Why do we sleep?

Why we sleep remains one of the most enduring mysteries in science. Sleep is homeostatically regulated where the duration of wakefulness drives subsequent sleep. Here we aim to determine how waking experience is sensed to trigger sleep and how sleep restores the brain? How the circadian clock interacts with sleep homeostasis? How impaired sleep lead to human diseases such as Alzheimer’s disease?

why do we sleep?

Why we sleep remains one of the most enduring mysteries in science. Sleep is homeostatically regulated where the duration of wakefulness drives subsequent sleep. Here we aim to determine how waking experience is sensed to trigger sleep and how sleep restores the brain? How the circadian clock interacts with sleep homeostasis? How impaired sleep lead to human diseases such as Alzheimer’s disease?


Nearly every organism examined, even the jellyfish that lacks a centralized nervous system, exhibits a restorative sleep-like state. While asleep, we cannot eat, mate, defend ourselves from predators or care for our young. Inadequate sleep contributes to brain disease such as Alzheimer’s and depression, and even diseases outside of the brain, such as diabetes and obesity.  Sleep is homeostatically regulated, i.e., sleep is driven by the duration and intensity of prior waking experience.  Our principal goals are to identify the neuronal and molecular components of the sleep homeostat, to understand how those components cooperate to sense and control sleep-wake state, and to reveal how molecular and neural homeostatic pathways impact brain function, health, and disease.  Our strategy employs genetic tools primarily in the fruit fly Drosophila to dissect, manipulate and monitor the homeostatic machinery. This approach builds on our research to understand the molecular basis of circadian (~24 h) behavior which have revealed sleep mechanisms conserved between invertebrates and vertebrates and incorporates work in both mice and humans.

Circadian Rhythms

Circadian clocks dictate when we wake up and when we fall asleep.  Using molecular to behavioral approaches primarily in the fruit fly  we aim to  reveal the molecular and neuronal mechanisms by which circadian clocks keep time and convey that information to control sleep/wake?  We are also determining the mechanistic role of disrupted circadian clocks in neurodevelopmental (e.g. autism) and neurodegenerative (e.g. Huntington’s disease disorders.

Sleep Homeostasis

The elusive sleep homeostat drives sleep as a function of prior wakefulness. How does the homeostat sense waking experience, trigger sleep and restore the brain to a baseline healthy state? By combining genetics, genomics, real-time imaging, and high resolution behavior analysis, we aim to identify the locus of the sleep homeostat and understand the molecular mechanisms that govern homeostat function. We are also determining how disrupted sleep can contribute to neurodegenerative disorders such as Alzheimer’s disease.

Humans: Diagnostics/Jet Lag

Disrupted sleep and circadian rhythms have been increasingly associated with neural (depression and Alzheimer’s) and even non-neural disorders (diabetes and obesity). Here we are combining RNA-sequencing with machine learning algorithms to discover biomarker signatures of sleep and circadian disorders. We are also using publicly available data to assess the effects of sleep/circadian disruption on athletic performance.


Ravi Allada

Principal Investigator 

MD, University of Michigan, Ann Arbor
BA, University of Michigan, Ann Arbor

On his way to becoming a medical doctor, Ravi decided to take a year (and then two) off during medical school to do research at the NIH.  There he caught the research ”bug” and began his career-long interest in sleep, working on mechanisms of general anesthesia in the fruit fly Drosophila. After completing his M.D and a short residency in Clinical Pathology, he did his postdoctoral training with Nobel laureate Michael Rosbash, cloning the core circadian clock gene Clock in Drosophila.  He joined the faculty at Northwestern in 2000 where his lab has discovered core gears of the circadian clock, how those gears drive sleep and wake, and how those pathways are linked to neurodegenerative disease.  He applies similar approaches to reveal the molecular basis of the sleep homeostat, key to understanding the elusive function of sleep. In his spare time, he has served or is serving on various Boards including for the Society for Research on Biological Rhythms, the Sleep Research Society and the NIH Sleep Disorders Research Advisory Board.

Tomas Andreani

PhD Graduate Student

Bachelors, Pitzer College

Tomas received his bachelors at Pitzer College in Southern California but his first taste of science was at Brown University under Dr. Suzanne de la Monte studying the role of nitrosamines and alcohol on neurodevelopment. His love of learning and teaching inspired him to pursue a PhD in neuroscience through the Northwestern University interdepartmental neuroscience (NUIN) program. His work in the Allada lab focuses on the cellular and molecular correlates of sleep homeostasis and how waking experience translates to sleep drive.

