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!
Want to find out more about the team and the lab? Check out our website here.

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: Between Freud, predictive processing, and psychedelic research 
• 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
• The Relations Between Sleep, Personality, Behavioral Problems, and School Performance in Adolescents 
• Sleep quality and adolescent default mode network connectivity 
• Sleep loss, learning capacity and academic performance

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

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

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.

In this episode, we talk with Professor Chiara Cirelli from the department of Psychiatry at the University of Wisconsin.

We begin by hearing about how she first got interested in sleep research, and particularly about her time as a medical student at the University of Pisa where she worked on the noradrenergic system using cat models. We then look at the importance of using cross-species models in sleep research with flies, mice, rats and humans. We also discuss the different ways of using these animal models and the different advantages they offer for sleep research.

We then move on to Chiara's Synaptic Homeostasis Hypothesis. This hypothesis has been supported by data from a wide range of species, and suggests that an important function of sleep is to downscale synapses. During the day, brain connections (or synapses) relating to information we have learned get strengthened.  This can result in a kind of neural saturation, whereby there is no space for more synapses. The Synaptic Homeostasis Hypothesis proposes that these synapses are downscaled during sleep, bringing about a form of homeostasis that allows us to repeatedly strengthen synapses during wake and downscale during sleep.

We also take a look at different ways of measuring synaptic growth across species such as molecular studies, structural or electrophysiological studies and the current difficulties in following synapses over long periods of time.

Finally, we look at Chiara's most recent finding which shows synapses associated with new learning are protected from downscaling during sleep.  Instead, her latest data show that it is the background noise that is reduced during sleep, allowing for an increase in signal to noise ratio.

We hope you enjoy the episode and please find more information below. 

Here are links to some of the studies mentioned in the podcast:

• Synaptic Homeostasis Hypothesis 
• Synaptic Homeostasis Hypothesis in Memory Consolidation 
• Downscaling 

If you would like to find more information of Chiara's work, you can find a link to her research page here.

Glossary of terms
Synaptic Homeostasis  - Renormalistion of overall synaptic strength to restore cellular homeostasis, preventing saturation and allowing further memory formation following a day of learning  

ATP 'cost' - ATP is our source of energy for everything that we do. An ATP 'cost' would refer to how much cellular energy something would use.

Declarative learning - Learning about knowledge which we can talk about e.g dates, facts, events.  

Drosophila - a genus of flies, commonly referred to as fruit flies, which are used regularly in scientific research.

Smart down selection - A process of selectively protecting synapses which need to be kept during downscaling.

Phosphorylation - Process of adding a phosphoryl group to a molecule. Phosphorylation can help regulate cell signals or protein development often acting as a way of 'labeling' cells.

Noradrenergic System - A neurotransmitter system within our nervous system that is often associated with alertness or arousal.

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Episode produced by Sophie Sm

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 episode, we interviewed Professor Reto Huber, who leads a research group at the University Children’s Hospital, Zurich. Reto’s interests encompass sleep disorders, development, synaptic plasticity and regeneration. 

In this episode we discuss local sleep, a process whereby different parts of the brain express different depths of sleep or wake at different times. We consider the relationship of local sleep to phenomena such as sleep walking and sleep talking, and Reto explains a series of experiments exploring how local sleep relates to learning. 

We then consider the use of drosophila as a model to study sleep and the sleep homeostasis hypothesis before switching topic to discuss the developing brain and sleep. Reto explains some important experiments linking sleep to plasticity. We discuss the differences in slow wave activity throughout development, and how the activity corresponds to experience dependent plasticity. We then consider a potential link to childhood conditions such as ADHD. 

Finally, Reto explains closed loop auditory stimulation and some recent findings relating to local sleep and learning. We end the episode by exploring the potential use of the technique in clinical settings.

If you would like to read more on Reto's work, you can find a link to his publications here.

Glossary:

Local Sleep - A phenomenon in which different parts of the brain experience different depths of sleep or wake at different times.

Sleep Homeostasis- The optimal balancing of sleep and wake driven by sleep pressure and our circadian rhythms

Synaptic Homeostasis- Renormalising of overall synaptic strength to restore cellular homeostasis, prevent saturation and allow further memory formation following a day of learning 

ADHD- Attention Deficit Hyperactivity Disorder

Closed Loop Auditory Stimulation- A method designed to enhance slow wave activity during sleep through auditory stimuli

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Episode produced by Vanessa Hyde & Sophie 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.

In this episode we talk to  Professor Manuel Schabus  and Professor Kerstin Hoedlmoser from the Centre for Cognitive Neuroscience at the University of Salzburg. 

In this episode, we discuss their work on the development of sleep-in babies, first discussing what baby sleep is like and how it differs from older children and adults in regard to activity and sleep stages and specifically sleep spindles and why we think this is. We also look at the difficulties of recording sleep in babies and what other methods are used to analyse and assess baby sleep. 

We then look in depth at the development on sleep spindles in babies and go on to discuss the difference between fast and slow spindles and their hypothesised importance in connection with memory consolidation and learning. 

We also discuss the importance of coupling activity and synchrony in the brain, specifically sleep spindles and slow oscillations and how these synchronise as we grow and develop and why this synchrony is important for memory and cognitive function.

 
If you'd like to find out more about Manuel's work you can find a link to his research page here and a link to Kerstin's research page here.

Here are links to some of the studies mentioned in the podcast:

        o Fast and slow spindles and their connection to cognitive and memory function
        o  Coupling of slow oscillations and sleep spindles and motor learning
        o  Coupling of slow oscillations and sleep spindles and memory

Glossary of terms

Sleep Spindle  - These are a burst of neural activity which usually occur during stage 2 non-REM sleep.

(Synaptic) Pruning  - The natural removal of extra synaptic connections between neurons which occurs between childhood and adulthood.

Declarative learning - A type of learning about knowledge which we can talk about e.g dates, facts, events. Episodic memory and semantic memory are types of declarative learning.

Alpha Activity - A pattern of electric actvity in the brain, alpha activity predominately occurs during rest with a frequency between 9-11Hz.   


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Episode produced by Sophie Smith & Bianca Strete

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.