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. 02:45 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. 06:16 Do dreams do anything for us? - Answered by Kyrillos Meshreky

• The brain as a dream state generator:
• Converging theories on dreaming
• Predictive coding under the free-energy principle

3. 09:49 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. 12:31 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. 17:33 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

6. 20:20 Does the menstrual cycle affect our sleep? - Answered by Marta Wawrzuta

7. 24:17 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:
• Seasonal variation in the human circadian rhythm

Host Professor Penny Lewis
Produced and edited by Sophie Smith

Check out our NaPS website to find out more about our team, 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

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 Smith

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