Wenhao Cao

Research Technologist

MS in Biotechnology, Northwestern University
BS in Biochemical Engineering, Catholic University of Leuven (KU Leuven), Leuven, Belgium

Wenhao grew up in China and went to Belgium for his undergraduate study. After living in Europe for several years he decided that U.S. would be the next place to explore. While studying engineering at Northwestern, he found his interests in neurodegenerative disease by accident and joined the Allada lab to work on Huntington’s Disease for his graduate research. He is now a lab technician working on the ENCODE Project. He loves travelling and experiencing different culture.

Vanessa Hernandez

Masters Student

BS in Psychology, Arizona State University
BS in Biology, Arizona State University 

Vanessa pursued concurrent undergraduate degrees in Biology and Psychology from Arizona State University. Currently, she is part of the Neurobiology Master’s Program. She is interested in studying the interaction between sleep, circadian rhythm disruption, and Alzheimer’s Disease. If you have any questions about her experience in the Master’s Program, please feel free to reach out.

Bridget Lear

Research Associate Professor

BS University of California at Los Angeles
PhD University of Chicago

As a Ph.D. student, Bridget studied nervous system development and evolution with Dr. Nipam Patel. She then moved to the field of circadian rhythms, where she has focused on understanding the neural mechanisms regulating circadian behavior. As a postdoctoral fellow (Allada lab), Bridget helped identify the receptor for the PDF neuropeptide, a critical component of clock neuron communication in Drosophila. Her postdoctoral work also established an important role for the sodium leak channel Narrow Abdomen (aka NALCN) in circadian neuron output. As a faculty member (U. of Iowa 2010-2018; Northwestern U. 2009-10, 2018-present) she has continued to study the regulation and function of the Narrow Abdomen ion channel complex in the circadian system. She has also focused on understanding the complex relationship between neuronal network communication, environmental input, and circadian behavioral output.

Zhichun Lin

Masters Student

BS in Biological Science & Psychology, University of Connecticut

Zhichun, aka Michael, graduated from the University of Connecticut. His grandmother has been suffering from Alzheimer’s Disease for years. So he decided to focus his study on Alzheimer in order to help his grandmother and many other people who are also suffering from this disease. Currently, he is still learning all kinds of stuff in the Allada lab, studying the relationship between Alzheimer’s Disease, circadian rhythm disruption and sleep quality.

Eugene Nyamugenda

Postdoctoral Fellow

PhD, University of Arkansas for Medical Sciences

Eugene is from Rwanda. After high school, he received a presidential scholarship to study for a bachelor’s degree at Hendrix College in Conway Arkansas. After receiving a BA in Biochemistry and molecular biology, He enrolled in the Ph.D. program at the University of Arkansas for Medical Sciences. Eugene’s Ph.D. thesis was on identifying neurons of the hypothalamus that are the target of the damage of lipid stress observed in diet-induced obesity. In Allada Lab, Eugene is interested in many things. Chief among them are studying the molecular function of sleep in alleviating neurological diseases, identifying genes and pathways important for the function of sleep in slowing down Alzheimer’s disease, and anything that involves genetic manipulation because it is fun. Outside the lab, He enjoys running, lifting weights (mostly his children), eating anything that is not vegetables, and hanging out with his wife and

Jack Qin

Masters Student

MBS, University of Melbourne, Australia
BS, Swinburne University of Technology, Australia
BS, Central China Normal University

Jack did his undergraduate in both China and Australia majoring in Biotechnology, he was intrigued by Neuroscience since his sophomore year, especially neural diseases studies. Now he’s doing a project about the interactions between circadian rhythms and Huntington’s disease. He loves music, especially classical ones. and was a violinist in his undergraduate university’s symphony orchestra.

Clark Rosensweig

Postdoctoral Fellow

PhD, University of Texas Southwestern Medical Center
BA, Harvard University

Clark grew up in a sleepy beach community in South Florida. After college, he dropped out of science to pursue a career in stand up comedy, then dropped out of stand up comedy to pursue a career in science. As a graduate student in Carla Green’s lab, he performed structure/function studies of the circadian repressors Cryptochrome 1 and 2 and identified a subtle structural divergence between the two with a major role in determining periodicity in the mammalian circadian clock. Clark brought his penchant for biochemistry to the Allada lab to determine why we sleep. He has subsequently become a more interesting dinner party guest.

