Elena Gracheva is a Professor of Cellular and Molecular Physiology and of Neuroscience at Yale University School of Medicine. Her research focuses on uncovering the cellular, molecular and physiological basis of mammalian hibernation. She employs a multidisciplinary approach that includes electrophysiology, molecular biology, imaging, behavioural paradigms, genomics, transcriptomics and bioinformatics. Working with non-standard animal models such as hibernating thirteen-lined ground squirrels and Syrian hamsters, she delves into various aspects related to temperature sensitivity, thermoregulation, fluid ionic balance, hunger and satiety control, and seasonal reproduction.

Talk: Neurophysiological adaptations of hibernation: solutions to environmental challenges

Hibernation was first documented by Aristotle in 350 BCE, who noted that some creatures conceal themselves in a sleep-like state during winter. During hibernation animals undergo dramatic adaptive changes, including a reduction in heart and respiration rate and a decrease in core body temperature from 37°C to 4°C. Yet, despite being cold and deprived of oxygen for up to 8 months, they do not experience cold-induced pain, and their organs continue to function! Moreover, because these animals often do not eat or drink during hibernation, they must rely solely on the management and utilization of their internal resources. Hibernators exist in almost all mammalian groups, suggesting that hibernation results from modification of existing physiological pathways rather than evolution of novel traits. However, the mechanisms that support hibernation remain enigmatic.
Our goal is to reveal cellular, molecular, and circuitry mechanisms that induce and support hibernation in mammals. We seek to understand what enables hibernators’ survival during prolonged periods of hypothermia, water deprivation and starvation. Our research model is the thirteen-lined ground squirrel, an obligatory mammalian hibernator. We employ a wide array of experimental approaches, including single-molecule biophysics, cell biology, chemo- and optogenetics, neurophysiology and behavior. By combining cutting-edge molecular tools with the naturalistic animal model, we seek to revolutionize our understanding of the mechanisms underlying hibernation. 
Our research program tackles fundamental physiological questions from the unique perspective of mammalian hibernators. This work will lay foundation for rational design of pharmacological tools to understand how life in mammals can persist under extreme conditions of prolonged periods of hypothermia, cold exposure, starvation, and dehydration. Our discoveries will allow us to predict whether hibernation can be induced in other mammals, including humans.