Why do we need sleep?

Despite spending nearly one-third of our lives asleep, the fundamental purpose of sleep remains elusive. Our research seeks to uncover the mechanisms governing sleep and wakefulness and to understand how sleep contributes to brain function and health. We break this question down into two core questions:

1. How are sleep and wakefulness regulated?

Brain states are orchestrated by diverse neuromodulatory systems, including monoamines, neuropeptides, and lipid mediators. By combining newly developed genetically encoded fluorescent sensors for neuromodulators, we characterize the dynamic patterns of neuromodulator release across the sleep–wake cycle, with particular attention to neuromodulators exhibiting unique activity profiles during sleep. Using complementary approaches such as optogenetics, molecular biology, pharmacology, and neural circuit tracing, we further investigate the functions of these neuromodulatory systems and elucidate the neural circuit mechanisms through which they regulate sleep–wake transitions.

2. What are the functions of sleep?

Sleep is indispensable for restoring physiological function, maintaining homeostasis, regulating emotions, and consolidating memories, serving as a cornerstone of human health. We are particularly interested in neuromodulators that exhibit rhythmic oscillatory activity during both non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. By integrating electrophysiological recordings with in vivo imaging techniques, we aim to uncover the mechanisms underlying these rhythmic oscillations and determine their roles in emotional regulation and memory consolidation.

Approaches

Genetically encoded neuromodulator probes, optogenetics, in vivo electrophysiology, in vivo fluorescence imaging, neural circuit tracing, molecular biology and pharmacology.