Shiju Sisobhan

Postdoctoral Fellow

I grew up in the beautiful state of Kerala (India) where I received my bachelor’s and master’s degree in electronics engineering. Then I relocate to Delhi, where I did my Ph.D. in computational biology under Dr. K. Sriram. My work in Ph.D. studies focused on the mathematical modeling of the mammalian circadian rhythm. In the Allada lab, I am focusing on developing computational tools for analyzing sleep and circadian behavior of Drosophila and human being. I am also working on bioinformatics analysis on RNA seq data from sleep-deprived Drosophila.

Alec Victorsen

Research Technologist

BS, Iowa State University
MS, Iowa State University

Alec became familiar with recombineering, a technique for sequence specifically modifying large DNA molecules, while studying antibiotic persistence in Salmonella at Iowa State. This technique was instrumental to his early work on the modERN project. He currently manages the lab’s contribution to the modERN project, with the goal of assaying all transcription factors by ChIP-seq in Drosophila melanogaster.

Gregory Wesseling

Research Technologist

Masters, Grand Valley State University

Bachelors, Central Michigan University

In graduate school at GVSU, Greg dissected larval drosophila brains to investigate histamine expression in deletion mutants generated through transposon-excision mutagenesis. When Greg joined the Allada lab, he dissected adult drosophila brains to investigate PER expression. Greg now works on project ENCODE to help document where transcription factors act in the fly genome. Before graduate school, Greg spent a summer at the University of Cambridge to study evolution. In his spare time, Greg enjoys watching college football and basketball.

Elizabeth Williamson

Research Technologist

BA in Biochemistry & Biophysics, Northwestern University

Elli studied biochemistry & biophysics at Northwestern, and is particularly interested in bioinorganic chemistry. Before working in a lab, she was a professional illustrator. In her free time, she likes to play board games and photograph insects.

Melanie Zhang

PhD Graduate Student

BS in Neuroscience & Behavioral Biology, Emory University
BA in Music, Emory University

Melanie is interested in studying the interaction between sleep, circadian rhythm disruption and Alzheimer’s Disease. She is also a brain tumor and brain surgery survivor, so ask her anything.


coming soon…

Selected Publications

Join the Lab

The goals of the Allada laboratory are to make important discoveries in the areas of sleep and circadian rhythms and to provide engaged scientific training and an inclusive environment for a diverse group of postdoctoral fellows, graduate students, and undergraduates. To accomplish this goal, we (mentor and mentees) collaborate by proposing novel and insightful hypotheses, carefully planning and executing well-designed experiments, rigorously and quantitatively analyzing experimental results, and lastly, interpreting results in light of controls and the published literature.  Ultimately, the tangible products of our collective efforts are high impact publications that communicate our findings, competitive grant proposals that provide the funding necessary to sustain our efforts, and future careers for trainees whether in academia or elsewhere.

The Allada laboratory seeks energetic and highly motivated individuals who can excel as part of a team diverse in background, training.  Our research incorporates a wide range of multidisciplinary approaches including molecular (e.g., RNA sequencing, luminescence reporter imaging), cellular (e.g, connectomics, optical imaging), and behavioral (e.g., in vivo neuronal activation). Experience with molecular biology, RNA-sequencing, bioinformatics, patch clamp electrophysiology, optical imaging, and/or Drosophila highly preferred. We are located on the Evanston campus of Northwestern University, located on Lake Michigan just outside of Chicago.

Postdoctoral Fellows

Interested individuals should send a brief statement of research interests, CV, and the names of three references by email to r-allada@northwestern.edu.

PhD Students

Prospective PhD graduate students should apply to a relevant graduate training program at Northwestern such as NUIN or IBiS. Deadlines are typically at the beginning of December. Enrolled students interested in organizing a rotation in the Allada Lab should contact Dr. Ravi Allada directly at r-allada@northwestern.edu.

MS Students

Prospective M.S graduate students should apply to the Neurobiology M.S. program (https://neurobiology.northwestern.edu/graduate/program-overview/) for a one-year research intensive experience.


If you are an undergraduate interested in conducting research enrolled in independent study, full-time summer research, or in lab assistance through the work study program (work study website), please email allada-lab@northwestern.edu.

Contact us

Ravi Allada, MD

2200 Campus Drive
Room 2-121
Evanston, IL 60201

Phone: 847-491-2809
Email: r-allada@northwestern.edu

The Allada Lab

2200 Campus Drive
Room 2-201
Evanston, IL 60201

Mailing Address:
2205 Tech Drive
Hogan 2-160
Evanston, IL 60208

Phone: 847-467-7785