Trained as an electrophysiologist, Dr. Gao’s early interests laid in investigating the modulation of activity in developing and mature hypothalamic neurons by neurotransmitters, neuropeptides and neurotrophic factors. He is the first investigator to characterize the cellular functions of neuropeptides hypocretin/orexin and melanin-concentrating hormone (MCH) in nerve cells in the central nervous system (CNS). After establishing an independent research group at Yale, his current interests are to understand how biological processes at molecular, cellular and systems levels lead to the emergence of physiological functions (such as energy balance and sleep/wake regulation) and complex behaviors (such as reward seek/addiction, stress coping strategy and social behaviors) critical to animal survival. The group’s major discoveries provide first evidence that experience-dependent neural plasticity in neuronal systems (such as the hypocretinergic and MCHergic systems) in the lateral hypothalamus underlies promotion of positive energy balance and maintenance of wakefulness and arousal, which may contribute to the development of insomnia, drug addiction and obesity-associated behavioral changes in animals.