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

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