Circadian Rhythm and Lateral Posterior Neurons (LPNs)

     To finish off the semester, we had the pleasure of hearing from Dr. Cavanaugh and his presentation on the paper “The cell-intrinsic circadian clock is dispensable for lateral posterior clock neuron regulation of Drosophila rest-activity rhythms”. In this presentation, Dr. Cavanaugh explores the topic of circadian rhythm and our body's natural clock using Drosophila. More specifically, the presentation dived into the aspects of lateral posterior neurons (LPNs) and its effects on rhythm behavior and output. It was found that eliminating LPNs intrinsic clocks had little effect on rhythmic behavior, implying that rhythmic inputs from larger biological clocks can drive LPN activity even without their own biological clock. The presentation concluded with the fact that LPNs are not refined locomotor patterns that have the ability to make neuronal output and connection to other clock cells

    The paper “Circadian rhythm and disease: Relationship, new insights, and future perspectives” by Ana R. Neves published in 2022 explores the functional diversity of clock neurons and their contribution to circadian behavior. The article highlights how diverse networks like LPNs, lateral dorsal neurons (DN1ps), and ventrolateral neurons (sLNvs) coordinate daily to generate rhythm, adjusting to environmental cues and factors. The paper emphasizes the importance of intercellular communication between these neurons and how manipulation of these neurons can shift or degrade circadian patterns, backing the idea that no single neuron dictates an entire system, rather it takes a robust cluster of them to contribute to a clock network. 

Dr. Cavanaugh's presentation expands on Neves' paper by zooming in on a specific less understood group of neurons, the LPNs, and providing sufficient evidence in how they play a role in the circadian network. Neves' paper outlines the eternal structure of a Drosophila clock, emphasizing its emergence from an overlap of many neurons. Dr. Cavanaugh takes this further by demonstrating exactly what happens when one of those clusters is functionally disrupted. I think it is imperative that further research is conducted on these specific neurons and how they communicate between each other for proper function and orientation. 

References:

Guerrero, C. Y. P., Cusick, M. R., Samaras, A. J., Shamon, N. S., & Cavanaugh, D. J. (2025). The cell-intrinsic circadian clock is dispensable for lateral posterior clock neuron regulation of drosophila rest-activity rhythms. Neurobiology of Sleep and Circadian Rhythms, 18, 100124. https://doi.org/10.1016/j.nbscr.2025.100124 

Neves, A. R., Albuquerque, T., Quintela, T., & Costa, D. (2022). Circadian rhythm and disease: Relationship, New Insights, and future perspectives. Journal of Cellular Physiology, 237(8), 3239–3256. https://doi.org/10.1002/jcp.30815