The Human Affectome Project: A dedication to Jaak Panksepp.

Mapping the neural basis of the Affectome was certainly the goal of Jaak Panksepp as he extended the work of a long line of thinkers from William James to Paul Maclean. Jaak's contribution was not just an incremental step, but a move to embrace feelings as a key component of affective science. His goal was to develop objective behavioral measures as he identified the neural substrates associated with affective states. He dedicated his career to studying the biological roots of emotional operating systems and his 1998 book "Affective Neuroscience" stands as a seminal accomplishment that provided a foundation for a field of research that has flourished since. His influences can be seen in many of the reviews created for this project and his early references to comfort zones are central to the human affectome. Indeed, Jaak was a tireless investigator who challenged our thinking, and he gave us many insights and gifts. We are immensely grateful for his contributions and this special issue is dedicated to his memory.

The role of hedonics in the Human Affectome.

Experiencing pleasure and displeasure is a fundamental part of life. Hedonics guide behavior, affect decision-making, induce learning, and much more. As the positive and negative valence of feelings, hedonics are core processes that accompany emotion, motivation, and bodily states. Here, the affective neuroscience of pleasure and displeasure that has largely focused on the investigation of reward and pain processing, is reviewed. We describe the neurobiological systems of hedonics and factors that modulate hedonic experiences (e.g., cognition, learning, sensory input). Further, we review maladaptive and adaptive pleasure and displeasure functions in mental disorders and well-being, as well as the experience of aesthetics. As a centerpiece of the Human Affectome Project, language used to express pleasure and displeasure was also analyzed, and showed that most of these analyzed words overlap with expressions of emotions, actions, and bodily states. Our review shows that hedonics are typically investigated as processes that accompany other functions, but the mechanisms of hedonics (as core processes) have not been fully elucidated.