Circadian Rhythms and New Insights on Sleep

During the final week of my Neuroscience Seminar class, we had the privilege of learning and discussing the neurobiology of sleep and circadian rhythms in fruit flies. Daniel J. Cavanaugh presented the interesting findings in detail to reveal how LPNs regulate rest-activity rhythms in fruit flies. Essentially, the goal of Cavanaugh and colleagues was to determine whether LPNs require internal molecular clocks, whether communication between other neurons is necessary for these processes to function properly, and if and how temperature affects the circadian system. Cavanaugh addressed the results in class, which were quite successful. The experiments were able to determine that removing the molecular clocks in LPNs had almost no effect on the flies' circadian patterns, which indicates that they do not require their own molecular clocks in order to take part in this system. Turning off the ability of LPNs to communicate with other neurons did result in a reduction of sleep, specifically in evening hours. The portion of the study that involved temperature is still fairly new, but as one may know, many organisms' internal levels adapt to their external ones. It was found that LPNs are temperature sensitive, specifically to heat, and that this fact does affect their circadian patterns.

​    In the research article, “Sleep is essential — researchers are trying to work out why”, Tammy Worth walks us through the factors that prove the significance of good sleep goes beyond basic benefits. Results from the experiment indicate that when mice and flies did not get a sufficient amount of sleep, they would die much sooner than anticipated. Although many initially believe that death due to sleep deprivation is a result of brain damage, that was interestingly not the case. It was revealed that sleep deprivation leads to an increase in toxins in the stomach, which can be fatal. Research also revealed that not only does good sleep quality remove toxins from the gut, but also from the brain. These processes are crucial to one's well-being because if not regulated, they can lead to issues like Alzheimer's. It is good to be mindful that this idea is challenged by other scientists and that the research remains ongoing.

    The study addressing why sleep is essential and Daniel Cavanaugh's study relate to one another in numerous ways. Both researchers acknowledge that sleep and the circadian rhythm are crucial in one's life. Even though they focus on slightly different things, I found it interesting that both studies use fruit flies to test their hypothesis. Cavanaugh's research revealed the mechanisms used in flies to unwind the circadian clock process, whereas Worth used fruit flies to prove that sleep deprivation resulting in poor gut health can be deadly. Both studies examine the process of homeostasis and how the brain and body reset during sleep to optimize performance for the next day. Although the big questions in these two papers were far different, as one was asking how and the other asking why, both addressed processes that go hand in hand with one another, which was very enjoyable coming from the reader. 

References:

Worth, Tammy. “Sleep Is Essential — Researchers Are Trying to Work out Why.” Nature, 9 Apr. 2025, www.nature.com/articles/d41586-025-00964-w, https://doi.org/10.1038/d41586-025-00964-w.

Guerrero, Charlene Y P, et al. “The Cell-Intrinsic Circadian Clock Is Dispensable for Lateral Posterior Clock Neuron Regulation of Drosophila Rest-Activity Rhythms.” Neurobiology of Sleep and Circadian Rhythms, vol. 18, 2025, p. 100124, pubmed.ncbi.nlm.nih.gov/40386580/, https://doi.org/10.1016/j.nbscr.2025.100124.