The phenomena of motivation cannot be studied separately as an independent research topic because motivation is highly interrelated to cognition, emotion, learning, and decision-making process. The overarching aim of this volume, therefore, is to provide new insight into a unified grand theory of motivation by integrating noteworthy neuroscience research findings on motivation. This volume is dedicated to advancing our understanding of brain mechanisms of underlying various motivational phenomena, including reward, approach, autonomy, intrinsic motivation, learning, effort, curiosity, and...