Perelman School of Medicine at the University of Pennsylvania

Sehgal Lab

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Credit: Anna King

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Research Overview

The laboratory seeks to understand the molecular and cellular networks that drive behavior, in particular rhythmic behaviors such as sleep.  Our studies are done largely with the fruit fly, Drosophila melanogaster, but we also translate our findings to mammalian models, especially mice.  The major goals are to elucidate the mechanisms that confer a circadian (~24-hour) periodicity on much of behavior and physiology as well as understand how and why the drive to sleep is generated.

Circadian (~24-hour) clocks endogenous to most organisms drive daily rhythms of sleep:wake and of most physiological processes.  Any kind of desynchrony between endogenous clocks and the environment, as is caused by travel to a different time zone or by shift work, results in a multitude of physiological disturbances.  Likewise, sleep disruption, which is common in modern society, results in severe metabolic and cognitive deficits.

Our research has provided insight into mechanisms of the circadian clock, how clocks synchronize to light and how clocks interact with body systems to drive rhythms of behavior and physiology.  Building upon a Drosophila model for sleep that we developed several years ago, we have also identified genes and circuits that underlie the homeostatic drive for sleep. Ongoing studies are revealing new mechanisms and cellular functions for sleep.  Together our studies are providing a comprehensive understanding of how internal clocks drive body rhythms, how and why a sleep state occurs, and the extent to which clocks and sleep impact general physiology and aging.


Videos/Articles that Feature the Lab:

Penn Medicine News: "Clock in Blood Brain Barrier of Fruit Flies Regulates Daily Permeability"

The Scientist Daily: "Fly's Blood-Brain Barrier Has Circadian Rhythms"

Bloomberg: "What Humans Can Learn from Sleep-Deprived Fruit Flies"

Washington Post: "Nobel in Physiology, Medicine Awarded to Three Americans for Discovery of 'Clock Genes'."

Huffington Post: "What Fruit Flies Can Tell Us About Human Sleep and Circadian Disorders"

The Scientist: "Time, Flies"

Medical Xpress: "Living by the Clock: The Science of Chronobiology"

PBS NOVA Interview with Neil deGrasse Tyson


We are also associated with the Penn Chronobiology Group.