Northeastern Course Unlocks Secrets of the Body’s Internal Clock | Circadian Rhythm Research

The human body operates on a multitude of internal rhythms, most famously the circadian rhythm – the roughly 24-hour cycle governing sleep and wakefulness. But these rhythms aren’t simply a matter of feeling tired or alert. they permeate nearly every organ system, influencing everything from hormone release to immune function. A new course at Northeastern University is diving deep into the science of these “biological clocks,” challenging students to not just understand *what* these clocks do, but *how* they work, and why they’re so universally present across the tree of life.

The course, BIOL 5306: Biological Clocks, led by Associate Teaching Professor Matthias Schlichting, isn’t a typical survey of established knowledge. Instead, it adopts a historical, almost forensic approach, tasking students with critically examining the landmark experiments that built our current understanding of circadian biology. “We take something like a ‘time travel approach,’” Schlichting explains, “working chronologically through the major papers on the subject.”

This isn’t simply reading summaries. Students are expected to dissect the methodologies of these original studies, evaluating the rigor of the experimental design and questioning the conclusions drawn. Zaineb Irfan, a fourth-year biochemistry student, found this approach particularly valuable. “We were able to see the development of how the methodologies that are used in the field evolved,” she said. The goal, according to Schlichting, is to instill a sense of critical thinking and a deep appreciation for the scientific process.

The fundamental discovery that organisms possess internal clocks came from surprisingly simple observations. Researchers noted that even in the absence of external cues like sunlight, plants continued to exhibit rhythmic behaviors, such as the opening and closing of leaves. Identifying the underlying mechanisms, however, proved far more complex. Subsequent research revealed that clock genes are expressed in nearly all tissues, though specific “master” clock cells in the brain appear to exert primary control over the overall rhythm.

The implications of disrupted circadian rhythms extend far beyond simple sleep deprivation. Schlichting points to the increased cancer rates observed in shift workers, and the correlation between clock misalignment and breast cancer, as examples of the profound health consequences. Understanding these connections is driving increasing interest in chronobiology – the study of biological rhythms – and its potential for therapeutic interventions.

Brian Hulbert, a fifth-year student majoring in both biology and philosophy, praised the course’s seminar-style format and Schlichting’s ability to guide students through complex research papers. “What really was helpful…was how Dr. Schlichting helped us dissect figures and read research papers,” Hulbert noted, emphasizing the focus on understanding the data itself, rather than simply accepting authors’ interpretations.

Schlichting is also incorporating cutting-edge tools into the curriculum. Students are tasked with using artificial intelligence to summarize research papers, then critically comparing the AI-generated summaries to their own work. This exercise not only tests their comprehension of the material but also encourages them to evaluate the strengths and weaknesses of large language models. Irfan found that while the AI-generated summary was well-organized, it lacked the depth of detail present in her own analysis. Hulbert, initially skeptical of AI, now uses it as a tool to quickly scan large volumes of research.

The course also delves into the study of “clock mutants” – organisms with altered or disrupted clock genes, often fruit flies – to understand the specific roles of different genes and pathways in regulating circadian rhythms. A key question that continues to puzzle researchers is *why* these clocks operate on a roughly 24-hour cycle. “It is kind of weird,” Schlichting observes, “that this process actually takes 24 hours,” given that most gene expression processes occur much more rapidly.

Schlichting hopes the course will equip students with more than just knowledge of circadian biology. He aims to instill a rigorous approach to research, emphasizing the importance of critical thinking, experimental design, and careful data analysis. “Hopefully,” he adds, “it teaches students about rigor: The necessity of it, how to have it in their own research and how to spot it when it’s missing.” The course, isn’t just about understanding the body’s internal clocks; it’s about learning how to unlock the secrets of biological systems, one carefully scrutinized experiment at a time.