The role of sleep in memory and brain maturation

Background

We paradoxically know very little about sleep, especially when it is most abundant and arguably most needed: early in life. Large sleep amount is a hallmark of altricial young mammals, such as humans or rodents, born in underdeveloped states and whose brain goes through extensive postnatal maturation processes. Our core working hypothesis in the lab is that important processes occurring during sleep are necessary to ensure healthy cognitive development. In support to this idea, studies point to altered sleep in children diagnosed with neurodevelopmental, psychiatric, or learning disorders¹ . It has been suggested that poor sleep early in life can lead to aberrant synaptic pruning^2,3 and pathologic reorganization of the thalamic-cortical circuits^4,5 needed for mature brain functions^1,6,7.

In our modern society, poor sleep hygiene among children is a growing concern for public health, but the mechanisms by which sleep is needed for healthy brain development remains elusive. In this framework, our lab maps how sleep mature postnatally and may impact the development of brain network and cognitive functions (e.g., learning/memory, social interactions). To that end, we record elecrophysiological activity from multiple regions of the brain (i.e.: hippocampus, and cortex) of freely moving rodents, while they perform behavioural tasks. We apply sleep alteration protocols during early development, and perform immunohistochemistry to assess neuronal maturation, in combination with cutting-edge analysis of electrophysiological signals to study brain functionality, including network connectivity and sleep classification.

Project

This master project will be a part of the ERC funded project SleepCog, focusing on the role of sleep in healthy cognitive development. The thesis can entail different aspects of the workflow, from surgeries, behavioural testing, electrophysiological recordings, performing sleep deprivation protocols and data/tissue analysis. The exact workflow will be adapted to the interests and experiences of the student.

Methods

The student will either be working with animals, in vitro techniques, or analysis of data. Depending on the project, the student can learn a wide range of methods such as surgical implantation of electrodes, behavioural testing (Y-maze and Delayed Non-Match to Position task), sleep deprivation protocols, electrophysiological recordings/data analysis, tissue harvest, tissue fixation, tissue slicing, immunohistochemistry, imaging, etc.

About the student

We are looking for a motivated and independent student with a background in biology/physiology/neuroscience. As this project is based on animal work, a CAREiN animal certificate and previous animal experience are a big advantage. Previous experience with lab techniques or electrophysiology is also a plus.

About us

For this master project, the student will be welcomed into an interdisciplinary environment bridging neurodevelopment biology, systems neuroscience and sleep research at the Norwegian Centre for Molecular Biosciences and Medicine (boccaralab).

If you find this project interesting and want to learn more about sleep and cognitive development, please contact us by e-mail:
alessandro.arena@ncmbm.uio.no and/or charlonb@uio.no

References

1. Medina, E., Peterson, S., Ford, K., Singletary, K. & Peixoto, L. Critical periods and Autism Spectrum Disorders, a role for sleep. Neurobiol Sleep Circadian Rhythms 14, (2023).
2. Li, W., Ma, L., Yang, G. & Gan, W. B. REM sleep selectively prunes and maintains new synapses in development and learning. Nat Neurosci 20, 427¨C437 (2017).
3. Zhou, Y. et al. REM sleep promotes experience-dependent dendritic spine elimination in the mouse cortex. Nat Commun 11, (2020).
4. Bridi, M. C. D. et al. Rapid eye movement sleep promotes cortical plasticity in the developing brain. Sci Adv 1, (2015).
5. Frank, M. G., Issa, N. P. & Stryker, M. P. Sleep Enhances Plasticity in the Developing Visual Cortex. Neuron 30, 275¨C287 (2001).
6. Hensch, T. K. Critical period plasticity in local cortical circuits. Nature Reviews Neuroscience vol. 6 877¨C888 Preprint at https://doi.org/10.1038/nrn1787 (2005).
7. Reha, R. K. et al. Critical period regulation across multiple timescales. Proceedings of the National Academy of Sciences of the United States of America vol. 117 23242¨C23251 Preprint at https://doi.org/10.1073/pnas.1820836117 (2020).