. How do the seasons affect our sleep? - Answered by Sophie Smith

• Circadian entrainment to the Natural Light-Dark cycle across seasons and the weekend
• Seasonality of human sleep: polysomnographic data of a neuropsychiatric sleep clinic

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.

For our end of season special, we have the rest of the NaPS lab in to answer a number of exciting sleep-related questions from our listeners. These touch on a range of different subjects from sleeps involvement in weight gain to alcohol's effect on sleep. Thanks to those who sent in questions!

List of Questions:

1. What is it in general anaesthetic that completely prevents a patient from waking up mid-surgery? Is this a similar state to being in a deep sleep or is this different entirely? 3:43

2. Can having daytime naps improve your memory? 5:24

3. Can a good sleep schedule help you lose weight? 6:40

4. Why do people tend to have a deeper sleep after drinking alcohol? 8:26

5. Can a lack of sleep really impact the way your brain works long term? 11:24

6. Why do children with ASD struggle to fall asleep and maintain sleep? 12:54

7. How does loud snoring or sleep talking wake up other people but not manage to wake up the person themselves? 16:13

8. How does drinking lots of caffeinated drinks affect our sleep wake cycle? 19:17

9. How does hibernation differ from a normal sleep in some animals? 21:05

10. When people say the term “just sleep on it” after a row or an emotional experience, is there any truth in this? Does sleep help you process emotions? 23:24

11. How much is sleep deprivation related to our immunity? 25:05


This episode was produced by Bella Mills-Smith

This recording is property of the sleep science podcast and not for resale

Check out our NaPS website to find out more about the podcast, our research and events.

This recording is the property of the Sleep Science Podcast and not for resale.