Recent advances in roles of midbrain periaqueductal gray in regulating behaviors and emotions

Midbrain periaqueductal gray (PAG) is the midline structure of the brain and plays a crucial role in the regulation of a series of physiological functions, emotions and motivated behaviors. In recent years, with the developments of functional tracer technology, genetic technology and neuroimaging technology, the understandings of physiological and psychological functions of PAG have been expanded. The recent research progresses of PAG in the neural circuits in regulation of behaviors, emotions and the related mechanisms are reviewed. Key words: Gray matter; Mesencephalic aqueduct; Behavior; Emotion; Neural circuit