In this episode, we talk to Professor Wenbiao Gan from the Neuroscience and Physiology and Skirball Institute at New York University School of Medicine.

Professor Gan tells us about how he started to become interested in studying sleep and its impact on learning and memory.

He talks about intriguing and hands-on ways to assess the formation and elimination of dendritic spines in  the mouse cortex, and how different experimental tasks like running backwards on a treadmill influence spine formation with or without sleep. Some counterintuitive results are presented and Professor Gan also shares his perspective on the synaptic homeostasis hypothesis.

In the end, Professor Gan gives some thoughts about the future of sleep research and suggests new methods of improvement in the area.

If you would like to find out more, here is a link to Professor Gan's full list of publications:

Links to  the studies mentioned in the podcast:

• REM sleep promotes experience-dependent dendritic spine elimination in the mouse cortex
• Fear extinction reverses dendritic spine formation induced by fear conditioning in the mouse auditory cortex
• REM sleep selectively prunes and maintains new synapses in development and learning
• Experience‐dependent plasticity of dendritic spines of layer 2/3 pyramidal neurons in the mouse cortex
• Two-photon microscopy as a tool to investigate the therapeutic time window of methylprednisolone in a mouse spinal cord injury model
• Sleep contributes to dendritic spine formation and elimination in the developing mouse somatosensory cortex

Glossary of terms 

• (synaptic) pruning = a natural phase in the development of the nervous system during which connections between neurons that are no longer needed die off
•  dendrites = tree-like extensions of the neuron
•  dendritic spines = extensions of a dendrite that help receive information from other neurons
• synaptic homeostasis = the idea that neural synapses cannot keep strengthening forever.  Instead, they must also downscale at some point in order to make space for further strengthening.  Such downscaling can be done in a relative manner that preserves information coded by the synapses in question.  

Episode produced by Bianca Strete and Sophie Smith