In this episode, we’re joined by Dr. Niels Niethard from the University of Tübingen to explore what sleep looks like at the level of cortical microcircuits — and how excitation and inhibition are dynamically reconfigured across brain states.

Niels walks us through how excitatory pyramidal neurons interact with distinct inhibitory interneuron populations, including somatostatin (SST) and parvalbumin (PV) cells. We discuss how these cell-type-specific interactions shift from wakefulness to non-REM sleep and into REM, creating fundamentally different circuit configurations across sleep stages.

We discuss how sleep spindles, slow oscillations, and REM sleep each create distinct configurations of dendritic and somatic inhibition. Niels explains how spindle timing relative to slow oscillation peaks influences synaptic plasticity and how these processes support selective memory consolidation.

The conversation also touches on his work on synaptic downscaling in cortical and hypothalamic networks, the potential link between AMPA receptor regulation and sleep pressure, and how sleep interacts with feeding-related circuits and metabolic state in mice.

This episode offers a detailed, cell-type-specific perspective on how excitation and inhibition are balanced across sleep stages, revealing the microcircuit mechanisms underlying memory, synaptic downscaling, and brain homeostasis.

Find out more about Dr. Niethard’s lab and see relevant publications below:

• Cortical circuit activity underlying sleep slow oscillations and spindles. PNAS, 2018
• Slow-wave sleep drives sleep-dependent renormalization of synaptic AMPA receptor levels in the hypothalamus. PLOS Biolology, 2024
• Cell-type specific dynamics of calcium activity in cortical circuits over the course of slow wave sleep and rapid eye movement sleep. Journal of Neuroscience, 2021

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've gathered the NaPS lab to answer all your fascinating questions on all things sleep! A perfect bitesize episode to get stuck into the marvellous world of sleep.

1. How does sleep deprivation affect mental health? - Answered by Martha Wawrzuta

• Bunney, B. G. , Bunney, W. E. (2013). Mechanisms of Rapid Antidepressant Effects of Sleep Deprivation Therapy: Clock Genes and Circadian Rhythms. Biological Psychiatry
• Fang, H., Tu, S., Sheng, J., Shao, A. (2018). Depression in sleep disturbance: A review on a bidirectional relationship, mechanisms and treatment. Journal of Cellular and Molecular Medicine

2. What is narcolepsy? - Answered by Kyrillos Meshreky

• Leschziner G., Narcolepsy: a clinical review, Practical Neurology 2014;14:323-331

3. Does the full moon affect sleep? - Answered by Al Saqib Majumder

• Casiraghi, L. et al. (2021). Moonstruck sleep: Synchronization of human sleep with the moon cycle under field conditions.
• Chaput, J. P. et al. (2016). Are Children Like Werewolves? Full Moon and Its Association with Sleep and Activity Behaviors in an International Sample of Children. Sleep Medicine

4. How does a smart watch track sleep? - Answered by Yan Wang

5. What is orthosomnia? - Answered by Sophie Smith

• Baron, K.G., et al. (2017) Orthosomnia: Are some patients taking the quantified self too far? J Clin Sleep Med

6. What is sleep regression and how long does it last? - Answered by Mo Abdellahi

• Weinraub, M. et al. (2012). Patterns of developmental change in infants' nighttime sleep awakenings from 6 through 36 months of age. Developmental Psychology
• Bruni O. et al. (2014) Longitudinal study of sleep behavior in normal infants during the first year of life. J Clin Sleep Med

7. Does Magnesium Citrate help you sleep? - Answered by Dulni Peramunugamage

• Magnesium for sleep, Sleep Foundation, 2025

8. Does dark chocolate help you sleep? - Answered by Martha Nguyen

• Abdoli, E. et al. (2024). A clinical trial of the effects of cocoa rich chocolate on depression and sleep quality in menopausal women. Scientific reports,
• Garbarino, S., Garbarino, E., & Lanteri, P. (2022). Circadian Rhythm, Mood, and Temporal Patterns of Eating Chocolate: A Scoping Review of Physiology, Findings, and Future Directions. Nutrients

Music by Sergio Prosvirini from Pixabay

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 welcome neuroscientist Michele Bellesi from the University of Camerino to explore the fascinating world of glial cells and their dynamic role in sleep.

Michele guides us through the four types of glial cells:

• Astrocytes: Regulators of synaptic function and help form the blood brain barrier (BBB)
• Oligodendrocytes: Crucial for myelination and fast signal transmission
• Microglia: The brain's immune sentinels, important for responding to infection and injury as well as shaping the synaptic landscape
• Ependymal Cells: Involved in cerebrospinal fluid (CSF) production and CFS movement around the brain

We dive into how each of these cells types behaves differently across wake, sleep and sleep deprivation and the impacts on each cell types function.

Find out more about Michele's work here and see relevant papers below.

• The role of sleep and wakefulness in myelin plasticity, 2019, Glia
• Sleep loss promotes astrocytic phagocytosis and microglial activation in mouse cerebral cortex, 2017, Journal of Neuroscience
• Effects of sleep and wake on astrocytes: clues from molecular and ultrastructural studies, 2015, BMC Biology

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.