Dan’s sleep paper is accepted in Journal of Neuroscience

Congratulations, Dan and coauthors!  His paper “Sleep analysis in adult C. elegans reveals state-dependent alteration of neural and behavioral responses” is accepted at Journal of Neuroscience and is out in Early Release!

https://doi.org/10.1523/JNEUROSCI.1701-20.2020

In this paper, Dan asked a basic question regarding how the nervous system changes its sensory responses during sleep.  Sleep increases the sensory “arousal threshold”– it takes a louder sound (or smell, touch, etc.) to respond when sleeping versus awake– but why?  If senses are dulled during sleep, is it because the brain has less sensory information to work with, or is it actively not listening?  Dan uses the C. elegans model system to first characterize a relatively new form of adult spontaneous sleep (minutes-long rest periods happening a few times per hour) that is distinct from developmental or stress-induced sleep.  He then engineered a closed-loop neural imaging system that tracks animal behavior in real time, then triggers a sensory stimulation after falling asleep or waking up, all while recording both neural activity in different neurons and the resulting behavior. It’s all automatic, and measures many responses in the same animal over about 12 hours during each sleep state transition.  So what is the answer?  Well, it’s complicated… it seems to differ based on the stimulus (aversive or attractive), but in general the sensory neurons represent the sensory information faithfully. This suggests that the brain has all the sensory information, and it actively suppresses that information during sleep.  What might happen if this process goes awry? This is the subject of future studies.